Initial implementation of C-source-level &&-idiom recovery

[valgrind.git] / VEX / priv / host_amd64_isel.c

/*---------------------------------------------------------------*/
/*--- begin                                 host_amd64_isel.c ---*/
/*---------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2004-2017 OpenWorks LLP
      info@open-works.net

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>.

   The GNU General Public License is contained in the file COPYING.

   Neither the names of the U.S. Department of Energy nor the
   University of California nor the names of its contributors may be
   used to endorse or promote products derived from this software
   without prior written permission.
*/

#include "libvex_basictypes.h"
#include "libvex_ir.h"
#include "libvex.h"

#include "ir_match.h"
#include "main_util.h"
#include "main_globals.h"
#include "host_generic_regs.h"
#include "host_generic_simd64.h"
#include "host_generic_simd128.h"
#include "host_generic_simd256.h"
#include "host_generic_maddf.h"
#include "host_amd64_defs.h"


/*---------------------------------------------------------*/
/*--- x87/SSE control word stuff                        ---*/
/*---------------------------------------------------------*/

/* Vex-generated code expects to run with the FPU set as follows: all
   exceptions masked, round-to-nearest, precision = 53 bits.  This
   corresponds to a FPU control word value of 0x027F.

   Similarly the SSE control word (%mxcsr) should be 0x1F80.

   %fpucw and %mxcsr should have these values on entry to
   Vex-generated code, and should those values should be
   unchanged at exit.
*/

#define DEFAULT_FPUCW 0x027F

#define DEFAULT_MXCSR 0x1F80

/* debugging only, do not use */
/* define DEFAULT_FPUCW 0x037F */


/*---------------------------------------------------------*/
/*--- misc helpers                                      ---*/
/*---------------------------------------------------------*/

/* These are duplicated in guest-amd64/toIR.c */
static IRExpr* unop ( IROp op, IRExpr* a )
{
   return IRExpr_Unop(op, a);
}

static IRExpr* binop ( IROp op, IRExpr* a1, IRExpr* a2 )
{
   return IRExpr_Binop(op, a1, a2);
}

static IRExpr* bind ( Int binder )
{
   return IRExpr_Binder(binder);
}

static Bool isZeroU8 ( const IRExpr* e )
{
   return e->tag == Iex_Const
          && e->Iex.Const.con->tag == Ico_U8
          && e->Iex.Const.con->Ico.U8 == 0;
}


/*---------------------------------------------------------*/
/*--- ISelEnv                                           ---*/
/*---------------------------------------------------------*/

/* This carries around:

   - A mapping from IRTemp to IRType, giving the type of any IRTemp we
     might encounter.  This is computed before insn selection starts,
     and does not change.

   - A mapping from IRTemp to HReg.  This tells the insn selector
     which virtual register is associated with each IRTemp
     temporary.  This is computed before insn selection starts, and
     does not change.  We expect this mapping to map precisely the
     same set of IRTemps as the type mapping does.

        - vregmap   holds the primary register for the IRTemp.
        - vregmapHI is only used for 128-bit integer-typed
             IRTemps.  It holds the identity of a second
             64-bit virtual HReg, which holds the high half
             of the value.

   - The host subarchitecture we are selecting insns for.  
     This is set at the start and does not change.

   - The code array, that is, the insns selected so far.

   - A counter, for generating new virtual registers.

   - A Bool for indicating whether we may generate chain-me
     instructions for control flow transfers, or whether we must use
     XAssisted.

   - The maximum guest address of any guest insn in this block.
     Actually, the address of the highest-addressed byte from any insn
     in this block.  Is set at the start and does not change.  This is
     used for detecting jumps which are definitely forward-edges from
     this block, and therefore can be made (chained) to the fast entry
     point of the destination, thereby avoiding the destination's
     event check.

   Note, this is all host-independent.  (JRS 20050201: well, kinda
   ... not completely.  Compare with ISelEnv for X86.)
*/

typedef
   struct {
      /* Constant -- are set at the start and do not change. */
      IRTypeEnv*   type_env;

      HReg*        vregmap;
      HReg*        vregmapHI;
      Int          n_vregmap;

      UInt         hwcaps;

      Bool         chainingAllowed;
      Addr64       max_ga;

      /* These are modified as we go along. */
      HInstrArray* code;
      Int          vreg_ctr;
   }
   ISelEnv;


static HReg lookupIRTemp ( ISelEnv* env, IRTemp tmp )
{
   vassert(tmp >= 0);
   vassert(tmp < env->n_vregmap);
   return env->vregmap[tmp];
}

static void lookupIRTempPair ( HReg* vrHI, HReg* vrLO, 
                               ISelEnv* env, IRTemp tmp )
{
   vassert(tmp >= 0);
   vassert(tmp < env->n_vregmap);
   vassert(! hregIsInvalid(env->vregmapHI[tmp]));
   *vrLO = env->vregmap[tmp];
   *vrHI = env->vregmapHI[tmp];
}

static void addInstr ( ISelEnv* env, AMD64Instr* instr )
{
   addHInstr(env->code, instr);
   if (vex_traceflags & VEX_TRACE_VCODE) {
      ppAMD64Instr(instr, True);
      vex_printf("\n");
   }
}

static HReg newVRegI ( ISelEnv* env )
{
   HReg reg = mkHReg(True/*virtual reg*/, HRcInt64, 0/*enc*/, env->vreg_ctr);
   env->vreg_ctr++;
   return reg;
}

static HReg newVRegV ( ISelEnv* env )
{
   HReg reg = mkHReg(True/*virtual reg*/, HRcVec128, 0/*enc*/, env->vreg_ctr);
   env->vreg_ctr++;
   return reg;
}


/*---------------------------------------------------------*/
/*--- ISEL: Forward declarations                        ---*/
/*---------------------------------------------------------*/

/* These are organised as iselXXX and iselXXX_wrk pairs.  The
   iselXXX_wrk do the real work, but are not to be called directly.
   For each XXX, iselXXX calls its iselXXX_wrk counterpart, then
   checks that all returned registers are virtual.  You should not
   call the _wrk version directly.
*/
static AMD64RMI*     iselIntExpr_RMI_wrk ( ISelEnv* env, const IRExpr* e );
static AMD64RMI*     iselIntExpr_RMI     ( ISelEnv* env, const IRExpr* e );

static AMD64RI*      iselIntExpr_RI_wrk  ( ISelEnv* env, const IRExpr* e );
static AMD64RI*      iselIntExpr_RI      ( ISelEnv* env, const IRExpr* e );

static AMD64RM*      iselIntExpr_RM_wrk  ( ISelEnv* env, const IRExpr* e );
static AMD64RM*      iselIntExpr_RM      ( ISelEnv* env, const IRExpr* e );

static HReg          iselIntExpr_R_wrk   ( ISelEnv* env, const IRExpr* e );
static HReg          iselIntExpr_R       ( ISelEnv* env, const IRExpr* e );

static AMD64AMode*   iselIntExpr_AMode_wrk ( ISelEnv* env, const IRExpr* e );
static AMD64AMode*   iselIntExpr_AMode     ( ISelEnv* env, const IRExpr* e );

static void          iselInt128Expr_wrk ( /*OUT*/HReg* rHi, HReg* rLo, 
                                          ISelEnv* env, const IRExpr* e );
static void          iselInt128Expr     ( /*OUT*/HReg* rHi, HReg* rLo, 
                                          ISelEnv* env, const IRExpr* e );

static AMD64CondCode iselCondCode_wrk    ( ISelEnv* env, const IRExpr* e );
static AMD64CondCode iselCondCode        ( ISelEnv* env, const IRExpr* e );

static HReg          iselDblExpr_wrk     ( ISelEnv* env, const IRExpr* e );
static HReg          iselDblExpr         ( ISelEnv* env, const IRExpr* e );

static HReg          iselFltExpr_wrk     ( ISelEnv* env, const IRExpr* e );
static HReg          iselFltExpr         ( ISelEnv* env, const IRExpr* e );

static HReg          iselVecExpr_wrk     ( ISelEnv* env, const IRExpr* e );
static HReg          iselVecExpr         ( ISelEnv* env, const IRExpr* e );

static void          iselDVecExpr_wrk ( /*OUT*/HReg* rHi, HReg* rLo, 
                                        ISelEnv* env, const IRExpr* e );
static void          iselDVecExpr     ( /*OUT*/HReg* rHi, HReg* rLo, 
                                        ISelEnv* env, const IRExpr* e );


/*---------------------------------------------------------*/
/*--- ISEL: Misc helpers                                ---*/
/*---------------------------------------------------------*/

static Bool sane_AMode ( AMD64AMode* am )
{
   switch (am->tag) {
      case Aam_IR:
         return 
            toBool( hregClass(am->Aam.IR.reg) == HRcInt64
                    && (hregIsVirtual(am->Aam.IR.reg)
                        || sameHReg(am->Aam.IR.reg, hregAMD64_RBP())) );
      case Aam_IRRS:
         return 
            toBool( hregClass(am->Aam.IRRS.base) == HRcInt64
                    && hregIsVirtual(am->Aam.IRRS.base)
                    && hregClass(am->Aam.IRRS.index) == HRcInt64
                    && hregIsVirtual(am->Aam.IRRS.index) );
      default:
        vpanic("sane_AMode: unknown amd64 amode tag");
   }
}


/* Can the lower 32 bits be signedly widened to produce the whole
   64-bit value?  In other words, are the top 33 bits either all 0 or
   all 1 ? */
static Bool fitsIn32Bits ( ULong x )
{
   Long y1;
   y1 = x << 32;
   y1 >>=/*s*/ 32;
   return toBool(x == y1);
}

/* Is this a 64-bit zero expression? */

static Bool isZeroU64 ( const IRExpr* e )
{
   return e->tag == Iex_Const
          && e->Iex.Const.con->tag == Ico_U64
          && e->Iex.Const.con->Ico.U64 == 0ULL;
}

static Bool isZeroU32 ( const IRExpr* e )
{
   return e->tag == Iex_Const
          && e->Iex.Const.con->tag == Ico_U32
          && e->Iex.Const.con->Ico.U32 == 0;
}

/* Are both args atoms and the same?  This is copy of eqIRAtom
   that omits the assertions that the args are indeed atoms. */

static Bool areAtomsAndEqual ( const IRExpr* a1, const IRExpr* a2 )
{
   if (a1->tag == Iex_RdTmp && a2->tag == Iex_RdTmp)
      return toBool(a1->Iex.RdTmp.tmp == a2->Iex.RdTmp.tmp);
   if (a1->tag == Iex_Const && a2->tag == Iex_Const)
      return eqIRConst(a1->Iex.Const.con, a2->Iex.Const.con);
   return False;
}

/* Make a int reg-reg move. */

static AMD64Instr* mk_iMOVsd_RR ( HReg src, HReg dst )
{
   vassert(hregClass(src) == HRcInt64);
   vassert(hregClass(dst) == HRcInt64);
   return AMD64Instr_Alu64R(Aalu_MOV, AMD64RMI_Reg(src), dst);
}

/* Make a vector (128 bit) reg-reg move. */

static AMD64Instr* mk_vMOVsd_RR ( HReg src, HReg dst )
{
   vassert(hregClass(src) == HRcVec128);
   vassert(hregClass(dst) == HRcVec128);
   return AMD64Instr_SseReRg(Asse_MOV, src, dst);
}

/* Advance/retreat %rsp by n. */

static void add_to_rsp ( ISelEnv* env, Int n )
{
   vassert(n > 0 && n < 256 && (n%8) == 0);
   addInstr(env, 
            AMD64Instr_Alu64R(Aalu_ADD, AMD64RMI_Imm(n), 
                                        hregAMD64_RSP()));
}

static void sub_from_rsp ( ISelEnv* env, Int n )
{
   vassert(n > 0 && n < 256 && (n%8) == 0);
   addInstr(env, 
            AMD64Instr_Alu64R(Aalu_SUB, AMD64RMI_Imm(n), 
                                        hregAMD64_RSP()));
}

/* Push 64-bit constants on the stack. */
static void push_uimm64( ISelEnv* env, ULong uimm64 )
{
   /* If uimm64 can be expressed as the sign extension of its
      lower 32 bits, we can do it the easy way. */
   Long simm64 = (Long)uimm64;
   if ( simm64 == ((Long)(uimm64 << 32) >> 32) ) {
      addInstr( env, AMD64Instr_Push(AMD64RMI_Imm( (UInt)uimm64 )) );
   } else {
      HReg tmp = newVRegI(env);
      addInstr( env, AMD64Instr_Imm64(uimm64, tmp) );
      addInstr( env, AMD64Instr_Push(AMD64RMI_Reg(tmp)) );
   }
}


/* Used only in doHelperCall.  If possible, produce a single
   instruction which computes 'e' into 'dst'.  If not possible, return
   NULL. */

static AMD64Instr* iselIntExpr_single_instruction ( ISelEnv* env,
                                                    HReg     dst,
                                                    IRExpr*  e )
{
   /* Per comments in doHelperCall below, appearance of
      Iex_VECRET implies ill-formed IR. */
   vassert(e->tag != Iex_VECRET);

   /* In this case we give out a copy of the BaseBlock pointer. */
   if (UNLIKELY(e->tag == Iex_GSPTR)) {
      return mk_iMOVsd_RR( hregAMD64_RBP(), dst );
   }

   vassert(typeOfIRExpr(env->type_env, e) == Ity_I64);

   if (e->tag == Iex_Const) {
      vassert(e->Iex.Const.con->tag == Ico_U64);
      if (fitsIn32Bits(e->Iex.Const.con->Ico.U64)) {
         return AMD64Instr_Alu64R(
                   Aalu_MOV,
                   AMD64RMI_Imm(toUInt(e->Iex.Const.con->Ico.U64)),
                   dst
                );
      } else {
         return AMD64Instr_Imm64(e->Iex.Const.con->Ico.U64, dst);
      }
   }

   if (e->tag == Iex_RdTmp) {
      HReg src = lookupIRTemp(env, e->Iex.RdTmp.tmp);
      return mk_iMOVsd_RR(src, dst);
   }

   if (e->tag == Iex_Get) {
      vassert(e->Iex.Get.ty == Ity_I64);
      return AMD64Instr_Alu64R(
                Aalu_MOV,
                AMD64RMI_Mem(
                   AMD64AMode_IR(e->Iex.Get.offset,
                                 hregAMD64_RBP())),
                dst);
   }

   if (e->tag == Iex_Unop 
       && e->Iex.Unop.op == Iop_32Uto64 
       && e->Iex.Unop.arg->tag == Iex_RdTmp) {
      HReg src = lookupIRTemp(env, e->Iex.Unop.arg->Iex.RdTmp.tmp);
      return AMD64Instr_MovxLQ(False, src, dst);
   }

   if (0) { ppIRExpr(e); vex_printf("\n"); }

   return NULL;
}


/* Do a complete function call.  |guard| is a Ity_Bit expression
   indicating whether or not the call happens.  If guard==NULL, the
   call is unconditional.  |retloc| is set to indicate where the
   return value is after the call.  The caller (of this fn) must
   generate code to add |stackAdjustAfterCall| to the stack pointer
   after the call is done. */

static
void doHelperCall ( /*OUT*/UInt*   stackAdjustAfterCall,
                    /*OUT*/RetLoc* retloc,
                    ISelEnv* env,
                    IRExpr* guard,
                    IRCallee* cee, IRType retTy, IRExpr** args )
{
   AMD64CondCode cc;
   HReg          argregs[6];
   HReg          tmpregs[6];
   AMD64Instr*   fastinstrs[6];
   UInt          n_args, i;

   /* Set default returns.  We'll update them later if needed. */
   *stackAdjustAfterCall = 0;
   *retloc               = mk_RetLoc_INVALID();

   /* These are used for cross-checking that IR-level constraints on
      the use of IRExpr_VECRET() and IRExpr_GSPTR() are observed. */
   UInt nVECRETs = 0;
   UInt nGSPTRs  = 0;

   /* Marshal args for a call and do the call.

      This function only deals with a tiny set of possibilities, which
      cover all helpers in practice.  The restrictions are that only
      arguments in registers are supported, hence only 6x64 integer
      bits in total can be passed.  In fact the only supported arg
      type is I64.

      The return type can be I{64,32,16,8} or V{128,256}.  In the
      latter two cases, it is expected that |args| will contain the
      special node IRExpr_VECRET(), in which case this routine
      generates code to allocate space on the stack for the vector
      return value.  Since we are not passing any scalars on the
      stack, it is enough to preallocate the return space before
      marshalling any arguments, in this case.

      |args| may also contain IRExpr_GSPTR(), in which case the
      value in %rbp is passed as the corresponding argument.

      Generating code which is both efficient and correct when
      parameters are to be passed in registers is difficult, for the
      reasons elaborated in detail in comments attached to
      doHelperCall() in priv/host-x86/isel.c.  Here, we use a variant
      of the method described in those comments.

      The problem is split into two cases: the fast scheme and the
      slow scheme.  In the fast scheme, arguments are computed
      directly into the target (real) registers.  This is only safe
      when we can be sure that computation of each argument will not
      trash any real registers set by computation of any other
      argument.

      In the slow scheme, all args are first computed into vregs, and
      once they are all done, they are moved to the relevant real
      regs.  This always gives correct code, but it also gives a bunch
      of vreg-to-rreg moves which are usually redundant but are hard
      for the register allocator to get rid of.

      To decide which scheme to use, all argument expressions are
      first examined.  If they are all so simple that it is clear they
      will be evaluated without use of any fixed registers, use the
      fast scheme, else use the slow scheme.  Note also that only
      unconditional calls may use the fast scheme, since having to
      compute a condition expression could itself trash real
      registers.  Note that for simplicity, in the case where
      IRExpr_VECRET() is present, we use the slow scheme.  This is
      motivated by the desire to avoid any possible complexity
      w.r.t. nested calls.

      Note this requires being able to examine an expression and
      determine whether or not evaluation of it might use a fixed
      register.  That requires knowledge of how the rest of this insn
      selector works.  Currently just the following 3 are regarded as
      safe -- hopefully they cover the majority of arguments in
      practice: IRExpr_Tmp IRExpr_Const IRExpr_Get.
   */

   /* Note that the cee->regparms field is meaningless on AMD64 host
      (since there is only one calling convention) and so we always
      ignore it. */
   n_args = 0;
   for (i = 0; args[i]; i++)
      n_args++;

   if (n_args > 6)
      vpanic("doHelperCall(AMD64): cannot currently handle > 6 args");

   argregs[0] = hregAMD64_RDI();
   argregs[1] = hregAMD64_RSI();
   argregs[2] = hregAMD64_RDX();
   argregs[3] = hregAMD64_RCX();
   argregs[4] = hregAMD64_R8();
   argregs[5] = hregAMD64_R9();

   tmpregs[0] = tmpregs[1] = tmpregs[2] =
   tmpregs[3] = tmpregs[4] = tmpregs[5] = INVALID_HREG;

   fastinstrs[0] = fastinstrs[1] = fastinstrs[2] =
   fastinstrs[3] = fastinstrs[4] = fastinstrs[5] = NULL;

   /* First decide which scheme (slow or fast) is to be used.  First
      assume the fast scheme, and select slow if any contraindications
      (wow) appear. */

   /* We'll need space on the stack for the return value.  Avoid
      possible complications with nested calls by using the slow
      scheme. */
   if (retTy == Ity_V128 || retTy == Ity_V256)
      goto slowscheme;

   if (guard) {
      if (guard->tag == Iex_Const 
          && guard->Iex.Const.con->tag == Ico_U1
          && guard->Iex.Const.con->Ico.U1 == True) {
         /* unconditional */
      } else {
         /* Not manifestly unconditional -- be conservative. */
         goto slowscheme;
      }
   }

   /* Ok, let's try for the fast scheme.  If it doesn't pan out, we'll
      use the slow scheme.  Because this is tentative, we can't call
      addInstr (that is, commit to) any instructions until we're
      handled all the arguments.  So park the resulting instructions
      in a buffer and emit that if we're successful. */

   /* FAST SCHEME */
   /* In this loop, we process args that can be computed into the
      destination (real) register with a single instruction, without
      using any fixed regs.  That also includes IRExpr_GSPTR(), but
      not IRExpr_VECRET().  Indeed, if the IR is well-formed, we can
      never see IRExpr_VECRET() at this point, since the return-type
      check above should ensure all those cases use the slow scheme
      instead. */
   vassert(n_args >= 0 && n_args <= 6);
   for (i = 0; i < n_args; i++) {
      IRExpr* arg = args[i];
      if (LIKELY(!is_IRExpr_VECRET_or_GSPTR(arg))) {
         vassert(typeOfIRExpr(env->type_env, args[i]) == Ity_I64);
      }
      fastinstrs[i] 
         = iselIntExpr_single_instruction( env, argregs[i], args[i] );
      if (fastinstrs[i] == NULL)
         goto slowscheme;
   }

   /* Looks like we're in luck.  Emit the accumulated instructions and
      move on to doing the call itself. */
   for (i = 0; i < n_args; i++)
      addInstr(env, fastinstrs[i]);

   /* Fast scheme only applies for unconditional calls.  Hence: */
   cc = Acc_ALWAYS;

   goto handle_call;


   /* SLOW SCHEME; move via temporaries */
  slowscheme:
   {}
#  if 0 /* debug only */
   if (n_args > 0) {for (i = 0; args[i]; i++) {
   ppIRExpr(args[i]); vex_printf(" "); }
   vex_printf("\n");}
#  endif

   /* If we have a vector return type, allocate a place for it on the
      stack and record its address. */
   HReg r_vecRetAddr = INVALID_HREG;
   if (retTy == Ity_V128) {
      r_vecRetAddr = newVRegI(env);
      sub_from_rsp(env, 16);
      addInstr(env, mk_iMOVsd_RR( hregAMD64_RSP(), r_vecRetAddr ));
   }
   else if (retTy == Ity_V256) {
      r_vecRetAddr = newVRegI(env);
      sub_from_rsp(env, 32);
      addInstr(env, mk_iMOVsd_RR( hregAMD64_RSP(), r_vecRetAddr ));
   }

   vassert(n_args >= 0 && n_args <= 6);
   for (i = 0; i < n_args; i++) {
      IRExpr* arg = args[i];
      if (UNLIKELY(arg->tag == Iex_GSPTR)) {
         tmpregs[i] = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR( hregAMD64_RBP(), tmpregs[i]));
         nGSPTRs++;
      }
      else if (UNLIKELY(arg->tag == Iex_VECRET)) {
         /* We stashed the address of the return slot earlier, so just
            retrieve it now. */
         vassert(!hregIsInvalid(r_vecRetAddr));
         tmpregs[i] = r_vecRetAddr;
         nVECRETs++;
      }
      else {
         vassert(typeOfIRExpr(env->type_env, args[i]) == Ity_I64);
         tmpregs[i] = iselIntExpr_R(env, args[i]);
      }
   }

   /* Now we can compute the condition.  We can't do it earlier
      because the argument computations could trash the condition
      codes.  Be a bit clever to handle the common case where the
      guard is 1:Bit. */
   cc = Acc_ALWAYS;
   if (guard) {
      if (guard->tag == Iex_Const 
          && guard->Iex.Const.con->tag == Ico_U1
          && guard->Iex.Const.con->Ico.U1 == True) {
         /* unconditional -- do nothing */
      } else {
         cc = iselCondCode( env, guard );
      }
   }

   /* Move the args to their final destinations. */
   for (i = 0; i < n_args; i++) {
      /* None of these insns, including any spill code that might
         be generated, may alter the condition codes. */
      addInstr( env, mk_iMOVsd_RR( tmpregs[i], argregs[i] ) );
   }


   /* Do final checks, set the return values, and generate the call
      instruction proper. */
  handle_call:

   if (retTy == Ity_V128 || retTy == Ity_V256) {
      vassert(nVECRETs == 1);
   } else {
      vassert(nVECRETs == 0);
   }

   vassert(nGSPTRs == 0 || nGSPTRs == 1);

   vassert(*stackAdjustAfterCall == 0);
   vassert(is_RetLoc_INVALID(*retloc));
   switch (retTy) {
         case Ity_INVALID:
            /* Function doesn't return a value. */
            *retloc = mk_RetLoc_simple(RLPri_None);
            break;
         case Ity_I64: case Ity_I32: case Ity_I16: case Ity_I8:
            *retloc = mk_RetLoc_simple(RLPri_Int);
            break;
         case Ity_V128:
            *retloc = mk_RetLoc_spRel(RLPri_V128SpRel, 0);
            *stackAdjustAfterCall = 16;
            break;
         case Ity_V256:
            *retloc = mk_RetLoc_spRel(RLPri_V256SpRel, 0);
            *stackAdjustAfterCall = 32;
            break;
         default:
            /* IR can denote other possible return types, but we don't
               handle those here. */
           vassert(0);
   }

   /* Finally, generate the call itself.  This needs the *retloc value
      set in the switch above, which is why it's at the end. */
   addInstr(env,
            AMD64Instr_Call(cc, (Addr)cee->addr, n_args, *retloc));
}


/* Given a guest-state array descriptor, an index expression and a
   bias, generate an AMD64AMode holding the relevant guest state
   offset. */

static
AMD64AMode* genGuestArrayOffset ( ISelEnv* env, IRRegArray* descr, 
                                  IRExpr* off, Int bias )
{
   HReg tmp, roff;
   Int  elemSz = sizeofIRType(descr->elemTy);
   Int  nElems = descr->nElems;

   /* Throw out any cases not generated by an amd64 front end.  In
      theory there might be a day where we need to handle them -- if
      we ever run non-amd64-guest on amd64 host. */

   if (nElems != 8 || (elemSz != 1 && elemSz != 8))
      vpanic("genGuestArrayOffset(amd64 host)");

   /* Compute off into a reg, %off.  Then return:

         movq %off, %tmp
         addq $bias, %tmp  (if bias != 0)
         andq %tmp, 7
         ... base(%rbp, %tmp, shift) ...
   */
   tmp  = newVRegI(env);
   roff = iselIntExpr_R(env, off);
   addInstr(env, mk_iMOVsd_RR(roff, tmp));
   if (bias != 0) {
      /* Make sure the bias is sane, in the sense that there are
         no significant bits above bit 30 in it. */
      vassert(-10000 < bias && bias < 10000);
      addInstr(env, 
               AMD64Instr_Alu64R(Aalu_ADD, AMD64RMI_Imm(bias), tmp));
   }
   addInstr(env, 
            AMD64Instr_Alu64R(Aalu_AND, AMD64RMI_Imm(7), tmp));
   vassert(elemSz == 1 || elemSz == 8);
   return
      AMD64AMode_IRRS( descr->base, hregAMD64_RBP(), tmp,
                                    elemSz==8 ? 3 : 0);
}


/* Set the SSE unit's rounding mode to default (%mxcsr = 0x1F80) */
static
void set_SSE_rounding_default ( ISelEnv* env )
{
   /* pushq $DEFAULT_MXCSR 
      ldmxcsr 0(%rsp)
      addq $8, %rsp
   */
   AMD64AMode* zero_rsp = AMD64AMode_IR(0, hregAMD64_RSP());
   addInstr(env, AMD64Instr_Push(AMD64RMI_Imm(DEFAULT_MXCSR)));
   addInstr(env, AMD64Instr_LdMXCSR(zero_rsp));
   add_to_rsp(env, 8);
}

/* Mess with the FPU's rounding mode: set to the default rounding mode
   (DEFAULT_FPUCW). */
static 
void set_FPU_rounding_default ( ISelEnv* env )
{
   /* movq $DEFAULT_FPUCW, -8(%rsp)
      fldcw -8(%esp)
   */
   AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
   addInstr(env, AMD64Instr_Alu64M(
                    Aalu_MOV, AMD64RI_Imm(DEFAULT_FPUCW), m8_rsp));
   addInstr(env, AMD64Instr_A87LdCW(m8_rsp));
}


/* Mess with the SSE unit's rounding mode: 'mode' is an I32-typed
   expression denoting a value in the range 0 .. 3, indicating a round
   mode encoded as per type IRRoundingMode.  Set the SSE machinery to
   have the same rounding.
*/
static
void set_SSE_rounding_mode ( ISelEnv* env, IRExpr* mode )
{
   /* Note: this sequence only makes sense because DEFAULT_MXCSR has
      both rounding bits == 0.  If that wasn't the case, we couldn't
      create a new rounding field simply by ORing the new value into
      place. */

   /* movq $3, %reg
      andq [[mode]], %reg  -- shouldn't be needed; paranoia
      shlq $13, %reg
      orq $DEFAULT_MXCSR, %reg
      pushq %reg
      ldmxcsr 0(%esp)
      addq $8, %rsp
   */      
   HReg        reg      = newVRegI(env);
   AMD64AMode* zero_rsp = AMD64AMode_IR(0, hregAMD64_RSP());
   addInstr(env, AMD64Instr_Alu64R(Aalu_MOV, AMD64RMI_Imm(3), reg));
   addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                   iselIntExpr_RMI(env, mode), reg));
   addInstr(env, AMD64Instr_Sh64(Ash_SHL, 13, reg));
   addInstr(env, AMD64Instr_Alu64R(
                    Aalu_OR, AMD64RMI_Imm(DEFAULT_MXCSR), reg));
   addInstr(env, AMD64Instr_Push(AMD64RMI_Reg(reg)));
   addInstr(env, AMD64Instr_LdMXCSR(zero_rsp));
   add_to_rsp(env, 8);
}


/* Mess with the FPU's rounding mode: 'mode' is an I32-typed
   expression denoting a value in the range 0 .. 3, indicating a round
   mode encoded as per type IRRoundingMode.  Set the x87 FPU to have
   the same rounding.
*/
static
void set_FPU_rounding_mode ( ISelEnv* env, IRExpr* mode )
{
   HReg rrm  = iselIntExpr_R(env, mode);
   HReg rrm2 = newVRegI(env);
   AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());

   /* movq  %rrm, %rrm2
      andq  $3, %rrm2   -- shouldn't be needed; paranoia
      shlq  $10, %rrm2
      orq   $DEFAULT_FPUCW, %rrm2
      movq  %rrm2, -8(%rsp)
      fldcw -8(%esp)
   */
   addInstr(env, mk_iMOVsd_RR(rrm, rrm2));
   addInstr(env, AMD64Instr_Alu64R(Aalu_AND, AMD64RMI_Imm(3), rrm2));
   addInstr(env, AMD64Instr_Sh64(Ash_SHL, 10, rrm2));
   addInstr(env, AMD64Instr_Alu64R(Aalu_OR, 
                                   AMD64RMI_Imm(DEFAULT_FPUCW), rrm2));
   addInstr(env, AMD64Instr_Alu64M(Aalu_MOV, 
                                   AMD64RI_Reg(rrm2), m8_rsp));
   addInstr(env, AMD64Instr_A87LdCW(m8_rsp));
}


/* Generate all-zeroes into a new vector register.
*/
static HReg generate_zeroes_V128 ( ISelEnv* env )
{
   HReg dst = newVRegV(env);
   addInstr(env, AMD64Instr_SseReRg(Asse_XOR, dst, dst));
   return dst;
}

/* Generate all-ones into a new vector register.
*/
static HReg generate_ones_V128 ( ISelEnv* env )
{
   HReg dst = newVRegV(env);
   addInstr(env, AMD64Instr_SseReRg(Asse_CMPEQ32, dst, dst));
   return dst;
}


/* Generate !src into a new vector register.  Amazing that there isn't
   a less crappy way to do this.
*/
static HReg do_sse_NotV128 ( ISelEnv* env, HReg src )
{
   HReg dst = generate_ones_V128(env);
   addInstr(env, AMD64Instr_SseReRg(Asse_XOR, src, dst));
   return dst;
}


/* Expand the given byte into a 64-bit word, by cloning each bit
   8 times. */
static ULong bitmask8_to_bytemask64 ( UShort w8 )
{
   vassert(w8 == (w8 & 0xFF));
   ULong w64 = 0;
   Int i;
   for (i = 0; i < 8; i++) {
      if (w8 & (1<<i))
         w64 |= (0xFFULL << (8 * i));
   }
   return w64;
}


/*---------------------------------------------------------*/
/*--- ISEL: Integer expressions (64/32/16/8 bit)        ---*/
/*---------------------------------------------------------*/

/* Select insns for an integer-typed expression, and add them to the
   code list.  Return a reg holding the result.  This reg will be a
   virtual register.  THE RETURNED REG MUST NOT BE MODIFIED.  If you
   want to modify it, ask for a new vreg, copy it in there, and modify
   the copy.  The register allocator will do its best to map both
   vregs to the same real register, so the copies will often disappear
   later in the game.

   This should handle expressions of 64, 32, 16 and 8-bit type.  All
   results are returned in a 64-bit register.  For 32-, 16- and 8-bit
   expressions, the upper 32/48/56 bits are arbitrary, so you should
   mask or sign extend partial values if necessary.
*/

static HReg iselIntExpr_R ( ISelEnv* env, const IRExpr* e )
{
   HReg r = iselIntExpr_R_wrk(env, e);
   /* sanity checks ... */
#  if 0
   vex_printf("\niselIntExpr_R: "); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(r) == HRcInt64);
   vassert(hregIsVirtual(r));
   return r;
}

/* DO NOT CALL THIS DIRECTLY ! */
static HReg iselIntExpr_R_wrk ( ISelEnv* env, const IRExpr* e )
{
   MatchInfo mi;
   DECLARE_PATTERN(p_1Uto8_64to1);
   DECLARE_PATTERN(p_LDle8_then_8Uto64);
   DECLARE_PATTERN(p_LDle16_then_16Uto64);

   IRType ty = typeOfIRExpr(env->type_env,e);
   switch (ty) {
      case Ity_I64: case Ity_I32: case Ity_I16: case Ity_I8: break;
      default: vassert(0);
   }

   switch (e->tag) {

   /* --------- TEMP --------- */
   case Iex_RdTmp: {
      return lookupIRTemp(env, e->Iex.RdTmp.tmp);
   }

   /* --------- LOAD --------- */
   case Iex_Load: {
      HReg dst = newVRegI(env);
      AMD64AMode* amode = iselIntExpr_AMode ( env, e->Iex.Load.addr );

      /* We can't handle big-endian loads, nor load-linked. */
      if (e->Iex.Load.end != Iend_LE)
         goto irreducible;

      if (ty == Ity_I64) {
         addInstr(env, AMD64Instr_Alu64R(Aalu_MOV,
                                         AMD64RMI_Mem(amode), dst) );
         return dst;
      }
      if (ty == Ity_I32) {
         addInstr(env, AMD64Instr_LoadEX(4,False,amode,dst));
         return dst;
      }
      if (ty == Ity_I16) {
         addInstr(env, AMD64Instr_LoadEX(2,False,amode,dst));
         return dst;
      }
      if (ty == Ity_I8) {
         addInstr(env, AMD64Instr_LoadEX(1,False,amode,dst));
         return dst;
      }
      break;
   }

   /* --------- BINARY OP --------- */
   case Iex_Binop: {
      AMD64AluOp   aluOp;
      AMD64ShiftOp shOp;

      /* Pattern: Sub64(0,x) */
      /*     and: Sub32(0,x) */
      if ((e->Iex.Binop.op == Iop_Sub64 && isZeroU64(e->Iex.Binop.arg1))
          || (e->Iex.Binop.op == Iop_Sub32 && isZeroU32(e->Iex.Binop.arg1))) {
         HReg dst = newVRegI(env);
         HReg reg = iselIntExpr_R(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(reg,dst));
         addInstr(env, AMD64Instr_Unary64(Aun_NEG,dst));
         return dst;
      }

      /* Is it an addition or logical style op? */
      switch (e->Iex.Binop.op) {
         case Iop_Add8: case Iop_Add16: case Iop_Add32: case Iop_Add64: 
            aluOp = Aalu_ADD; break;
         case Iop_Sub8: case Iop_Sub16: case Iop_Sub32: case Iop_Sub64:
            aluOp = Aalu_SUB; break;
         case Iop_And8: case Iop_And16: case Iop_And32: case Iop_And64: 
            aluOp = Aalu_AND; break;
         case Iop_Or8:  case Iop_Or16:  case Iop_Or32:  case Iop_Or64: 
            aluOp = Aalu_OR; break;
         case Iop_Xor8: case Iop_Xor16: case Iop_Xor32: case Iop_Xor64: 
            aluOp = Aalu_XOR; break;
         case Iop_Mul16: case Iop_Mul32: case Iop_Mul64:
            aluOp = Aalu_MUL; break;
         default:
            aluOp = Aalu_INVALID; break;
      }
      /* For commutative ops we assume any literal
         values are on the second operand. */
      if (aluOp != Aalu_INVALID) {
         HReg dst      = newVRegI(env);
         HReg reg      = iselIntExpr_R(env, e->Iex.Binop.arg1);
         AMD64RMI* rmi = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(reg,dst));
         addInstr(env, AMD64Instr_Alu64R(aluOp, rmi, dst));
         return dst;
      }

      /* Perhaps a shift op? */
      switch (e->Iex.Binop.op) {
         case Iop_Shl64: case Iop_Shl32: case Iop_Shl16: case Iop_Shl8:
            shOp = Ash_SHL; break;
         case Iop_Shr64: case Iop_Shr32: case Iop_Shr16: case Iop_Shr8: 
            shOp = Ash_SHR; break;
         case Iop_Sar64: case Iop_Sar32: case Iop_Sar16: case Iop_Sar8: 
            shOp = Ash_SAR; break;
         default:
            shOp = Ash_INVALID; break;
      }
      if (shOp != Ash_INVALID) {
         HReg dst = newVRegI(env);

         /* regL = the value to be shifted */
         HReg regL   = iselIntExpr_R(env, e->Iex.Binop.arg1);
         addInstr(env, mk_iMOVsd_RR(regL,dst));

         /* Do any necessary widening for 32/16/8 bit operands */
         switch (e->Iex.Binop.op) {
            case Iop_Shr64: case Iop_Shl64: case Iop_Sar64: 
               break;
            case Iop_Shl32: case Iop_Shl16: case Iop_Shl8:
               break;
            case Iop_Shr8:
               addInstr(env, AMD64Instr_Alu64R(
                                Aalu_AND, AMD64RMI_Imm(0xFF), dst));
               break;
            case Iop_Shr16:
               addInstr(env, AMD64Instr_Alu64R(
                                Aalu_AND, AMD64RMI_Imm(0xFFFF), dst));
               break;
            case Iop_Shr32:
               addInstr(env, AMD64Instr_MovxLQ(False, dst, dst));
               break;
            case Iop_Sar8:
               addInstr(env, AMD64Instr_Sh64(Ash_SHL, 56, dst));
               addInstr(env, AMD64Instr_Sh64(Ash_SAR, 56, dst));
               break;
            case Iop_Sar16:
               addInstr(env, AMD64Instr_Sh64(Ash_SHL, 48, dst));
               addInstr(env, AMD64Instr_Sh64(Ash_SAR, 48, dst));
               break;
            case Iop_Sar32:
               addInstr(env, AMD64Instr_MovxLQ(True, dst, dst));
               break;
            default: 
               ppIROp(e->Iex.Binop.op);
               vassert(0);
         }

         /* Now consider the shift amount.  If it's a literal, we
            can do a much better job than the general case. */
         if (e->Iex.Binop.arg2->tag == Iex_Const) {
            /* assert that the IR is well-typed */
            Int nshift;
            vassert(e->Iex.Binop.arg2->Iex.Const.con->tag == Ico_U8);
            nshift = e->Iex.Binop.arg2->Iex.Const.con->Ico.U8;
            vassert(nshift >= 0);
            if (nshift > 0)
               /* Can't allow nshift==0 since that means %cl */
               addInstr(env, AMD64Instr_Sh64(shOp, nshift, dst));
         } else {
            /* General case; we have to force the amount into %cl. */
            HReg regR = iselIntExpr_R(env, e->Iex.Binop.arg2);
            addInstr(env, mk_iMOVsd_RR(regR,hregAMD64_RCX()));
            addInstr(env, AMD64Instr_Sh64(shOp, 0/* %cl */, dst));
         }
         return dst;
      }

      /* Handle misc other scalar ops. */
      if (e->Iex.Binop.op == Iop_Max32U) {
         HReg src1 = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg dst  = newVRegI(env);
         HReg src2 = iselIntExpr_R(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(src1, dst));
         addInstr(env, AMD64Instr_Alu32R(Aalu_CMP, AMD64RMI_Reg(src2), dst));
         addInstr(env, AMD64Instr_CMov64(Acc_B, src2, dst));
         return dst;
      }

      if (e->Iex.Binop.op == Iop_DivModS64to32
          || e->Iex.Binop.op == Iop_DivModU64to32) {
         /* 64 x 32 -> (32(rem),32(div)) division */
         /* Get the 64-bit operand into edx:eax, and the other into
            any old R/M. */
         HReg      rax     = hregAMD64_RAX();
         HReg      rdx     = hregAMD64_RDX();
         HReg      dst     = newVRegI(env);
         Bool      syned   = toBool(e->Iex.Binop.op == Iop_DivModS64to32);
         AMD64RM*  rmRight = iselIntExpr_RM(env, e->Iex.Binop.arg2);
         /* Compute the left operand into a reg, and then 
            put the top half in edx and the bottom in eax. */
         HReg left64 = iselIntExpr_R(env, e->Iex.Binop.arg1);
         addInstr(env, mk_iMOVsd_RR(left64, rdx));
         addInstr(env, mk_iMOVsd_RR(left64, rax));
         addInstr(env, AMD64Instr_Sh64(Ash_SHR, 32, rdx));
         addInstr(env, AMD64Instr_Div(syned, 4, rmRight));
         addInstr(env, AMD64Instr_MovxLQ(False, rdx, rdx));
         addInstr(env, AMD64Instr_MovxLQ(False, rax, rax));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, 32, rdx));
         addInstr(env, mk_iMOVsd_RR(rax, dst));
         addInstr(env, AMD64Instr_Alu64R(Aalu_OR, AMD64RMI_Reg(rdx), dst));
         return dst;
      }

      if (e->Iex.Binop.op == Iop_32HLto64) {
         HReg hi32  = newVRegI(env);
         HReg lo32  = newVRegI(env);
         HReg hi32s = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg lo32s = iselIntExpr_R(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(hi32s, hi32));
         addInstr(env, mk_iMOVsd_RR(lo32s, lo32));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, 32, hi32));
         addInstr(env, AMD64Instr_MovxLQ(False, lo32, lo32));
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_OR, AMD64RMI_Reg(lo32), hi32));
         return hi32;
      }

      if (e->Iex.Binop.op == Iop_16HLto32) {
         HReg hi16  = newVRegI(env);
         HReg lo16  = newVRegI(env);
         HReg hi16s = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg lo16s = iselIntExpr_R(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(hi16s, hi16));
         addInstr(env, mk_iMOVsd_RR(lo16s, lo16));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, 16, hi16));
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_AND, AMD64RMI_Imm(0xFFFF), lo16));
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_OR, AMD64RMI_Reg(lo16), hi16));
         return hi16;
      }

      if (e->Iex.Binop.op == Iop_8HLto16) {
         HReg hi8  = newVRegI(env);
         HReg lo8  = newVRegI(env);
         HReg hi8s = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg lo8s = iselIntExpr_R(env, e->Iex.Binop.arg2);
         addInstr(env, mk_iMOVsd_RR(hi8s, hi8));
         addInstr(env, mk_iMOVsd_RR(lo8s, lo8));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, 8, hi8));
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_AND, AMD64RMI_Imm(0xFF), lo8));
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_OR, AMD64RMI_Reg(lo8), hi8));
         return hi8;
      }

      if (e->Iex.Binop.op == Iop_MullS32
          || e->Iex.Binop.op == Iop_MullS16
          || e->Iex.Binop.op == Iop_MullS8
          || e->Iex.Binop.op == Iop_MullU32 
          || e->Iex.Binop.op == Iop_MullU16 
          || e->Iex.Binop.op == Iop_MullU8) {
         HReg a32   = newVRegI(env);
         HReg b32   = newVRegI(env);
         HReg a32s  = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg b32s  = iselIntExpr_R(env, e->Iex.Binop.arg2);
         Int          shift  = 0;
         AMD64ShiftOp shr_op = Ash_SHR;
         switch (e->Iex.Binop.op) {
            case Iop_MullS32: shr_op = Ash_SAR; shift = 32; break;
            case Iop_MullS16: shr_op = Ash_SAR; shift = 48; break;
            case Iop_MullS8:  shr_op = Ash_SAR; shift = 56; break;
            case Iop_MullU32: shr_op = Ash_SHR; shift = 32; break;
            case Iop_MullU16: shr_op = Ash_SHR; shift = 48; break;
            case Iop_MullU8:  shr_op = Ash_SHR; shift = 56; break;
            default: vassert(0);
         }

         addInstr(env, mk_iMOVsd_RR(a32s, a32));
         addInstr(env, mk_iMOVsd_RR(b32s, b32));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, shift, a32));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, shift, b32));
         addInstr(env, AMD64Instr_Sh64(shr_op,  shift, a32));
         addInstr(env, AMD64Instr_Sh64(shr_op,  shift, b32));
         addInstr(env, AMD64Instr_Alu64R(Aalu_MUL, AMD64RMI_Reg(a32), b32));
         return b32;
      }

      if (e->Iex.Binop.op == Iop_CmpF64) {
         HReg fL = iselDblExpr(env, e->Iex.Binop.arg1);
         HReg fR = iselDblExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegI(env);
         addInstr(env, AMD64Instr_SseUComIS(8,fL,fR,dst));
         /* Mask out irrelevant parts of the result so as to conform
            to the CmpF64 definition. */
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND, AMD64RMI_Imm(0x45), dst));
         return dst;
      }

      if (e->Iex.Binop.op == Iop_F64toI32S
          || e->Iex.Binop.op == Iop_F64toI64S) {
         Int  szD = e->Iex.Binop.op==Iop_F64toI32S ? 4 : 8;
         HReg rf  = iselDblExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegI(env);
         set_SSE_rounding_mode( env, e->Iex.Binop.arg1 );
         addInstr(env, AMD64Instr_SseSF2SI( 8, szD, rf, dst ));
         set_SSE_rounding_default(env);
         return dst;
      }

      /* Deal with 64-bit SIMD binary ops.  For the most part these are doable
         by using the equivalent 128-bit operation and ignoring the upper half
         of the result. */
      AMD64SseOp op = Asse_INVALID;
      Bool arg1isEReg = False;
      Bool preShift32R = False;
      switch (e->Iex.Binop.op) {
         // The following 3 could be done with 128 bit insns too, but
         // first require the inputs to be reformatted.
         //case Iop_QNarrowBin32Sto16Sx4:
         //op = Asse_PACKSSD; arg1isEReg = True; break;
         //case Iop_QNarrowBin16Sto8Sx8:
         //op = Asse_PACKSSW; arg1isEReg = True; break;
         //case Iop_QNarrowBin16Sto8Ux8:
         //op = Asse_PACKUSW; arg1isEReg = True; break;

         case Iop_InterleaveHI8x8:
            op = Asse_UNPCKLB; arg1isEReg = True; preShift32R = True;
            break;
         case Iop_InterleaveHI16x4:
            op = Asse_UNPCKLW; arg1isEReg = True; preShift32R = True;
            break;
         case Iop_InterleaveHI32x2:
            op = Asse_UNPCKLD; arg1isEReg = True; preShift32R = True;
            break;
         case Iop_InterleaveLO8x8:
            op = Asse_UNPCKLB; arg1isEReg = True;
            break;
         case Iop_InterleaveLO16x4:
            op = Asse_UNPCKLW; arg1isEReg = True;
            break;
         case Iop_InterleaveLO32x2:
            op = Asse_UNPCKLD; arg1isEReg = True;
            break;

         case Iop_Add8x8:     op = Asse_ADD8;     break;
         case Iop_Add16x4:    op = Asse_ADD16;    break;
         case Iop_Add32x2:    op = Asse_ADD32;    break;
         case Iop_QAdd8Sx8:   op = Asse_QADD8S;   break;
         case Iop_QAdd16Sx4:  op = Asse_QADD16S;  break;
         case Iop_QAdd8Ux8:   op = Asse_QADD8U;   break;
         case Iop_QAdd16Ux4:  op = Asse_QADD16U;  break;
         case Iop_Avg8Ux8:    op = Asse_AVG8U;    break;
         case Iop_Avg16Ux4:   op = Asse_AVG16U;   break;
         case Iop_CmpEQ8x8:   op = Asse_CMPEQ8;   break;
         case Iop_CmpEQ16x4:  op = Asse_CMPEQ16;  break;
         case Iop_CmpEQ32x2:  op = Asse_CMPEQ32;  break;
         case Iop_CmpGT8Sx8:  op = Asse_CMPGT8S;  break;
         case Iop_CmpGT16Sx4: op = Asse_CMPGT16S; break;
         case Iop_CmpGT32Sx2: op = Asse_CMPGT32S; break;
         case Iop_Max16Sx4:   op = Asse_MAX16S;   break;
         case Iop_Max8Ux8:    op = Asse_MAX8U;    break;
         case Iop_Min16Sx4:   op = Asse_MIN16S;   break;
         case Iop_Min8Ux8:    op = Asse_MIN8U;    break;
         case Iop_MulHi16Ux4: op = Asse_MULHI16U; break;
         case Iop_MulHi16Sx4: op = Asse_MULHI16S; break;
         case Iop_Mul16x4:    op = Asse_MUL16;    break;
         case Iop_Sub8x8:     op = Asse_SUB8;     break;
         case Iop_Sub16x4:    op = Asse_SUB16;    break;
         case Iop_Sub32x2:    op = Asse_SUB32;    break;
         case Iop_QSub8Sx8:   op = Asse_QSUB8S;   break;
         case Iop_QSub16Sx4:  op = Asse_QSUB16S;  break;
         case Iop_QSub8Ux8:   op = Asse_QSUB8U;   break;
         case Iop_QSub16Ux4:  op = Asse_QSUB16U;  break;
         default: break;
      }
      if (op != Asse_INVALID) {
         /* This isn't pretty, but .. move each arg to the low half of an XMM
            register, do the operation on the whole register, and move the
            result back to an integer register. */
         const IRExpr* arg1 = e->Iex.Binop.arg1;
         const IRExpr* arg2 = e->Iex.Binop.arg2;
         vassert(typeOfIRExpr(env->type_env, arg1) == Ity_I64);
         vassert(typeOfIRExpr(env->type_env, arg2) == Ity_I64);
         HReg iarg1 = iselIntExpr_R(env, arg1);
         HReg iarg2 = iselIntExpr_R(env, arg2);
         HReg varg1 = newVRegV(env);
         HReg varg2 = newVRegV(env);
         HReg idst  = newVRegI(env);
         addInstr(env, AMD64Instr_SseMOVQ(iarg1, varg1, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseMOVQ(iarg2, varg2, True/*toXMM*/));
         if (arg1isEReg) {
            if (preShift32R) {
               addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 32, varg1));
               addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 32, varg2));
            }
            addInstr(env, AMD64Instr_SseReRg(op, varg1, varg2));
            addInstr(env, AMD64Instr_SseMOVQ(idst, varg2, False/*!toXMM*/));
         } else {
            vassert(!preShift32R);
            addInstr(env, AMD64Instr_SseReRg(op, varg2, varg1));
            addInstr(env, AMD64Instr_SseMOVQ(idst, varg1, False/*!toXMM*/));
         }
         return idst;
      }

      UInt laneBits = 0;
      op = Asse_INVALID;
      switch (e->Iex.Binop.op) {
         case Iop_ShlN16x4: laneBits = 16; op = Asse_SHL16; break;
         case Iop_ShlN32x2: laneBits = 32; op = Asse_SHL32; break;
         case Iop_SarN16x4: laneBits = 16; op = Asse_SAR16; break;
         case Iop_SarN32x2: laneBits = 32; op = Asse_SAR32; break;
         case Iop_ShrN16x4: laneBits = 16; op = Asse_SHR16; break;
         case Iop_ShrN32x2: laneBits = 32; op = Asse_SHR32; break;
         default: break;
      }
      if (op != Asse_INVALID) {
         const IRExpr* arg1 = e->Iex.Binop.arg1;
         const IRExpr* arg2 = e->Iex.Binop.arg2;
         vassert(typeOfIRExpr(env->type_env, arg1) == Ity_I64);
         vassert(typeOfIRExpr(env->type_env, arg2) == Ity_I8);
         HReg igreg = iselIntExpr_R(env, arg1);
         HReg vgreg = newVRegV(env);
         HReg idst  = newVRegI(env);
         addInstr(env, AMD64Instr_SseMOVQ(igreg, vgreg, True/*toXMM*/));
         /* If it's a shift by an in-range immediate, generate a single
            instruction. */
         if (arg2->tag == Iex_Const) {
            IRConst* c = arg2->Iex.Const.con;
            vassert(c->tag == Ico_U8);
            UInt shift = c->Ico.U8;
            if (shift < laneBits) {
               addInstr(env, AMD64Instr_SseShiftN(op, shift, vgreg));
               addInstr(env, AMD64Instr_SseMOVQ(idst, vgreg, False/*!toXMM*/));
               return idst;
            }
         }
         /* Otherwise we have to do it the longwinded way. */
         HReg ishift = iselIntExpr_R(env, arg2);
         HReg vshift = newVRegV(env);
         addInstr(env, AMD64Instr_SseMOVQ(ishift, vshift, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseReRg(op, vshift, vgreg));
         addInstr(env, AMD64Instr_SseMOVQ(idst, vgreg, False/*!toXMM*/));
         return idst;
      }

      if (e->Iex.Binop.op == Iop_Mul32x2) {
         const IRExpr* arg1 = e->Iex.Binop.arg1;
         const IRExpr* arg2 = e->Iex.Binop.arg2;
         vassert(typeOfIRExpr(env->type_env, arg1) == Ity_I64);
         vassert(typeOfIRExpr(env->type_env, arg2) == Ity_I64);
         HReg s1 = iselIntExpr_R(env, arg1);
         HReg s2 = iselIntExpr_R(env, arg2);
         HReg resLo = newVRegI(env);
         // resLo = (s1 *64 s2) & 0xFFFF'FFFF
         addInstr(env, mk_iMOVsd_RR(s1, resLo));
         addInstr(env, AMD64Instr_Alu64R(Aalu_MUL, AMD64RMI_Reg(s2), resLo));
         addInstr(env, AMD64Instr_MovxLQ(False, resLo, resLo));

         // resHi = ((s1 >>u 32) *64 (s2 >>u 32)) << 32;
         HReg resHi = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(s1, resHi));
         addInstr(env, AMD64Instr_Sh64(Ash_SHR, 32, resHi));
         HReg tmp = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(s2, tmp));
         addInstr(env, AMD64Instr_Sh64(Ash_SHR, 32, tmp));
         addInstr(env, AMD64Instr_Alu64R(Aalu_MUL, AMD64RMI_Reg(tmp), resHi));
         addInstr(env, AMD64Instr_Sh64(Ash_SHL, 32, resHi));

         // final result = resHi | resLo
         addInstr(env, AMD64Instr_Alu64R(Aalu_OR, AMD64RMI_Reg(resHi), resLo));
         return resLo;
      }

      // A few remaining SIMD64 ops require helper functions, at least for
      // now.
      Bool second_is_UInt = False;
      HWord fn = 0;
      switch (e->Iex.Binop.op) {
         case Iop_CatOddLanes16x4:
            fn = (HWord)h_generic_calc_CatOddLanes16x4; break;
         case Iop_CatEvenLanes16x4:
            fn = (HWord)h_generic_calc_CatEvenLanes16x4; break;
         case Iop_PermOrZero8x8:
            fn = (HWord)h_generic_calc_PermOrZero8x8; break;

         case Iop_QNarrowBin32Sto16Sx4:
            fn = (HWord)h_generic_calc_QNarrowBin32Sto16Sx4; break;
         case Iop_QNarrowBin16Sto8Sx8:
            fn = (HWord)h_generic_calc_QNarrowBin16Sto8Sx8; break;
         case Iop_QNarrowBin16Sto8Ux8:
            fn = (HWord)h_generic_calc_QNarrowBin16Sto8Ux8; break;

         case Iop_NarrowBin16to8x8:
            fn = (HWord)h_generic_calc_NarrowBin16to8x8; break;
         case Iop_NarrowBin32to16x4:
            fn = (HWord)h_generic_calc_NarrowBin32to16x4; break;

         case Iop_SarN8x8:
            fn = (HWord)h_generic_calc_SarN8x8;
            second_is_UInt = True;
            break;

         default:
            fn = (HWord)0; break;
      }
      if (fn != (HWord)0) {
         /* Note: the following assumes all helpers are of signature
               ULong fn ( ULong, ULong ), and they are
            not marked as regparm functions.
         */
         HReg dst  = newVRegI(env);
         HReg argL = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg argR = iselIntExpr_R(env, e->Iex.Binop.arg2);
         if (second_is_UInt)
            addInstr(env, AMD64Instr_MovxLQ(False, argR, argR));
         addInstr(env, mk_iMOVsd_RR(argL, hregAMD64_RDI()) );
         addInstr(env, mk_iMOVsd_RR(argR, hregAMD64_RSI()) );
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn, 2,
                                        mk_RetLoc_simple(RLPri_Int) ));
         addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(), dst));
         return dst;
      }

      // Half-float vector conversion
      if (e->Iex.Binop.op == Iop_F32toF16x4
          && (env->hwcaps & VEX_HWCAPS_AMD64_F16C)) {
         HReg srcV = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dstV = newVRegV(env);
         HReg dstI = newVRegI(env);
         set_SSE_rounding_mode( env, e->Iex.Binop.arg1 );
         addInstr(env, AMD64Instr_Sse32Fx4(Asse_F32toF16, srcV, dstV));
         set_SSE_rounding_default(env);
         addInstr(env, AMD64Instr_SseMOVQ(dstI, dstV, /*toXMM=*/False));
         return dstI;
      }

      break;
   }

   /* --------- UNARY OP --------- */
   case Iex_Unop: {

      /* 1Uto8(64to1(expr64)) */
      {
         DEFINE_PATTERN( p_1Uto8_64to1,
                         unop(Iop_1Uto8, unop(Iop_64to1, bind(0))) );
         if (matchIRExpr(&mi,p_1Uto8_64to1,e)) {
            const IRExpr* expr64 = mi.bindee[0];
            HReg    dst    = newVRegI(env);
            HReg    src    = iselIntExpr_R(env, expr64);
            addInstr(env, mk_iMOVsd_RR(src,dst) );
            addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                            AMD64RMI_Imm(1), dst));
            return dst;
         }
      }

      /* 8Uto64(LDle(expr64)) */
      {
         DEFINE_PATTERN(p_LDle8_then_8Uto64,
                        unop(Iop_8Uto64,
                             IRExpr_Load(Iend_LE,Ity_I8,bind(0))) );
         if (matchIRExpr(&mi,p_LDle8_then_8Uto64,e)) {
            HReg dst = newVRegI(env);
            AMD64AMode* amode = iselIntExpr_AMode ( env, mi.bindee[0] );
            addInstr(env, AMD64Instr_LoadEX(1,False,amode,dst));
            return dst;
         }
      }

      /* 16Uto64(LDle(expr64)) */
      {
         DEFINE_PATTERN(p_LDle16_then_16Uto64,
                        unop(Iop_16Uto64,
                             IRExpr_Load(Iend_LE,Ity_I16,bind(0))) );
         if (matchIRExpr(&mi,p_LDle16_then_16Uto64,e)) {
            HReg dst = newVRegI(env);
            AMD64AMode* amode = iselIntExpr_AMode ( env, mi.bindee[0] );
            addInstr(env, AMD64Instr_LoadEX(2,False,amode,dst));
            return dst;
         }
      }

      /* 32Uto64( Add32/Sub32/And32/Or32/Xor32(expr32, expr32) )
         Use 32 bit arithmetic and let the default zero-extend rule
         do the 32Uto64 for free. */
      if (e->Iex.Unop.op == Iop_32Uto64 && e->Iex.Unop.arg->tag == Iex_Binop) {
         IROp    opi  = e->Iex.Unop.arg->Iex.Binop.op; /* inner op */
         IRExpr* argL = e->Iex.Unop.arg->Iex.Binop.arg1;
         IRExpr* argR = e->Iex.Unop.arg->Iex.Binop.arg2;
         AMD64AluOp aluOp = Aalu_INVALID;
         switch (opi) {
            case Iop_Add32: aluOp = Aalu_ADD; break;
            case Iop_Sub32: aluOp = Aalu_SUB; break;
            case Iop_And32: aluOp = Aalu_AND; break;
            case Iop_Or32:  aluOp = Aalu_OR;  break;
            case Iop_Xor32: aluOp = Aalu_XOR; break;
            default: break;
         }
         if (aluOp != Aalu_INVALID) {
            /* For commutative ops we assume any literal values are on
               the second operand. */
            HReg dst      = newVRegI(env);
            HReg reg      = iselIntExpr_R(env, argL);
            AMD64RMI* rmi = iselIntExpr_RMI(env, argR);
            addInstr(env, mk_iMOVsd_RR(reg,dst));
            addInstr(env, AMD64Instr_Alu32R(aluOp, rmi, dst));
            return dst;
         }
         /* just fall through to normal handling for Iop_32Uto64 */
      }

      /* Fallback cases */
      switch (e->Iex.Unop.op) {
         case Iop_32Uto64:
         case Iop_32Sto64: {
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_MovxLQ(e->Iex.Unop.op == Iop_32Sto64,
                                            src, dst) );
            return dst;
         }
         case Iop_128HIto64: {
            HReg rHi, rLo;
            iselInt128Expr(&rHi,&rLo, env, e->Iex.Unop.arg);
            return rHi; /* and abandon rLo */
         }
         case Iop_128to64: {
            HReg rHi, rLo;
            iselInt128Expr(&rHi,&rLo, env, e->Iex.Unop.arg);
            return rLo; /* and abandon rHi */
         }
         case Iop_8Uto16:
         case Iop_8Uto32:
         case Iop_8Uto64:
         case Iop_16Uto64:
         case Iop_16Uto32: {
            HReg dst     = newVRegI(env);
            HReg src     = iselIntExpr_R(env, e->Iex.Unop.arg);
            Bool srcIs16 = toBool( e->Iex.Unop.op==Iop_16Uto32
                                   || e->Iex.Unop.op==Iop_16Uto64 );
            UInt mask    = srcIs16 ? 0xFFFF : 0xFF;
            addInstr(env, mk_iMOVsd_RR(src,dst) );
            addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                            AMD64RMI_Imm(mask), dst));
            return dst;
         }
         case Iop_8Sto16:
         case Iop_8Sto64:
         case Iop_8Sto32:
         case Iop_16Sto32:
         case Iop_16Sto64: {
            HReg dst     = newVRegI(env);
            HReg src     = iselIntExpr_R(env, e->Iex.Unop.arg);
            Bool srcIs16 = toBool( e->Iex.Unop.op==Iop_16Sto32
                                   || e->Iex.Unop.op==Iop_16Sto64 );
            UInt amt     = srcIs16 ? 48 : 56;
            addInstr(env, mk_iMOVsd_RR(src,dst) );
            addInstr(env, AMD64Instr_Sh64(Ash_SHL, amt, dst));
            addInstr(env, AMD64Instr_Sh64(Ash_SAR, amt, dst));
            return dst;
         }
         case Iop_Not8:
         case Iop_Not16:
         case Iop_Not32:
         case Iop_Not64: {
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, mk_iMOVsd_RR(src,dst) );
            addInstr(env, AMD64Instr_Unary64(Aun_NOT,dst));
            return dst;
         }
         case Iop_16HIto8:
         case Iop_32HIto16:
         case Iop_64HIto32: {
            HReg dst  = newVRegI(env);
            HReg src  = iselIntExpr_R(env, e->Iex.Unop.arg);
            Int shift = 0;
            switch (e->Iex.Unop.op) {
               case Iop_16HIto8:  shift = 8;  break;
               case Iop_32HIto16: shift = 16; break;
               case Iop_64HIto32: shift = 32; break;
               default: vassert(0);
            }
            addInstr(env, mk_iMOVsd_RR(src,dst) );
            addInstr(env, AMD64Instr_Sh64(Ash_SHR, shift, dst));
            return dst;
         }
         case Iop_1Uto64:
         case Iop_1Uto32:
         case Iop_1Uto8: {
            HReg dst           = newVRegI(env);
            AMD64CondCode cond = iselCondCode(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_Set64(cond,dst));
            return dst;
         }
         case Iop_1Sto8:
         case Iop_1Sto16:
         case Iop_1Sto32:
         case Iop_1Sto64: {
            /* could do better than this, but for now ... */
            HReg dst           = newVRegI(env);
            AMD64CondCode cond = iselCondCode(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_Set64(cond,dst));
            addInstr(env, AMD64Instr_Sh64(Ash_SHL, 63, dst));
            addInstr(env, AMD64Instr_Sh64(Ash_SAR, 63, dst));
            return dst;
         }
         case Iop_Ctz64: {
            /* Count trailing zeroes, implemented by amd64 'bsfq' */
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_Bsfr64(True,src,dst));
            return dst;
         }
         case Iop_Clz64: {
            /* Count leading zeroes.  Do 'bsrq' to establish the index
               of the highest set bit, and subtract that value from
               63. */
            HReg tmp = newVRegI(env);
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_Bsfr64(False,src,tmp));
            addInstr(env, AMD64Instr_Alu64R(Aalu_MOV, 
                                            AMD64RMI_Imm(63), dst));
            addInstr(env, AMD64Instr_Alu64R(Aalu_SUB,
                                            AMD64RMI_Reg(tmp), dst));
            return dst;
         }

         case Iop_CmpwNEZ64: {
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, mk_iMOVsd_RR(src,dst));
            addInstr(env, AMD64Instr_Unary64(Aun_NEG,dst));
            addInstr(env, AMD64Instr_Alu64R(Aalu_OR,
                                            AMD64RMI_Reg(src), dst));
            addInstr(env, AMD64Instr_Sh64(Ash_SAR, 63, dst));
            return dst;
         }

         case Iop_CmpwNEZ32: {
            HReg src = newVRegI(env);
            HReg dst = newVRegI(env);
            HReg pre = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, mk_iMOVsd_RR(pre,src));
            addInstr(env, AMD64Instr_MovxLQ(False, src, src));
            addInstr(env, mk_iMOVsd_RR(src,dst));
            addInstr(env, AMD64Instr_Unary64(Aun_NEG,dst));
            addInstr(env, AMD64Instr_Alu64R(Aalu_OR,
                                            AMD64RMI_Reg(src), dst));
            addInstr(env, AMD64Instr_Sh64(Ash_SAR, 63, dst));
            return dst;
         }

         case Iop_Left8:
         case Iop_Left16:
         case Iop_Left32:
         case Iop_Left64: {
            HReg dst = newVRegI(env);
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            addInstr(env, mk_iMOVsd_RR(src, dst));
            addInstr(env, AMD64Instr_Unary64(Aun_NEG, dst));
            addInstr(env, AMD64Instr_Alu64R(Aalu_OR, AMD64RMI_Reg(src), dst));
            return dst;
         }

         case Iop_V128to32: {
            HReg        dst     = newVRegI(env);
            HReg        vec     = iselVecExpr(env, e->Iex.Unop.arg);
            AMD64AMode* rsp_m16 = AMD64AMode_IR(-16, hregAMD64_RSP());
            addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vec, rsp_m16));
            addInstr(env, AMD64Instr_LoadEX(4, False/*z-widen*/, rsp_m16, dst));
            return dst;
         }

         /* V128{HI}to64 */
         case Iop_V128to64: {
            HReg dst = newVRegI(env);
            HReg vec = iselVecExpr(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_SseMOVQ(dst, vec, False/*!toXMM*/));
            return dst;
         }
         case Iop_V128HIto64: {
            HReg dst  = newVRegI(env);
            HReg vec  = iselVecExpr(env, e->Iex.Unop.arg);
            HReg vec2 = newVRegV(env);
            addInstr(env, mk_vMOVsd_RR(vec, vec2));
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 64, vec2));
            addInstr(env, AMD64Instr_SseMOVQ(dst, vec2, False/*!toXMM*/));
            return dst;
         }

         /* V256to64_{3,2,1,0} */
         case Iop_V256to64_0: case Iop_V256to64_1:
         case Iop_V256to64_2: case Iop_V256to64_3: {
            HReg vHi, vLo, vec;
            iselDVecExpr(&vHi, &vLo, env, e->Iex.Unop.arg);
            /* Do the first part of the selection by deciding which of
               the 128 bit registers to look at, and second part using
               the same scheme as for V128{HI}to64 above. */
            Bool low64of128 = True;
            switch (e->Iex.Unop.op) {
               case Iop_V256to64_0: vec = vLo; low64of128 = True;  break;
               case Iop_V256to64_1: vec = vLo; low64of128 = False; break;
               case Iop_V256to64_2: vec = vHi; low64of128 = True;  break;
               case Iop_V256to64_3: vec = vHi; low64of128 = False; break;
               default: vassert(0);
            }
            HReg dst = newVRegI(env);
            if (low64of128) {
               addInstr(env, AMD64Instr_SseMOVQ(dst, vec, False/*!toXMM*/));
            } else {
               HReg vec2 = newVRegV(env);
               addInstr(env, mk_vMOVsd_RR(vec, vec2));
               addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 64, vec2));
               addInstr(env, AMD64Instr_SseMOVQ(dst, vec2, False/*!toXMM*/));
            }
            return dst;
         }

         /* ReinterpF64asI64(e) */
         /* Given an IEEE754 double, produce an I64 with the same bit
            pattern. */
         case Iop_ReinterpF64asI64: {
            AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
            HReg        dst    = newVRegI(env);
            HReg        src    = iselDblExpr(env, e->Iex.Unop.arg);
            /* paranoia */
            set_SSE_rounding_default(env);
            addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, src, m8_rsp));
            addInstr(env, AMD64Instr_Alu64R(
                             Aalu_MOV, AMD64RMI_Mem(m8_rsp), dst));
            return dst;
         }

         /* ReinterpF32asI32(e) */
         /* Given an IEEE754 single, produce an I64 with the same bit
            pattern in the lower half. */
         case Iop_ReinterpF32asI32: {
            AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
            HReg        dst    = newVRegI(env);
            HReg        src    = iselFltExpr(env, e->Iex.Unop.arg);
            /* paranoia */
            set_SSE_rounding_default(env);
            addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 4, src, m8_rsp));
            addInstr(env, AMD64Instr_LoadEX(4, False/*unsigned*/, m8_rsp, dst ));
            return dst;
         }

         case Iop_16to8:
         case Iop_32to8:
         case Iop_64to8:
         case Iop_32to16:
         case Iop_64to16:
         case Iop_64to32:
            /* These are no-ops. */
            return iselIntExpr_R(env, e->Iex.Unop.arg);

         case Iop_GetMSBs8x8: {
            /* Note: the following assumes the helper is of
               signature
                  UInt fn ( ULong ), and is not a regparm fn.
            */
            HReg dst = newVRegI(env);
            HReg arg = iselIntExpr_R(env, e->Iex.Unop.arg);
            HWord fn = (HWord)h_generic_calc_GetMSBs8x8;
            addInstr(env, mk_iMOVsd_RR(arg, hregAMD64_RDI()) );
            addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn,
                                           1, mk_RetLoc_simple(RLPri_Int) ));
            /* MovxLQ is not exactly the right thing here.  We just
               need to get the bottom 8 bits of RAX into dst, and zero
               out everything else.  Assuming that the helper returns
               a UInt with the top 24 bits zeroed out, it'll do,
               though. */
            addInstr(env, AMD64Instr_MovxLQ(False, hregAMD64_RAX(), dst));
            return dst;
         }

         case Iop_GetMSBs8x16: {
            /* Note: the following assumes the helper is of signature
                  UInt fn ( ULong w64hi, ULong w64Lo ),
               and is not a regparm fn. */
            HReg dst = newVRegI(env);
            HReg vec = iselVecExpr(env, e->Iex.Unop.arg);
            HReg rsp = hregAMD64_RSP();
            HWord fn = (HWord)h_generic_calc_GetMSBs8x16;
            AMD64AMode* m8_rsp  = AMD64AMode_IR( -8, rsp);
            AMD64AMode* m16_rsp = AMD64AMode_IR(-16, rsp);
            addInstr(env, AMD64Instr_SseLdSt(False/*store*/,
                                             16, vec, m16_rsp));
            /* hi 64 bits into RDI -- the first arg */
            addInstr(env, AMD64Instr_Alu64R( Aalu_MOV, 
                                             AMD64RMI_Mem(m8_rsp),
                                             hregAMD64_RDI() )); /* 1st arg */
            /* lo 64 bits into RSI -- the 2nd arg */
            addInstr(env, AMD64Instr_Alu64R( Aalu_MOV, 
                                             AMD64RMI_Mem(m16_rsp),
                                             hregAMD64_RSI() )); /* 2nd arg */
            addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn,
                                           2, mk_RetLoc_simple(RLPri_Int) ));
            /* MovxLQ is not exactly the right thing here.  We just
               need to get the bottom 16 bits of RAX into dst, and zero
               out everything else.  Assuming that the helper returns
               a UInt with the top 16 bits zeroed out, it'll do,
               though. */
            addInstr(env, AMD64Instr_MovxLQ(False, hregAMD64_RAX(), dst));
            return dst;
         }

         default: 
            break;
      }

      /* Deal with unary 64-bit SIMD ops. */
      HWord fn = 0;
      switch (e->Iex.Unop.op) {
         case Iop_CmpNEZ32x2:
            fn = (HWord)h_generic_calc_CmpNEZ32x2; break;
         case Iop_CmpNEZ16x4:
            fn = (HWord)h_generic_calc_CmpNEZ16x4; break;
         case Iop_CmpNEZ8x8:
            fn = (HWord)h_generic_calc_CmpNEZ8x8; break;
         default:
            fn = (HWord)0; break;
      }
      if (fn != (HWord)0) {
         /* Note: the following assumes all helpers are of
            signature 
               ULong fn ( ULong ), and they are
            not marked as regparm functions. 
         */
         HReg dst = newVRegI(env);
         HReg arg = iselIntExpr_R(env, e->Iex.Unop.arg);
         addInstr(env, mk_iMOVsd_RR(arg, hregAMD64_RDI()) );
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn, 1,
                                        mk_RetLoc_simple(RLPri_Int) ));
         addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(), dst));
         return dst;
      }

      break;
   }

   /* --------- GET --------- */
   case Iex_Get: {
      if (ty == Ity_I64) {
         HReg dst = newVRegI(env);
         addInstr(env, AMD64Instr_Alu64R(
                          Aalu_MOV, 
                          AMD64RMI_Mem(
                             AMD64AMode_IR(e->Iex.Get.offset,
                                           hregAMD64_RBP())),
                          dst));
         return dst;
      }
      if (ty == Ity_I8 || ty == Ity_I16 || ty == Ity_I32) {
         HReg dst = newVRegI(env);
         addInstr(env, AMD64Instr_LoadEX(
                          toUChar(ty==Ity_I8 ? 1 : (ty==Ity_I16 ? 2 : 4)),
                          False,
                          AMD64AMode_IR(e->Iex.Get.offset,hregAMD64_RBP()),
                          dst));
         return dst;
      }
      break;
   }

   case Iex_GetI: {
      AMD64AMode* am 
         = genGuestArrayOffset(
              env, e->Iex.GetI.descr, 
                   e->Iex.GetI.ix, e->Iex.GetI.bias );
      HReg dst = newVRegI(env);
      if (ty == Ity_I8) {
         addInstr(env, AMD64Instr_LoadEX( 1, False, am, dst ));
         return dst;
      }
      if (ty == Ity_I64) {
         addInstr(env, AMD64Instr_Alu64R( Aalu_MOV, AMD64RMI_Mem(am), dst ));
         return dst;
      }
      break;
   }

   /* --------- CCALL --------- */
   case Iex_CCall: {
      HReg    dst = newVRegI(env);
      vassert(ty == e->Iex.CCall.retty);

      /* be very restrictive for now.  Only 64-bit ints allowed for
         args, and 64 or 32 bits for return type. */
      if (e->Iex.CCall.retty != Ity_I64 && e->Iex.CCall.retty != Ity_I32)
         goto irreducible;

      /* Marshal args, do the call. */
      UInt   addToSp = 0;
      RetLoc rloc    = mk_RetLoc_INVALID();
      doHelperCall( &addToSp, &rloc, env, NULL/*guard*/,
                    e->Iex.CCall.cee, e->Iex.CCall.retty, e->Iex.CCall.args );
      vassert(is_sane_RetLoc(rloc));
      vassert(rloc.pri == RLPri_Int);
      vassert(addToSp == 0);

      /* Move to dst, and zero out the top 32 bits if the result type is
         Ity_I32.  Probably overkill, but still .. */
      if (e->Iex.CCall.retty == Ity_I64)
         addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(), dst));
      else
         addInstr(env, AMD64Instr_MovxLQ(False, hregAMD64_RAX(), dst));

      return dst;
   }

   /* --------- LITERAL --------- */
   /* 64/32/16/8-bit literals */
   case Iex_Const:
      if (ty == Ity_I64) {
         HReg r = newVRegI(env);
         addInstr(env, AMD64Instr_Imm64(e->Iex.Const.con->Ico.U64, r));
         return r;
      } else {
         AMD64RMI* rmi = iselIntExpr_RMI ( env, e );
         HReg      r   = newVRegI(env);
         addInstr(env, AMD64Instr_Alu64R(Aalu_MOV, rmi, r));
         return r;
      }

   /* --------- MULTIPLEX --------- */
   case Iex_ITE: { // VFD
      if ((ty == Ity_I64 || ty == Ity_I32 || ty == Ity_I16 || ty == Ity_I8)
          && typeOfIRExpr(env->type_env,e->Iex.ITE.cond) == Ity_I1) {
         HReg     r1  = iselIntExpr_R(env, e->Iex.ITE.iftrue);
         HReg     r0  = iselIntExpr_R(env, e->Iex.ITE.iffalse);
         HReg     dst = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(r1,dst));
         AMD64CondCode cc = iselCondCode(env, e->Iex.ITE.cond);
         addInstr(env, AMD64Instr_CMov64(cc ^ 1, r0, dst));
         return dst;
      }
      break;
   }

   /* --------- TERNARY OP --------- */
   case Iex_Triop: {
      IRTriop *triop = e->Iex.Triop.details;
      /* C3210 flags following FPU partial remainder (fprem), both
         IEEE compliant (PREM1) and non-IEEE compliant (PREM). */
      if (triop->op == Iop_PRemC3210F64
          || triop->op == Iop_PRem1C3210F64) {
         AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
         HReg        arg1   = iselDblExpr(env, triop->arg2);
         HReg        arg2   = iselDblExpr(env, triop->arg3);
         HReg        dst    = newVRegI(env);
         addInstr(env, AMD64Instr_A87Free(2));

         /* one arg -> top of x87 stack */
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, arg2, m8_rsp));
         addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));

         /* other arg -> top of x87 stack */
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, arg1, m8_rsp));
         addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));

         switch (triop->op) {
            case Iop_PRemC3210F64:
               addInstr(env, AMD64Instr_A87FpOp(Afp_PREM));
               break;
            case Iop_PRem1C3210F64:
               addInstr(env, AMD64Instr_A87FpOp(Afp_PREM1));
               break;
            default: 
               vassert(0);
         }
         /* Ignore the result, and instead make off with the FPU's
            C3210 flags (in the status word). */
         addInstr(env, AMD64Instr_A87StSW(m8_rsp));
         addInstr(env, AMD64Instr_Alu64R(Aalu_MOV,AMD64RMI_Mem(m8_rsp),dst));
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,AMD64RMI_Imm(0x4700),dst));
         return dst;
      }
      break;
   }

   default: 
   break;
   } /* switch (e->tag) */

   /* We get here if no pattern matched. */
  irreducible:
   ppIRExpr(e);
   vpanic("iselIntExpr_R(amd64): cannot reduce tree");
}


/*---------------------------------------------------------*/
/*--- ISEL: Integer expression auxiliaries              ---*/
/*---------------------------------------------------------*/

/* --------------------- AMODEs --------------------- */

/* Return an AMode which computes the value of the specified
   expression, possibly also adding insns to the code list as a
   result.  The expression may only be a 32-bit one.
*/

static AMD64AMode* iselIntExpr_AMode ( ISelEnv* env, const IRExpr* e )
{
   AMD64AMode* am = iselIntExpr_AMode_wrk(env, e);
   vassert(sane_AMode(am));
   return am;
}

/* DO NOT CALL THIS DIRECTLY ! */
static AMD64AMode* iselIntExpr_AMode_wrk ( ISelEnv* env, const IRExpr* e )
{
   MatchInfo mi;
   DECLARE_PATTERN(p_complex);
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(ty == Ity_I64);

   /* Add64( Add64(expr1, Shl64(expr2, imm8)), simm32 ) */
   /*              bind0        bind1  bind2   bind3   */
   DEFINE_PATTERN(p_complex,
      binop( Iop_Add64,
             binop( Iop_Add64, 
                    bind(0), 
                    binop(Iop_Shl64, bind(1), bind(2))
                  ),
             bind(3)
           )
   );
   if (matchIRExpr(&mi, p_complex, e)) {
      const IRExpr* expr1  = mi.bindee[0];
      const IRExpr* expr2  = mi.bindee[1];
      const IRExpr* imm8   = mi.bindee[2];
      const IRExpr* simm32 = mi.bindee[3];
      if (imm8->tag == Iex_Const 
          && imm8->Iex.Const.con->tag == Ico_U8
          && imm8->Iex.Const.con->Ico.U8 < 4
          /* imm8 is OK, now check simm32 */
          && simm32->tag == Iex_Const
          && simm32->Iex.Const.con->tag == Ico_U64
          && fitsIn32Bits(simm32->Iex.Const.con->Ico.U64)) {
         UInt shift = imm8->Iex.Const.con->Ico.U8;
         UInt offset = toUInt(simm32->Iex.Const.con->Ico.U64);
         HReg r1 = iselIntExpr_R(env, expr1);
         HReg r2 = iselIntExpr_R(env, expr2);
         vassert(shift == 0 || shift == 1 || shift == 2 || shift == 3);
         return AMD64AMode_IRRS(offset, r1, r2, shift);
      }
   }

   /* Add64(expr1, Shl64(expr2, imm)) */
   if (e->tag == Iex_Binop
       && e->Iex.Binop.op == Iop_Add64
       && e->Iex.Binop.arg2->tag == Iex_Binop
       && e->Iex.Binop.arg2->Iex.Binop.op == Iop_Shl64
       && e->Iex.Binop.arg2->Iex.Binop.arg2->tag == Iex_Const
       && e->Iex.Binop.arg2->Iex.Binop.arg2->Iex.Const.con->tag == Ico_U8) {
      UInt shift = e->Iex.Binop.arg2->Iex.Binop.arg2->Iex.Const.con->Ico.U8;
      if (shift == 1 || shift == 2 || shift == 3) {
         HReg r1 = iselIntExpr_R(env, e->Iex.Binop.arg1);
         HReg r2 = iselIntExpr_R(env, e->Iex.Binop.arg2->Iex.Binop.arg1 );
         return AMD64AMode_IRRS(0, r1, r2, shift);
      }
   }

   /* Add64(expr,i) */
   if (e->tag == Iex_Binop 
       && e->Iex.Binop.op == Iop_Add64
       && e->Iex.Binop.arg2->tag == Iex_Const
       && e->Iex.Binop.arg2->Iex.Const.con->tag == Ico_U64
       && fitsIn32Bits(e->Iex.Binop.arg2->Iex.Const.con->Ico.U64)) {
      HReg r1 = iselIntExpr_R(env, e->Iex.Binop.arg1);
      return AMD64AMode_IR(
                toUInt(e->Iex.Binop.arg2->Iex.Const.con->Ico.U64), 
                r1
             );
   }

   /* Doesn't match anything in particular.  Generate it into
      a register and use that. */
   {
      HReg r1 = iselIntExpr_R(env, e);
      return AMD64AMode_IR(0, r1);
   }
}


/* --------------------- RMIs --------------------- */

/* Similarly, calculate an expression into an X86RMI operand.  As with
   iselIntExpr_R, the expression can have type 32, 16 or 8 bits.  */

static AMD64RMI* iselIntExpr_RMI ( ISelEnv* env, const IRExpr* e )
{
   AMD64RMI* rmi = iselIntExpr_RMI_wrk(env, e);
   /* sanity checks ... */
   switch (rmi->tag) {
      case Armi_Imm:
         return rmi;
      case Armi_Reg:
         vassert(hregClass(rmi->Armi.Reg.reg) == HRcInt64);
         vassert(hregIsVirtual(rmi->Armi.Reg.reg));
         return rmi;
      case Armi_Mem:
         vassert(sane_AMode(rmi->Armi.Mem.am));
         return rmi;
      default:
         vpanic("iselIntExpr_RMI: unknown amd64 RMI tag");
   }
}

/* DO NOT CALL THIS DIRECTLY ! */
static AMD64RMI* iselIntExpr_RMI_wrk ( ISelEnv* env, const IRExpr* e )
{
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(ty == Ity_I64 || ty == Ity_I32 
           || ty == Ity_I16 || ty == Ity_I8);

   /* special case: immediate 64/32/16/8 */
   if (e->tag == Iex_Const) {
      switch (e->Iex.Const.con->tag) {
        case Ico_U64:
           if (fitsIn32Bits(e->Iex.Const.con->Ico.U64)) {
              return AMD64RMI_Imm(toUInt(e->Iex.Const.con->Ico.U64));
           }
           break;
         case Ico_U32:
            return AMD64RMI_Imm(e->Iex.Const.con->Ico.U32); break;
         case Ico_U16:
            return AMD64RMI_Imm(0xFFFF & e->Iex.Const.con->Ico.U16); break;
         case Ico_U8:
            return AMD64RMI_Imm(0xFF & e->Iex.Const.con->Ico.U8); break;
         default:
            vpanic("iselIntExpr_RMI.Iex_Const(amd64)");
      }
   }

   /* special case: 64-bit GET */
   if (e->tag == Iex_Get && ty == Ity_I64) {
      return AMD64RMI_Mem(AMD64AMode_IR(e->Iex.Get.offset,
                                        hregAMD64_RBP()));
   }

   /* special case: 64-bit load from memory */
   if (e->tag == Iex_Load && ty == Ity_I64
       && e->Iex.Load.end == Iend_LE) {
      AMD64AMode* am = iselIntExpr_AMode(env, e->Iex.Load.addr);
      return AMD64RMI_Mem(am);
   }

   /* default case: calculate into a register and return that */
   {
      HReg r = iselIntExpr_R ( env, e );
      return AMD64RMI_Reg(r);
   }
}


/* --------------------- RIs --------------------- */

/* Calculate an expression into an AMD64RI operand.  As with
   iselIntExpr_R, the expression can have type 64, 32, 16 or 8
   bits. */

static AMD64RI* iselIntExpr_RI ( ISelEnv* env, const IRExpr* e )
{
   AMD64RI* ri = iselIntExpr_RI_wrk(env, e);
   /* sanity checks ... */
   switch (ri->tag) {
      case Ari_Imm:
         return ri;
      case Ari_Reg:
         vassert(hregClass(ri->Ari.Reg.reg) == HRcInt64);
         vassert(hregIsVirtual(ri->Ari.Reg.reg));
         return ri;
      default:
         vpanic("iselIntExpr_RI: unknown amd64 RI tag");
   }
}

/* DO NOT CALL THIS DIRECTLY ! */
static AMD64RI* iselIntExpr_RI_wrk ( ISelEnv* env, const IRExpr* e )
{
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(ty == Ity_I64 || ty == Ity_I32 
           || ty == Ity_I16 || ty == Ity_I8);

   /* special case: immediate */
   if (e->tag == Iex_Const) {
      switch (e->Iex.Const.con->tag) {
        case Ico_U64:
           if (fitsIn32Bits(e->Iex.Const.con->Ico.U64)) {
              return AMD64RI_Imm(toUInt(e->Iex.Const.con->Ico.U64));
           }
           break;
         case Ico_U32:
            return AMD64RI_Imm(e->Iex.Const.con->Ico.U32);
         case Ico_U16: 
            return AMD64RI_Imm(0xFFFF & e->Iex.Const.con->Ico.U16);
         case Ico_U8:
            return AMD64RI_Imm(0xFF & e->Iex.Const.con->Ico.U8);
         default:
            vpanic("iselIntExpr_RMI.Iex_Const(amd64)");
      }
   }

   /* default case: calculate into a register and return that */
   {
      HReg r = iselIntExpr_R ( env, e );
      return AMD64RI_Reg(r);
   }
}


/* --------------------- RMs --------------------- */

/* Similarly, calculate an expression into an AMD64RM operand.  As
   with iselIntExpr_R, the expression can have type 64, 32, 16 or 8
   bits.  */

static AMD64RM* iselIntExpr_RM ( ISelEnv* env, const IRExpr* e )
{
   AMD64RM* rm = iselIntExpr_RM_wrk(env, e);
   /* sanity checks ... */
   switch (rm->tag) {
      case Arm_Reg:
         vassert(hregClass(rm->Arm.Reg.reg) == HRcInt64);
         vassert(hregIsVirtual(rm->Arm.Reg.reg));
         return rm;
      case Arm_Mem:
         vassert(sane_AMode(rm->Arm.Mem.am));
         return rm;
      default:
         vpanic("iselIntExpr_RM: unknown amd64 RM tag");
   }
}

/* DO NOT CALL THIS DIRECTLY ! */
static AMD64RM* iselIntExpr_RM_wrk ( ISelEnv* env, const IRExpr* e )
{
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(ty == Ity_I64 || ty == Ity_I32 || ty == Ity_I16 || ty == Ity_I8);

   /* special case: 64-bit GET */
   if (e->tag == Iex_Get && ty == Ity_I64) {
      return AMD64RM_Mem(AMD64AMode_IR(e->Iex.Get.offset,
                                       hregAMD64_RBP()));
   }

   /* special case: load from memory */

   /* default case: calculate into a register and return that */
   {
      HReg r = iselIntExpr_R ( env, e );
      return AMD64RM_Reg(r);
   }
}


/* --------------------- CONDCODE --------------------- */

/* Generate code to evaluated a bit-typed expression, returning the
   condition code which would correspond when the expression would
   notionally have returned 1. */

static AMD64CondCode iselCondCode ( ISelEnv* env, const IRExpr* e )
{
   /* Uh, there's nothing we can sanity check here, unfortunately. */
   return iselCondCode_wrk(env,e);
}

/* DO NOT CALL THIS DIRECTLY ! */
static AMD64CondCode iselCondCode_wrk ( ISelEnv* env, const IRExpr* e )
{
   vassert(e);
   vassert(typeOfIRExpr(env->type_env,e) == Ity_I1);

   /* var */
   if (e->tag == Iex_RdTmp) {
      HReg r64 = lookupIRTemp(env, e->Iex.RdTmp.tmp);
      addInstr(env, AMD64Instr_Test64(1,r64));
      return Acc_NZ;
   }

   /* Constant 1:Bit */
   if (e->tag == Iex_Const) {
      HReg r;
      vassert(e->Iex.Const.con->tag == Ico_U1);
      vassert(e->Iex.Const.con->Ico.U1 == True 
              || e->Iex.Const.con->Ico.U1 == False);
      r = newVRegI(env);
      addInstr(env, AMD64Instr_Alu64R(Aalu_MOV,AMD64RMI_Imm(0),r));
      addInstr(env, AMD64Instr_Alu64R(Aalu_XOR,AMD64RMI_Reg(r),r));
      return e->Iex.Const.con->Ico.U1 ? Acc_Z : Acc_NZ;
   }

   /* Not1(...) */
   if (e->tag == Iex_Unop && e->Iex.Unop.op == Iop_Not1) {
      /* Generate code for the arg, and negate the test condition */
      return 1 ^ iselCondCode(env, e->Iex.Unop.arg);
   }

   /* --- patterns rooted at: 64to1 --- */

   /* 64to1 */
   if (e->tag == Iex_Unop && e->Iex.Unop.op == Iop_64to1) {
      HReg reg = iselIntExpr_R(env, e->Iex.Unop.arg);
      addInstr(env, AMD64Instr_Test64(1,reg));
      return Acc_NZ;
   }

   /* --- patterns rooted at: 32to1 --- */

   /* 32to1 */
   if (e->tag == Iex_Unop && e->Iex.Unop.op == Iop_32to1) {
      HReg reg = iselIntExpr_R(env, e->Iex.Unop.arg);
      addInstr(env, AMD64Instr_Test64(1,reg));
      return Acc_NZ;
   }

   /* --- patterns rooted at: CmpNEZ8 --- */

   /* CmpNEZ8(x) */
   if (e->tag == Iex_Unop 
       && e->Iex.Unop.op == Iop_CmpNEZ8) {
      HReg r = iselIntExpr_R(env, e->Iex.Unop.arg);
      addInstr(env, AMD64Instr_Test64(0xFF,r));
      return Acc_NZ;
   }

   /* --- patterns rooted at: CmpNEZ16 --- */

   /* CmpNEZ16(x) */
   if (e->tag == Iex_Unop 
       && e->Iex.Unop.op == Iop_CmpNEZ16) {
      HReg r = iselIntExpr_R(env, e->Iex.Unop.arg);
      addInstr(env, AMD64Instr_Test64(0xFFFF,r));
      return Acc_NZ;
   }

   /* --- patterns rooted at: CmpNEZ32 --- */

   if (e->tag == Iex_Unop
       && e->Iex.Unop.op == Iop_CmpNEZ32) {
      IRExpr* arg = e->Iex.Unop.arg;
      if (arg->tag == Iex_Binop
          && (arg->Iex.Binop.op == Iop_Or32
              || arg->Iex.Binop.op == Iop_And32)) {
         /* CmpNEZ32(Or32(x,y)) */
         /* CmpNEZ32(And32(x,y)) */
         HReg      r0   = iselIntExpr_R(env, arg->Iex.Binop.arg1);
         AMD64RMI* rmi1 = iselIntExpr_RMI(env, arg->Iex.Binop.arg2);
         HReg      tmp  = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(r0, tmp));
         addInstr(env, AMD64Instr_Alu32R(
                          arg->Iex.Binop.op == Iop_Or32 ? Aalu_OR : Aalu_AND,
                          rmi1, tmp));
         return Acc_NZ;
      }
      /* CmpNEZ32(x) */
      HReg      r1   = iselIntExpr_R(env, arg);
      AMD64RMI* rmi2 = AMD64RMI_Imm(0);
      addInstr(env, AMD64Instr_Alu32R(Aalu_CMP,rmi2,r1));
      return Acc_NZ;
   }

   /* --- patterns rooted at: CmpNEZ64 --- */

   if (e->tag == Iex_Unop
       && e->Iex.Unop.op == Iop_CmpNEZ64) {
      IRExpr* arg = e->Iex.Unop.arg;
      if (arg->tag == Iex_Binop
          && (arg->Iex.Binop.op == Iop_Or64
              || arg->Iex.Binop.op == Iop_And64)) {
         /* CmpNEZ64(Or64(x,y)) */
         /* CmpNEZ64(And64(x,y)) */
         HReg      r0   = iselIntExpr_R(env, arg->Iex.Binop.arg1);
         AMD64RMI* rmi1 = iselIntExpr_RMI(env, arg->Iex.Binop.arg2);
         HReg      tmp  = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(r0, tmp));
         addInstr(env, AMD64Instr_Alu64R(
                          arg->Iex.Binop.op == Iop_Or64 ? Aalu_OR : Aalu_AND,
                          rmi1, tmp));
         return Acc_NZ;
      }
      /* CmpNEZ64(x) */
      HReg      r1   = iselIntExpr_R(env, arg);
      AMD64RMI* rmi2 = AMD64RMI_Imm(0);
      addInstr(env, AMD64Instr_Alu64R(Aalu_CMP,rmi2,r1));
      return Acc_NZ;
   }

   /* --- patterns rooted at: Cmp{EQ,NE}{8,16,32} --- */

   /* CmpEQ8 / CmpNE8 */
   if (e->tag == Iex_Binop 
       && (e->Iex.Binop.op == Iop_CmpEQ8
           || e->Iex.Binop.op == Iop_CmpNE8
           || e->Iex.Binop.op == Iop_CasCmpEQ8
           || e->Iex.Binop.op == Iop_CasCmpNE8)) {
      if (isZeroU8(e->Iex.Binop.arg2)) {
         HReg      r1   = iselIntExpr_R(env, e->Iex.Binop.arg1);
         addInstr(env, AMD64Instr_Test64(0xFF,r1));
         switch (e->Iex.Binop.op) {
            case Iop_CmpEQ8: case Iop_CasCmpEQ8: return Acc_Z;
            case Iop_CmpNE8: case Iop_CasCmpNE8: return Acc_NZ;
            default: vpanic("iselCondCode(amd64): CmpXX8(expr,0:I8)");
         }
      } else {
         HReg      r1   = iselIntExpr_R(env, e->Iex.Binop.arg1);
         AMD64RMI* rmi2 = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
         HReg      r    = newVRegI(env);
         addInstr(env, mk_iMOVsd_RR(r1,r));
         addInstr(env, AMD64Instr_Alu64R(Aalu_XOR,rmi2,r));
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,AMD64RMI_Imm(0xFF),r));
         switch (e->Iex.Binop.op) {
            case Iop_CmpEQ8: case Iop_CasCmpEQ8: return Acc_Z;
            case Iop_CmpNE8: case Iop_CasCmpNE8: return Acc_NZ;
            default: vpanic("iselCondCode(amd64): CmpXX8(expr,expr)");
         }
      }
   }

   /* CmpEQ16 / CmpNE16 */
   if (e->tag == Iex_Binop 
       && (e->Iex.Binop.op == Iop_CmpEQ16
           || e->Iex.Binop.op == Iop_CmpNE16
           || e->Iex.Binop.op == Iop_CasCmpEQ16
           || e->Iex.Binop.op == Iop_CasCmpNE16)) {
      HReg      r1   = iselIntExpr_R(env, e->Iex.Binop.arg1);
      AMD64RMI* rmi2 = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
      HReg      r    = newVRegI(env);
      addInstr(env, mk_iMOVsd_RR(r1,r));
      addInstr(env, AMD64Instr_Alu64R(Aalu_XOR,rmi2,r));
      addInstr(env, AMD64Instr_Alu64R(Aalu_AND,AMD64RMI_Imm(0xFFFF),r));
      switch (e->Iex.Binop.op) {
         case Iop_CmpEQ16: case Iop_CasCmpEQ16: return Acc_Z;
         case Iop_CmpNE16: case Iop_CasCmpNE16: return Acc_NZ;
         default: vpanic("iselCondCode(amd64): CmpXX16");
      }
   }

   /* CmpNE64(ccall, 64-bit constant) (--smc-check=all optimisation).
      Saves a "movq %rax, %tmp" compared to the default route. */
   if (e->tag == Iex_Binop 
       && e->Iex.Binop.op == Iop_CmpNE64
       && e->Iex.Binop.arg1->tag == Iex_CCall
       && e->Iex.Binop.arg2->tag == Iex_Const) {
      IRExpr* cal = e->Iex.Binop.arg1;
      IRExpr* con = e->Iex.Binop.arg2;
      HReg    tmp = newVRegI(env);
      /* clone & partial-eval of generic Iex_CCall and Iex_Const cases */
      vassert(cal->Iex.CCall.retty == Ity_I64); /* else ill-typed IR */
      vassert(con->Iex.Const.con->tag == Ico_U64);
      /* Marshal args, do the call. */
      UInt   addToSp = 0;
      RetLoc rloc    = mk_RetLoc_INVALID();
      doHelperCall( &addToSp, &rloc, env, NULL/*guard*/,
                    cal->Iex.CCall.cee,
                    cal->Iex.CCall.retty, cal->Iex.CCall.args );
      vassert(is_sane_RetLoc(rloc));
      vassert(rloc.pri == RLPri_Int);
      vassert(addToSp == 0);
      /* */
      addInstr(env, AMD64Instr_Imm64(con->Iex.Const.con->Ico.U64, tmp));
      addInstr(env, AMD64Instr_Alu64R(Aalu_CMP,
                                      AMD64RMI_Reg(hregAMD64_RAX()), tmp));
      return Acc_NZ;
   }

   /* Cmp*64*(x,y) */
   if (e->tag == Iex_Binop 
       && (e->Iex.Binop.op == Iop_CmpEQ64
           || e->Iex.Binop.op == Iop_CmpNE64
           || e->Iex.Binop.op == Iop_CmpLT64S
           || e->Iex.Binop.op == Iop_CmpLT64U
           || e->Iex.Binop.op == Iop_CmpLE64S
           || e->Iex.Binop.op == Iop_CmpLE64U
           || e->Iex.Binop.op == Iop_CasCmpEQ64
           || e->Iex.Binop.op == Iop_CasCmpNE64
           || e->Iex.Binop.op == Iop_ExpCmpNE64)) {
      HReg      r1   = iselIntExpr_R(env, e->Iex.Binop.arg1);
      AMD64RMI* rmi2 = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
      addInstr(env, AMD64Instr_Alu64R(Aalu_CMP,rmi2,r1));
      switch (e->Iex.Binop.op) {
         case Iop_CmpEQ64: case Iop_CasCmpEQ64: return Acc_Z;
         case Iop_CmpNE64:
         case Iop_CasCmpNE64: case Iop_ExpCmpNE64: return Acc_NZ;
         case Iop_CmpLT64S: return Acc_L;
         case Iop_CmpLT64U: return Acc_B;
         case Iop_CmpLE64S: return Acc_LE;
         case Iop_CmpLE64U: return Acc_BE;
         default: vpanic("iselCondCode(amd64): CmpXX64");
      }
   }

   /* Cmp*32*(x,y) */
   if (e->tag == Iex_Binop 
       && (e->Iex.Binop.op == Iop_CmpEQ32
           || e->Iex.Binop.op == Iop_CmpNE32
           || e->Iex.Binop.op == Iop_CmpLT32S
           || e->Iex.Binop.op == Iop_CmpLT32U
           || e->Iex.Binop.op == Iop_CmpLE32S
           || e->Iex.Binop.op == Iop_CmpLE32U
           || e->Iex.Binop.op == Iop_CasCmpEQ32
           || e->Iex.Binop.op == Iop_CasCmpNE32
           || e->Iex.Binop.op == Iop_ExpCmpNE32)) {
      HReg      r1   = iselIntExpr_R(env, e->Iex.Binop.arg1);
      AMD64RMI* rmi2 = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
      addInstr(env, AMD64Instr_Alu32R(Aalu_CMP,rmi2,r1));
      switch (e->Iex.Binop.op) {
         case Iop_CmpEQ32: case Iop_CasCmpEQ32: return Acc_Z;
         case Iop_CmpNE32:
         case Iop_CasCmpNE32: case Iop_ExpCmpNE32: return Acc_NZ;
         case Iop_CmpLT32S: return Acc_L;
         case Iop_CmpLT32U: return Acc_B;
         case Iop_CmpLE32S: return Acc_LE;
         case Iop_CmpLE32U: return Acc_BE;
         default: vpanic("iselCondCode(amd64): CmpXX32");
      }
   }

   /* And1(x,y), Or1(x,y) */
   /* FIXME: We could (and probably should) do a lot better here.  If both args
      are in temps already then we can just emit a reg-reg And/Or directly,
      followed by the final Test. */
   if (e->tag == Iex_Binop
       && (e->Iex.Binop.op == Iop_And1 || e->Iex.Binop.op == Iop_Or1)) {
      // We could probably be cleverer about this.  In the meantime ..
      HReg x_as_64 = newVRegI(env);
      AMD64CondCode cc_x = iselCondCode(env, e->Iex.Binop.arg1);
      addInstr(env, AMD64Instr_Set64(cc_x, x_as_64));
      HReg y_as_64 = newVRegI(env);
      AMD64CondCode cc_y = iselCondCode(env, e->Iex.Binop.arg2);
      addInstr(env, AMD64Instr_Set64(cc_y, y_as_64));
      AMD64AluOp aop = e->Iex.Binop.op == Iop_And1 ? Aalu_AND : Aalu_OR;
      addInstr(env, AMD64Instr_Alu64R(aop, AMD64RMI_Reg(x_as_64), y_as_64));
      addInstr(env, AMD64Instr_Test64(1, y_as_64));
      return Acc_NZ;
   }

   ppIRExpr(e);
   vpanic("iselCondCode(amd64)");
}


/*---------------------------------------------------------*/
/*--- ISEL: Integer expressions (128 bit)               ---*/
/*---------------------------------------------------------*/

/* Compute a 128-bit value into a register pair, which is returned as
   the first two parameters.  As with iselIntExpr_R, these may be
   either real or virtual regs; in any case they must not be changed
   by subsequent code emitted by the caller.  */

static void iselInt128Expr ( HReg* rHi, HReg* rLo, 
                             ISelEnv* env, const IRExpr* e )
{
   iselInt128Expr_wrk(rHi, rLo, env, e);
#  if 0
   vex_printf("\n"); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(*rHi) == HRcInt64);
   vassert(hregIsVirtual(*rHi));
   vassert(hregClass(*rLo) == HRcInt64);
   vassert(hregIsVirtual(*rLo));
}

/* DO NOT CALL THIS DIRECTLY ! */
static void iselInt128Expr_wrk ( HReg* rHi, HReg* rLo, 
                                 ISelEnv* env, const IRExpr* e )
{
   vassert(e);
   vassert(typeOfIRExpr(env->type_env,e) == Ity_I128);

   /* read 128-bit IRTemp */
   if (e->tag == Iex_RdTmp) {
      lookupIRTempPair( rHi, rLo, env, e->Iex.RdTmp.tmp);
      return;
   }
 
   /* --------- BINARY ops --------- */
   if (e->tag == Iex_Binop) {
      switch (e->Iex.Binop.op) {
         /* 64 x 64 -> 128 multiply */
         case Iop_MullU64:
         case Iop_MullS64: {
            /* get one operand into %rax, and the other into a R/M.
               Need to make an educated guess about which is better in
               which. */
            HReg     tLo    = newVRegI(env);
            HReg     tHi    = newVRegI(env);
            Bool     syned  = toBool(e->Iex.Binop.op == Iop_MullS64);
            AMD64RM* rmLeft = iselIntExpr_RM(env, e->Iex.Binop.arg1);
            HReg     rRight = iselIntExpr_R(env, e->Iex.Binop.arg2);
            addInstr(env, mk_iMOVsd_RR(rRight, hregAMD64_RAX()));
            addInstr(env, AMD64Instr_MulL(syned, rmLeft));
            /* Result is now in RDX:RAX.  Tell the caller. */
            addInstr(env, mk_iMOVsd_RR(hregAMD64_RDX(), tHi));
            addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(), tLo));
            *rHi = tHi;
            *rLo = tLo;
            return;
         }

         /* 128 x 64 -> (64(rem),64(div)) division */
         case Iop_DivModU128to64:
         case Iop_DivModS128to64: {
            /* Get the 128-bit operand into rdx:rax, and the other into
               any old R/M. */
            HReg sHi, sLo;
            HReg     tLo     = newVRegI(env);
            HReg     tHi     = newVRegI(env);
            Bool     syned   = toBool(e->Iex.Binop.op == Iop_DivModS128to64);
            AMD64RM* rmRight = iselIntExpr_RM(env, e->Iex.Binop.arg2);
            iselInt128Expr(&sHi,&sLo, env, e->Iex.Binop.arg1);
            addInstr(env, mk_iMOVsd_RR(sHi, hregAMD64_RDX()));
            addInstr(env, mk_iMOVsd_RR(sLo, hregAMD64_RAX()));
            addInstr(env, AMD64Instr_Div(syned, 8, rmRight));
            addInstr(env, mk_iMOVsd_RR(hregAMD64_RDX(), tHi));
            addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(), tLo));
            *rHi = tHi;
            *rLo = tLo;
            return;
         }

         /* 64HLto128(e1,e2) */
         case Iop_64HLto128:
            *rHi = iselIntExpr_R(env, e->Iex.Binop.arg1);
            *rLo = iselIntExpr_R(env, e->Iex.Binop.arg2);
            return;

         default: 
            break;
      }
   } /* if (e->tag == Iex_Binop) */

   ppIRExpr(e);
   vpanic("iselInt128Expr");
}


/*---------------------------------------------------------*/
/*--- ISEL: Floating point expressions (32 bit)         ---*/
/*---------------------------------------------------------*/

/* Nothing interesting here; really just wrappers for
   64-bit stuff. */

static HReg iselFltExpr ( ISelEnv* env, const IRExpr* e )
{
   HReg r = iselFltExpr_wrk( env, e );
#  if 0
   vex_printf("\n"); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(r) == HRcVec128);
   vassert(hregIsVirtual(r));
   return r;
}

/* DO NOT CALL THIS DIRECTLY */
static HReg iselFltExpr_wrk ( ISelEnv* env, const IRExpr* e )
{
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(ty == Ity_F32);

   if (e->tag == Iex_RdTmp) {
      return lookupIRTemp(env, e->Iex.RdTmp.tmp);
   }

   if (e->tag == Iex_Load && e->Iex.Load.end == Iend_LE) {
      AMD64AMode* am;
      HReg res = newVRegV(env);
      vassert(e->Iex.Load.ty == Ity_F32);
      am = iselIntExpr_AMode(env, e->Iex.Load.addr);
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 4, res, am));
      return res;
   }

   if (e->tag == Iex_Binop
       && e->Iex.Binop.op == Iop_F64toF32) {
      /* Although the result is still held in a standard SSE register,
         we need to round it to reflect the loss of accuracy/range
         entailed in casting it to a 32-bit float. */
      HReg dst = newVRegV(env);
      HReg src = iselDblExpr(env, e->Iex.Binop.arg2);
      set_SSE_rounding_mode( env, e->Iex.Binop.arg1 );
      addInstr(env, AMD64Instr_SseSDSS(True/*D->S*/,src,dst));
      set_SSE_rounding_default( env );
      return dst;
   }

   if (e->tag == Iex_Get) {
      AMD64AMode* am = AMD64AMode_IR( e->Iex.Get.offset,
                                       hregAMD64_RBP() );
      HReg res = newVRegV(env);
      addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 4, res, am ));
      return res;
   }

   if (e->tag == Iex_Unop
       && e->Iex.Unop.op == Iop_ReinterpI32asF32) {
       /* Given an I32, produce an IEEE754 float with the same bit
          pattern. */
       HReg        dst    = newVRegV(env);
       HReg        src    = iselIntExpr_R(env, e->Iex.Unop.arg);
       AMD64AMode* m4_rsp = AMD64AMode_IR(-4, hregAMD64_RSP());
       addInstr(env, AMD64Instr_Store(4, src, m4_rsp));
       addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 4, dst, m4_rsp ));
       return dst;
   }

   if (e->tag == Iex_Binop && e->Iex.Binop.op == Iop_RoundF32toInt) {
      AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
      HReg        arg    = iselFltExpr(env, e->Iex.Binop.arg2);
      HReg        dst    = newVRegV(env);

      /* rf now holds the value to be rounded.  The first thing to do
         is set the FPU's rounding mode accordingly. */

      /* Set host x87 rounding mode */
      set_FPU_rounding_mode( env, e->Iex.Binop.arg1 );

      addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 4, arg, m8_rsp));
      addInstr(env, AMD64Instr_A87Free(1));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 4));
      addInstr(env, AMD64Instr_A87FpOp(Afp_ROUND));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, False/*pop*/, 4));
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 4, dst, m8_rsp));

      /* Restore default x87 rounding. */
      set_FPU_rounding_default( env );

      return dst;
   }

   if (e->tag == Iex_Unop && e->Iex.Unop.op == Iop_NegF32) {
      /* Sigh ... very rough code.  Could do much better. */
      /* Get the 128-bit literal 00---0 10---0 into a register
         and xor it with the value to be negated. */
      HReg r1  = newVRegI(env);
      HReg dst = newVRegV(env);
      HReg tmp = newVRegV(env);
      HReg src = iselFltExpr(env, e->Iex.Unop.arg);
      AMD64AMode* rsp0 = AMD64AMode_IR(0, hregAMD64_RSP());
      addInstr(env, mk_vMOVsd_RR(src,tmp));
      addInstr(env, AMD64Instr_Push(AMD64RMI_Imm(0)));
      addInstr(env, AMD64Instr_Imm64( 1ULL<<31, r1 ));
      addInstr(env, AMD64Instr_Push(AMD64RMI_Reg(r1)));
      addInstr(env, AMD64Instr_SseLdSt(True, 16, dst, rsp0));
      addInstr(env, AMD64Instr_SseReRg(Asse_XOR, tmp, dst));
      add_to_rsp(env, 16);
      return dst;
   }

   if (e->tag == Iex_Qop && e->Iex.Qop.details->op == Iop_MAddF32) {
      IRQop *qop = e->Iex.Qop.details;
      HReg dst  = newVRegV(env);
      HReg argX = iselFltExpr(env, qop->arg2);
      HReg argY = iselFltExpr(env, qop->arg3);
      HReg argZ = iselFltExpr(env, qop->arg4);
      /* XXXROUNDINGFIXME */
      /* set roundingmode here */
      /* subq $16, %rsp         -- make a space*/
      sub_from_rsp(env, 16);
      /* Prepare 4 arg regs:
         leaq 0(%rsp), %rdi
         leaq 4(%rsp), %rsi
         leaq 8(%rsp), %rdx
         leaq 12(%rsp), %rcx
      */
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, hregAMD64_RSP()),
                                     hregAMD64_RDI()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(4, hregAMD64_RSP()),
                                     hregAMD64_RSI()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(8, hregAMD64_RSP()),
                                     hregAMD64_RDX()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(12, hregAMD64_RSP()),
                                     hregAMD64_RCX()));
      /* Store the three args, at (%rsi), (%rdx) and (%rcx):
         movss  %argX, 0(%rsi)
         movss  %argY, 0(%rdx)
         movss  %argZ, 0(%rcx)
         */
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 4, argX,
                                       AMD64AMode_IR(0, hregAMD64_RSI())));
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 4, argY,
                                       AMD64AMode_IR(0, hregAMD64_RDX())));
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 4, argZ,
                                       AMD64AMode_IR(0, hregAMD64_RCX())));
      /* call the helper */
      addInstr(env, AMD64Instr_Call( Acc_ALWAYS,
                                     (ULong)(HWord)h_generic_calc_MAddF32,
                                     4, mk_RetLoc_simple(RLPri_None) ));
      /* fetch the result from memory, using %r_argp, which the
         register allocator will keep alive across the call. */
      addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 4, dst,
                                       AMD64AMode_IR(0, hregAMD64_RSP())));
      /* and finally, clear the space */
      add_to_rsp(env, 16);
      return dst;
   }

   ppIRExpr(e);
   vpanic("iselFltExpr_wrk");
}


/*---------------------------------------------------------*/
/*--- ISEL: Floating point expressions (64 bit)         ---*/
/*---------------------------------------------------------*/

/* Compute a 64-bit floating point value into the lower half of an xmm
   register, the identity of which is returned.  As with
   iselIntExpr_R, the returned reg will be virtual, and it must not be
   changed by subsequent code emitted by the caller.
*/

/* IEEE 754 formats.  From http://www.freesoft.org/CIE/RFC/1832/32.htm:

    Type                  S (1 bit)   E (11 bits)   F (52 bits)
    ----                  ---------   -----------   -----------
    signalling NaN        u           2047 (max)    .0uuuuu---u
                                                    (with at least
                                                     one 1 bit)
    quiet NaN             u           2047 (max)    .1uuuuu---u

    negative infinity     1           2047 (max)    .000000---0

    positive infinity     0           2047 (max)    .000000---0

    negative zero         1           0             .000000---0

    positive zero         0           0             .000000---0
*/

static HReg iselDblExpr ( ISelEnv* env, const IRExpr* e )
{
   HReg r = iselDblExpr_wrk( env, e );
#  if 0
   vex_printf("\n"); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(r) == HRcVec128);
   vassert(hregIsVirtual(r));
   return r;
}

/* DO NOT CALL THIS DIRECTLY */
static HReg iselDblExpr_wrk ( ISelEnv* env, const IRExpr* e )
{
   IRType ty = typeOfIRExpr(env->type_env,e);
   vassert(e);
   vassert(ty == Ity_F64);

   if (e->tag == Iex_RdTmp) {
      return lookupIRTemp(env, e->Iex.RdTmp.tmp);
   }

   if (e->tag == Iex_Const) {
      union { ULong u64; Double f64; } u;
      HReg res = newVRegV(env);
      HReg tmp = newVRegI(env);
      vassert(sizeof(u) == 8);
      vassert(sizeof(u.u64) == 8);
      vassert(sizeof(u.f64) == 8);

      if (e->Iex.Const.con->tag == Ico_F64) {
         u.f64 = e->Iex.Const.con->Ico.F64;
      }
      else if (e->Iex.Const.con->tag == Ico_F64i) {
         u.u64 = e->Iex.Const.con->Ico.F64i;
      }
      else
         vpanic("iselDblExpr(amd64): const");

      addInstr(env, AMD64Instr_Imm64(u.u64, tmp));
      addInstr(env, AMD64Instr_Push(AMD64RMI_Reg(tmp)));
      addInstr(env, AMD64Instr_SseLdSt(
                       True/*load*/, 8, res, 
                       AMD64AMode_IR(0, hregAMD64_RSP())
              ));
      add_to_rsp(env, 8);
      return res;
   }

   if (e->tag == Iex_Load && e->Iex.Load.end == Iend_LE) {
      AMD64AMode* am;
      HReg res = newVRegV(env);
      vassert(e->Iex.Load.ty == Ity_F64);
      am = iselIntExpr_AMode(env, e->Iex.Load.addr);
      addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 8, res, am ));
      return res;
   }

   if (e->tag == Iex_Get) {
      AMD64AMode* am = AMD64AMode_IR( e->Iex.Get.offset,
                                      hregAMD64_RBP() );
      HReg res = newVRegV(env);
      addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 8, res, am ));
      return res;
   }

   if (e->tag == Iex_GetI) {
      AMD64AMode* am 
         = genGuestArrayOffset(
              env, e->Iex.GetI.descr, 
                   e->Iex.GetI.ix, e->Iex.GetI.bias );
      HReg res = newVRegV(env);
      addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 8, res, am ));
      return res;
   }

   if (e->tag == Iex_Triop) {
      IRTriop *triop = e->Iex.Triop.details;
      AMD64SseOp op = Asse_INVALID;
      switch (triop->op) {
         case Iop_AddF64: op = Asse_ADDF; break;
         case Iop_SubF64: op = Asse_SUBF; break;
         case Iop_MulF64: op = Asse_MULF; break;
         case Iop_DivF64: op = Asse_DIVF; break;
         default: break;
      }
      if (op != Asse_INVALID) {
         HReg dst  = newVRegV(env);
         HReg argL = iselDblExpr(env, triop->arg2);
         HReg argR = iselDblExpr(env, triop->arg3);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, AMD64Instr_Sse64FLo(op, argR, dst));
         return dst;
      }
   }

   if (e->tag == Iex_Qop && e->Iex.Qop.details->op == Iop_MAddF64) {
      IRQop *qop = e->Iex.Qop.details;
      HReg dst  = newVRegV(env);
      HReg argX = iselDblExpr(env, qop->arg2);
      HReg argY = iselDblExpr(env, qop->arg3);
      HReg argZ = iselDblExpr(env, qop->arg4);
      /* XXXROUNDINGFIXME */
      /* set roundingmode here */
      /* subq $32, %rsp         -- make a space*/
      sub_from_rsp(env, 32);
      /* Prepare 4 arg regs:
         leaq 0(%rsp), %rdi
         leaq 8(%rsp), %rsi
         leaq 16(%rsp), %rdx
         leaq 24(%rsp), %rcx
      */
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, hregAMD64_RSP()),
                                     hregAMD64_RDI()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(8, hregAMD64_RSP()),
                                     hregAMD64_RSI()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(16, hregAMD64_RSP()),
                                     hregAMD64_RDX()));
      addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(24, hregAMD64_RSP()),
                                     hregAMD64_RCX()));
      /* Store the three args, at (%rsi), (%rdx) and (%rcx):
         movsd  %argX, 0(%rsi)
         movsd  %argY, 0(%rdx)
         movsd  %argZ, 0(%rcx)
         */
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 8, argX,
                                       AMD64AMode_IR(0, hregAMD64_RSI())));
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 8, argY,
                                       AMD64AMode_IR(0, hregAMD64_RDX())));
      addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 8, argZ,
                                       AMD64AMode_IR(0, hregAMD64_RCX())));
      /* call the helper */
      addInstr(env, AMD64Instr_Call( Acc_ALWAYS,
                                     (ULong)(HWord)h_generic_calc_MAddF64,
                                     4, mk_RetLoc_simple(RLPri_None) ));
      /* fetch the result from memory, using %r_argp, which the
         register allocator will keep alive across the call. */
      addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 8, dst,
                                       AMD64AMode_IR(0, hregAMD64_RSP())));
      /* and finally, clear the space */
      add_to_rsp(env, 32);
      return dst;
   }

   if (e->tag == Iex_Binop && e->Iex.Binop.op == Iop_RoundF64toInt) {
      AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
      HReg        arg    = iselDblExpr(env, e->Iex.Binop.arg2);
      HReg        dst    = newVRegV(env);

      /* rf now holds the value to be rounded.  The first thing to do
         is set the FPU's rounding mode accordingly. */

      /* Set host x87 rounding mode */
      set_FPU_rounding_mode( env, e->Iex.Binop.arg1 );

      addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, arg, m8_rsp));
      addInstr(env, AMD64Instr_A87Free(1));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));
      addInstr(env, AMD64Instr_A87FpOp(Afp_ROUND));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, False/*pop*/, 8));
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 8, dst, m8_rsp));

      /* Restore default x87 rounding. */
      set_FPU_rounding_default( env );

      return dst;
   }

   IRTriop *triop = e->Iex.Triop.details;
   if (e->tag == Iex_Triop 
       && (triop->op == Iop_ScaleF64
           || triop->op == Iop_AtanF64
           || triop->op == Iop_Yl2xF64
           || triop->op == Iop_Yl2xp1F64
           || triop->op == Iop_PRemF64
           || triop->op == Iop_PRem1F64)
      ) {
      AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
      HReg        arg1   = iselDblExpr(env, triop->arg2);
      HReg        arg2   = iselDblExpr(env, triop->arg3);
      HReg        dst    = newVRegV(env);
      Bool     arg2first = toBool(triop->op == Iop_ScaleF64 
                                  || triop->op == Iop_PRemF64
                                  || triop->op == Iop_PRem1F64);
      addInstr(env, AMD64Instr_A87Free(2));

      /* one arg -> top of x87 stack */
      addInstr(env, AMD64Instr_SseLdSt(
                       False/*store*/, 8, arg2first ? arg2 : arg1, m8_rsp));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));

      /* other arg -> top of x87 stack */
      addInstr(env, AMD64Instr_SseLdSt(
                       False/*store*/, 8, arg2first ? arg1 : arg2, m8_rsp));
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));

      /* do it */
      /* XXXROUNDINGFIXME */
      /* set roundingmode here */
      switch (triop->op) {
         case Iop_ScaleF64: 
            addInstr(env, AMD64Instr_A87FpOp(Afp_SCALE));
            break;
         case Iop_AtanF64: 
            addInstr(env, AMD64Instr_A87FpOp(Afp_ATAN));
            break;
         case Iop_Yl2xF64: 
            addInstr(env, AMD64Instr_A87FpOp(Afp_YL2X));
            break;
         case Iop_Yl2xp1F64: 
            addInstr(env, AMD64Instr_A87FpOp(Afp_YL2XP1));
            break;
         case Iop_PRemF64:
            addInstr(env, AMD64Instr_A87FpOp(Afp_PREM));
            break;
         case Iop_PRem1F64:
            addInstr(env, AMD64Instr_A87FpOp(Afp_PREM1));
            break;
         default: 
            vassert(0);
      }

      /* save result */
      addInstr(env, AMD64Instr_A87PushPop(m8_rsp, False/*pop*/, 8));
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 8, dst, m8_rsp));
      return dst;
   }

   if (e->tag == Iex_Binop && e->Iex.Binop.op == Iop_I64StoF64) {
      HReg dst = newVRegV(env);
      HReg src = iselIntExpr_R(env, e->Iex.Binop.arg2);
      set_SSE_rounding_mode( env, e->Iex.Binop.arg1 );
      addInstr(env, AMD64Instr_SseSI2SF( 8, 8, src, dst ));
      set_SSE_rounding_default( env );
      return dst;
   }

   if (e->tag == Iex_Unop && e->Iex.Unop.op == Iop_I32StoF64) {
      HReg dst = newVRegV(env);
      HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
      set_SSE_rounding_default( env );
      addInstr(env, AMD64Instr_SseSI2SF( 4, 8, src, dst ));
      return dst;
   }

   if (e->tag == Iex_Unop 
       && (e->Iex.Unop.op == Iop_NegF64
           || e->Iex.Unop.op == Iop_AbsF64)) {
      /* Sigh ... very rough code.  Could do much better. */
      /* Get the 128-bit literal 00---0 10---0 into a register
         and xor/nand it with the value to be negated. */
      HReg r1  = newVRegI(env);
      HReg dst = newVRegV(env);
      HReg tmp = newVRegV(env);
      HReg src = iselDblExpr(env, e->Iex.Unop.arg);
      AMD64AMode* rsp0 = AMD64AMode_IR(0, hregAMD64_RSP());
      addInstr(env, mk_vMOVsd_RR(src,tmp));
      addInstr(env, AMD64Instr_Push(AMD64RMI_Imm(0)));
      addInstr(env, AMD64Instr_Imm64( 1ULL<<63, r1 ));
      addInstr(env, AMD64Instr_Push(AMD64RMI_Reg(r1)));
      addInstr(env, AMD64Instr_SseLdSt(True, 16, dst, rsp0));

      if (e->Iex.Unop.op == Iop_NegF64)
         addInstr(env, AMD64Instr_SseReRg(Asse_XOR, tmp, dst));
      else
         addInstr(env, AMD64Instr_SseReRg(Asse_ANDN, tmp, dst));

      add_to_rsp(env, 16);
      return dst;
   }

   if (e->tag == Iex_Binop) {
      A87FpOp fpop = Afp_INVALID;
      switch (e->Iex.Binop.op) {
         case Iop_SqrtF64: fpop = Afp_SQRT; break;
         case Iop_SinF64:  fpop = Afp_SIN;  break;
         case Iop_CosF64:  fpop = Afp_COS;  break;
         case Iop_TanF64:  fpop = Afp_TAN;  break;
         case Iop_2xm1F64: fpop = Afp_2XM1; break;
         default: break;
      }
      if (fpop != Afp_INVALID) {
         AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
         HReg        arg    = iselDblExpr(env, e->Iex.Binop.arg2);
         HReg        dst    = newVRegV(env);
         Int     nNeeded    = e->Iex.Binop.op==Iop_TanF64 ? 2 : 1;
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, arg, m8_rsp));
         addInstr(env, AMD64Instr_A87Free(nNeeded));
         addInstr(env, AMD64Instr_A87PushPop(m8_rsp, True/*push*/, 8));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         /* Note that AMD64Instr_A87FpOp(Afp_TAN) sets the condition
            codes.  I don't think that matters, since this insn
            selector never generates such an instruction intervening
            between an flag-setting instruction and a flag-using
            instruction. */
         addInstr(env, AMD64Instr_A87FpOp(fpop));
         addInstr(env, AMD64Instr_A87PushPop(m8_rsp, False/*pop*/, 8));
         addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 8, dst, m8_rsp));
         return dst;
      }
   }

   if (e->tag == Iex_Unop) {
      switch (e->Iex.Unop.op) {
//..          case Iop_I32toF64: {
//..             HReg dst = newVRegF(env);
//..             HReg ri  = iselIntExpr_R(env, e->Iex.Unop.arg);
//..             addInstr(env, X86Instr_Push(X86RMI_Reg(ri)));
//..             set_FPU_rounding_default(env);
//..             addInstr(env, X86Instr_FpLdStI(
//..                              True/*load*/, 4, dst, 
//..                              X86AMode_IR(0, hregX86_ESP())));
//..             add_to_esp(env, 4);
//..             return dst;
//..          }
         case Iop_ReinterpI64asF64: {
            /* Given an I64, produce an IEEE754 double with the same
               bit pattern. */
            AMD64AMode* m8_rsp = AMD64AMode_IR(-8, hregAMD64_RSP());
            HReg        dst    = newVRegV(env);
            AMD64RI*    src    = iselIntExpr_RI(env, e->Iex.Unop.arg);
            /* paranoia */
            set_SSE_rounding_default(env);
            addInstr(env, AMD64Instr_Alu64M(Aalu_MOV, src, m8_rsp));
            addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 8, dst, m8_rsp));
            return dst;
         }
         case Iop_F32toF64: {
            HReg f32;
            HReg f64 = newVRegV(env);
            /* this shouldn't be necessary, but be paranoid ... */
            set_SSE_rounding_default(env);
            f32 = iselFltExpr(env, e->Iex.Unop.arg);
            addInstr(env, AMD64Instr_SseSDSS(False/*S->D*/, f32, f64));
            return f64;
         }
         default: 
            break;
      }
   }

   /* --------- MULTIPLEX --------- */
   if (e->tag == Iex_ITE) { // VFD
      HReg r1, r0, dst;
      vassert(ty == Ity_F64);
      vassert(typeOfIRExpr(env->type_env,e->Iex.ITE.cond) == Ity_I1);
      r1  = iselDblExpr(env, e->Iex.ITE.iftrue);
      r0  = iselDblExpr(env, e->Iex.ITE.iffalse);
      dst = newVRegV(env);
      addInstr(env, mk_vMOVsd_RR(r1,dst));
      AMD64CondCode cc = iselCondCode(env, e->Iex.ITE.cond);
      addInstr(env, AMD64Instr_SseCMov(cc ^ 1, r0, dst));
      return dst;
   }

   ppIRExpr(e);
   vpanic("iselDblExpr_wrk");
}


/*---------------------------------------------------------*/
/*--- ISEL: SIMD (Vector) expressions, 128 bit.         ---*/
/*---------------------------------------------------------*/

static HReg iselVecExpr ( ISelEnv* env, const IRExpr* e )
{
   HReg r = iselVecExpr_wrk( env, e );
#  if 0
   vex_printf("\n"); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(r) == HRcVec128);
   vassert(hregIsVirtual(r));
   return r;
}


/* DO NOT CALL THIS DIRECTLY */
static HReg iselVecExpr_wrk ( ISelEnv* env, const IRExpr* e )
{
   HWord      fn = 0; /* address of helper fn, if required */
   Bool       arg1isEReg = False;
   AMD64SseOp op = Asse_INVALID;
   vassert(e);
   IRType ty = typeOfIRExpr(env->type_env, e);
   vassert(ty == Ity_V128);
   UInt laneBits = 0;

   if (e->tag == Iex_RdTmp) {
      return lookupIRTemp(env, e->Iex.RdTmp.tmp);
   }

   if (e->tag == Iex_Get) {
      HReg dst = newVRegV(env);
      addInstr(env, AMD64Instr_SseLdSt(
                       True/*load*/, 
                       16,
                       dst,
                       AMD64AMode_IR(e->Iex.Get.offset, hregAMD64_RBP())
                    )
              );
      return dst;
   }

   if (e->tag == Iex_Load && e->Iex.Load.end == Iend_LE) {
      HReg        dst = newVRegV(env);
      AMD64AMode* am  = iselIntExpr_AMode(env, e->Iex.Load.addr);
      addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 16, dst, am ));
      return dst;
   }

   if (e->tag == Iex_Const) {
      HReg dst = newVRegV(env);
      vassert(e->Iex.Const.con->tag == Ico_V128);
      switch (e->Iex.Const.con->Ico.V128) {
         case 0x0000:
            dst = generate_zeroes_V128(env);
            break;
         case 0xFFFF:
            dst = generate_ones_V128(env);
            break;
         default: {
            AMD64AMode* rsp0 = AMD64AMode_IR(0, hregAMD64_RSP());
            /* do push_uimm64 twice, first time for the high-order half. */
            push_uimm64(env, bitmask8_to_bytemask64(
                                (e->Iex.Const.con->Ico.V128 >> 8) & 0xFF
                       ));
            push_uimm64(env, bitmask8_to_bytemask64(
                                (e->Iex.Const.con->Ico.V128 >> 0) & 0xFF
                       ));
            addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 16, dst, rsp0 ));
            add_to_rsp(env, 16);
            break;
         }
      }
      return dst;
   }

   if (e->tag == Iex_Unop) {
   switch (e->Iex.Unop.op) {

      case Iop_NotV128: {
         HReg arg = iselVecExpr(env, e->Iex.Unop.arg);
         return do_sse_NotV128(env, arg);
      }

      case Iop_CmpNEZ64x2: {
         /* We can use SSE2 instructions for this. */
         /* Ideally, we want to do a 64Ix2 comparison against zero of
            the operand.  Problem is no such insn exists.  Solution
            therefore is to do a 32Ix4 comparison instead, and bitwise-
            negate (NOT) the result.  Let a,b,c,d be 32-bit lanes, and 
            let the not'd result of this initial comparison be a:b:c:d.
            What we need to compute is (a|b):(a|b):(c|d):(c|d).  So, use
            pshufd to create a value b:a:d:c, and OR that with a:b:c:d,
            giving the required result.

            The required selection sequence is 2,3,0,1, which
            according to Intel's documentation means the pshufd
            literal value is 0xB1, that is, 
            (2 << 6) | (3 << 4) | (0 << 2) | (1 << 0) 
         */
         HReg arg  = iselVecExpr(env, e->Iex.Unop.arg);
         HReg tmp  = generate_zeroes_V128(env);
         HReg dst  = newVRegV(env);
         addInstr(env, AMD64Instr_SseReRg(Asse_CMPEQ32, arg, tmp));
         tmp = do_sse_NotV128(env, tmp);
         addInstr(env, AMD64Instr_SseShuf(0xB1, tmp, dst));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dst));
         return dst;
      }

      case Iop_CmpNEZ32x4: op = Asse_CMPEQ32; goto do_CmpNEZ_vector;
      case Iop_CmpNEZ16x8: op = Asse_CMPEQ16; goto do_CmpNEZ_vector;
      case Iop_CmpNEZ8x16: op = Asse_CMPEQ8;  goto do_CmpNEZ_vector;
      do_CmpNEZ_vector:
      {
         HReg arg  = iselVecExpr(env, e->Iex.Unop.arg);
         HReg tmp  = newVRegV(env);
         HReg zero = generate_zeroes_V128(env);
         HReg dst;
         addInstr(env, mk_vMOVsd_RR(arg, tmp));
         addInstr(env, AMD64Instr_SseReRg(op, zero, tmp));
         dst = do_sse_NotV128(env, tmp);
         return dst;
      }

      case Iop_RecipEst32Fx4: op = Asse_RCPF;   goto do_32Fx4_unary;
      case Iop_RSqrtEst32Fx4: op = Asse_RSQRTF; goto do_32Fx4_unary;
      do_32Fx4_unary:
      {
         HReg arg = iselVecExpr(env, e->Iex.Unop.arg);
         HReg dst = newVRegV(env);
         addInstr(env, AMD64Instr_Sse32Fx4(op, arg, dst));
         return dst;
      }

      case Iop_RecipEst32F0x4: op = Asse_RCPF;   goto do_32F0x4_unary;
      case Iop_RSqrtEst32F0x4: op = Asse_RSQRTF; goto do_32F0x4_unary;
      case Iop_Sqrt32F0x4:     op = Asse_SQRTF;  goto do_32F0x4_unary;
      do_32F0x4_unary:
      {
         /* A bit subtle.  We have to copy the arg to the result
            register first, because actually doing the SSE scalar insn
            leaves the upper 3/4 of the destination register
            unchanged.  Whereas the required semantics of these
            primops is that the upper 3/4 is simply copied in from the
            argument. */
         HReg arg = iselVecExpr(env, e->Iex.Unop.arg);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(arg, dst));
         addInstr(env, AMD64Instr_Sse32FLo(op, arg, dst));
         return dst;
      }

      case Iop_Sqrt64F0x2:  op = Asse_SQRTF;  goto do_64F0x2_unary;
      do_64F0x2_unary:
      {
         /* A bit subtle.  We have to copy the arg to the result
            register first, because actually doing the SSE scalar insn
            leaves the upper half of the destination register
            unchanged.  Whereas the required semantics of these
            primops is that the upper half is simply copied in from the
            argument. */
         HReg arg = iselVecExpr(env, e->Iex.Unop.arg);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(arg, dst));
         addInstr(env, AMD64Instr_Sse64FLo(op, arg, dst));
         return dst;
      }

      case Iop_32UtoV128: {
         // FIXME maybe just use MOVQ here?
         HReg        dst     = newVRegV(env);
         AMD64AMode* rsp_m32 = AMD64AMode_IR(-32, hregAMD64_RSP());
         AMD64RI*    ri      = iselIntExpr_RI(env, e->Iex.Unop.arg);
         addInstr(env, AMD64Instr_Alu64M(Aalu_MOV, ri, rsp_m32));
         addInstr(env, AMD64Instr_SseLdzLO(4, dst, rsp_m32));
         return dst;
      }

      case Iop_64UtoV128: {
         // FIXME maybe just use MOVQ here?
         HReg        dst  = newVRegV(env);
         AMD64AMode* rsp0 = AMD64AMode_IR(0, hregAMD64_RSP());
         AMD64RMI*   rmi  = iselIntExpr_RMI(env, e->Iex.Unop.arg);
         addInstr(env, AMD64Instr_Push(rmi));
         addInstr(env, AMD64Instr_SseLdzLO(8, dst, rsp0));
         add_to_rsp(env, 8);
         return dst;
      }

      case Iop_V256toV128_0:
      case Iop_V256toV128_1: {
         HReg vHi, vLo;
         iselDVecExpr(&vHi, &vLo, env, e->Iex.Unop.arg);
         return (e->Iex.Unop.op == Iop_V256toV128_1) ? vHi : vLo;
      }

      case Iop_F16toF32x4: {
         if (env->hwcaps & VEX_HWCAPS_AMD64_F16C) {
            HReg src = iselIntExpr_R(env, e->Iex.Unop.arg);
            HReg dst = newVRegV(env);
            addInstr(env, AMD64Instr_SseMOVQ(src, dst, /*toXMM=*/True));
            addInstr(env, AMD64Instr_Sse32Fx4(Asse_F16toF32, dst, dst));
            return dst;
         }
         break;
      }

      default:
         break;
   } /* switch (e->Iex.Unop.op) */
   } /* if (e->tag == Iex_Unop) */

   if (e->tag == Iex_Binop) {
   switch (e->Iex.Binop.op) {

      case Iop_Sqrt64Fx2:
      case Iop_Sqrt32Fx4: {
         /* :: (rmode, vec) -> vec */
         HReg arg = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, (e->Iex.Binop.op == Iop_Sqrt64Fx2 
                           ? AMD64Instr_Sse64Fx2 : AMD64Instr_Sse32Fx4)
                       (Asse_SQRTF, arg, dst));
         return dst;
      }

      /* FIXME: could we generate MOVQ here? */
      case Iop_SetV128lo64: {
         HReg dst  = newVRegV(env);
         HReg srcV = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg srcI = iselIntExpr_R(env, e->Iex.Binop.arg2);
         AMD64AMode* rsp_m16 = AMD64AMode_IR(-16, hregAMD64_RSP());
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, srcV, rsp_m16));
         addInstr(env, AMD64Instr_Alu64M(Aalu_MOV, AMD64RI_Reg(srcI), rsp_m16));
         addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, dst, rsp_m16));
         return dst;
      }

      /* FIXME: could we generate MOVD here? */
      case Iop_SetV128lo32: {
         HReg dst  = newVRegV(env);
         HReg srcV = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg srcI = iselIntExpr_R(env, e->Iex.Binop.arg2);
         AMD64AMode* rsp_m16 = AMD64AMode_IR(-16, hregAMD64_RSP());
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, srcV, rsp_m16));
         addInstr(env, AMD64Instr_Store(4, srcI, rsp_m16));
         addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, dst, rsp_m16));
         return dst;
      }

      case Iop_64HLtoV128: {
         const IRExpr* arg1 = e->Iex.Binop.arg1;
         const IRExpr* arg2 = e->Iex.Binop.arg2;
         HReg dst = newVRegV(env);
         HReg tmp = newVRegV(env);
         HReg qHi = iselIntExpr_R(env, arg1);
         // If the args are trivially the same (tmp or const), use the same
         // source register for both, and only one movq since those are
         // (relatively) expensive.
         if (areAtomsAndEqual(arg1, arg2)) {
            addInstr(env, AMD64Instr_SseMOVQ(qHi, dst, True/*toXMM*/));
            addInstr(env, mk_vMOVsd_RR(dst, tmp));
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dst));
            addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dst));
         } else {
            HReg qLo = iselIntExpr_R(env, arg2);
            addInstr(env, AMD64Instr_SseMOVQ(qHi, dst, True/*toXMM*/));
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dst));
            addInstr(env, AMD64Instr_SseMOVQ(qLo, tmp, True/*toXMM*/));
            addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dst));
         }
         return dst;
      }

      case Iop_CmpEQ32Fx4: op = Asse_CMPEQF; goto do_32Fx4;
      case Iop_CmpLT32Fx4: op = Asse_CMPLTF; goto do_32Fx4;
      case Iop_CmpLE32Fx4: op = Asse_CMPLEF; goto do_32Fx4;
      case Iop_CmpUN32Fx4: op = Asse_CMPUNF; goto do_32Fx4;
      case Iop_Max32Fx4:   op = Asse_MAXF;   goto do_32Fx4;
      case Iop_Min32Fx4:   op = Asse_MINF;   goto do_32Fx4;
      do_32Fx4:
      {
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         addInstr(env, AMD64Instr_Sse32Fx4(op, argR, dst));
         return dst;
      }

      case Iop_CmpEQ64Fx2: op = Asse_CMPEQF; goto do_64Fx2;
      case Iop_CmpLT64Fx2: op = Asse_CMPLTF; goto do_64Fx2;
      case Iop_CmpLE64Fx2: op = Asse_CMPLEF; goto do_64Fx2;
      case Iop_CmpUN64Fx2: op = Asse_CMPUNF; goto do_64Fx2;
      case Iop_Max64Fx2:   op = Asse_MAXF;   goto do_64Fx2;
      case Iop_Min64Fx2:   op = Asse_MINF;   goto do_64Fx2;
      do_64Fx2:
      {
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         addInstr(env, AMD64Instr_Sse64Fx2(op, argR, dst));
         return dst;
      }

      case Iop_CmpEQ32F0x4: op = Asse_CMPEQF; goto do_32F0x4;
      case Iop_CmpLT32F0x4: op = Asse_CMPLTF; goto do_32F0x4;
      case Iop_CmpLE32F0x4: op = Asse_CMPLEF; goto do_32F0x4;
      case Iop_CmpUN32F0x4: op = Asse_CMPUNF; goto do_32F0x4;
      case Iop_Add32F0x4:   op = Asse_ADDF;   goto do_32F0x4;
      case Iop_Div32F0x4:   op = Asse_DIVF;   goto do_32F0x4;
      case Iop_Max32F0x4:   op = Asse_MAXF;   goto do_32F0x4;
      case Iop_Min32F0x4:   op = Asse_MINF;   goto do_32F0x4;
      case Iop_Mul32F0x4:   op = Asse_MULF;   goto do_32F0x4;
      case Iop_Sub32F0x4:   op = Asse_SUBF;   goto do_32F0x4;
      do_32F0x4: {
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         addInstr(env, AMD64Instr_Sse32FLo(op, argR, dst));
         return dst;
      }

      case Iop_CmpEQ64F0x2: op = Asse_CMPEQF; goto do_64F0x2;
      case Iop_CmpLT64F0x2: op = Asse_CMPLTF; goto do_64F0x2;
      case Iop_CmpLE64F0x2: op = Asse_CMPLEF; goto do_64F0x2;
      case Iop_CmpUN64F0x2: op = Asse_CMPUNF; goto do_64F0x2;
      case Iop_Add64F0x2:   op = Asse_ADDF;   goto do_64F0x2;
      case Iop_Div64F0x2:   op = Asse_DIVF;   goto do_64F0x2;
      case Iop_Max64F0x2:   op = Asse_MAXF;   goto do_64F0x2;
      case Iop_Min64F0x2:   op = Asse_MINF;   goto do_64F0x2;
      case Iop_Mul64F0x2:   op = Asse_MULF;   goto do_64F0x2;
      case Iop_Sub64F0x2:   op = Asse_SUBF;   goto do_64F0x2;
      do_64F0x2: {
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         addInstr(env, AMD64Instr_Sse64FLo(op, argR, dst));
         return dst;
      }

      case Iop_PermOrZero8x16:
         if (env->hwcaps & VEX_HWCAPS_AMD64_SSSE3) {
            op = Asse_PSHUFB;
            goto do_SseReRg;
         }
         // Otherwise we'll have to generate a call to
         // h_generic_calc_PermOrZero8x16 (ATK).  But that would only be for a
         // host which doesn't have SSSE3, in which case we don't expect this
         // IROp to enter the compilation pipeline in the first place.
         break;

      case Iop_PwExtUSMulQAdd8x16:
         if (env->hwcaps & VEX_HWCAPS_AMD64_SSSE3) {
            op = Asse_PMADDUBSW;
            goto do_SseReRg;
         }
         break;

      case Iop_QNarrowBin32Sto16Sx8: 
         op = Asse_PACKSSD; arg1isEReg = True; goto do_SseReRg;
      case Iop_QNarrowBin16Sto8Sx16: 
         op = Asse_PACKSSW; arg1isEReg = True; goto do_SseReRg;
      case Iop_QNarrowBin16Sto8Ux16: 
         op = Asse_PACKUSW; arg1isEReg = True; goto do_SseReRg;

      case Iop_InterleaveHI8x16: 
         op = Asse_UNPCKHB; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveHI16x8: 
         op = Asse_UNPCKHW; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveHI32x4: 
         op = Asse_UNPCKHD; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveHI64x2: 
         op = Asse_UNPCKHQ; arg1isEReg = True; goto do_SseReRg;

      case Iop_InterleaveLO8x16: 
         op = Asse_UNPCKLB; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveLO16x8: 
         op = Asse_UNPCKLW; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveLO32x4: 
         op = Asse_UNPCKLD; arg1isEReg = True; goto do_SseReRg;
      case Iop_InterleaveLO64x2: 
         op = Asse_UNPCKLQ; arg1isEReg = True; goto do_SseReRg;

      case Iop_AndV128:    op = Asse_AND;      goto do_SseReRg;
      case Iop_OrV128:     op = Asse_OR;       goto do_SseReRg;
      case Iop_XorV128:    op = Asse_XOR;      goto do_SseReRg;
      case Iop_Add8x16:    op = Asse_ADD8;     goto do_SseReRg;
      case Iop_Add16x8:    op = Asse_ADD16;    goto do_SseReRg;
      case Iop_Add32x4:    op = Asse_ADD32;    goto do_SseReRg;
      case Iop_Add64x2:    op = Asse_ADD64;    goto do_SseReRg;
      case Iop_QAdd8Sx16:  op = Asse_QADD8S;   goto do_SseReRg;
      case Iop_QAdd16Sx8:  op = Asse_QADD16S;  goto do_SseReRg;
      case Iop_QAdd8Ux16:  op = Asse_QADD8U;   goto do_SseReRg;
      case Iop_QAdd16Ux8:  op = Asse_QADD16U;  goto do_SseReRg;
      case Iop_Avg8Ux16:   op = Asse_AVG8U;    goto do_SseReRg;
      case Iop_Avg16Ux8:   op = Asse_AVG16U;   goto do_SseReRg;
      case Iop_CmpEQ8x16:  op = Asse_CMPEQ8;   goto do_SseReRg;
      case Iop_CmpEQ16x8:  op = Asse_CMPEQ16;  goto do_SseReRg;
      case Iop_CmpEQ32x4:  op = Asse_CMPEQ32;  goto do_SseReRg;
      case Iop_CmpGT8Sx16: op = Asse_CMPGT8S;  goto do_SseReRg;
      case Iop_CmpGT16Sx8: op = Asse_CMPGT16S; goto do_SseReRg;
      case Iop_CmpGT32Sx4: op = Asse_CMPGT32S; goto do_SseReRg;
      case Iop_Max16Sx8:   op = Asse_MAX16S;   goto do_SseReRg;
      case Iop_Max8Ux16:   op = Asse_MAX8U;    goto do_SseReRg;
      case Iop_Min16Sx8:   op = Asse_MIN16S;   goto do_SseReRg;
      case Iop_Min8Ux16:   op = Asse_MIN8U;    goto do_SseReRg;
      case Iop_MulHi16Ux8: op = Asse_MULHI16U; goto do_SseReRg;
      case Iop_MulHi16Sx8: op = Asse_MULHI16S; goto do_SseReRg;
      case Iop_Mul16x8:    op = Asse_MUL16;    goto do_SseReRg;
      case Iop_Sub8x16:    op = Asse_SUB8;     goto do_SseReRg;
      case Iop_Sub16x8:    op = Asse_SUB16;    goto do_SseReRg;
      case Iop_Sub32x4:    op = Asse_SUB32;    goto do_SseReRg;
      case Iop_Sub64x2:    op = Asse_SUB64;    goto do_SseReRg;
      case Iop_QSub8Sx16:  op = Asse_QSUB8S;   goto do_SseReRg;
      case Iop_QSub16Sx8:  op = Asse_QSUB16S;  goto do_SseReRg;
      case Iop_QSub8Ux16:  op = Asse_QSUB8U;   goto do_SseReRg;
      case Iop_QSub16Ux8:  op = Asse_QSUB16U;  goto do_SseReRg;
      do_SseReRg: {
         HReg arg1 = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg arg2 = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         if (arg1isEReg) {
            addInstr(env, mk_vMOVsd_RR(arg2, dst));
            addInstr(env, AMD64Instr_SseReRg(op, arg1, dst));
         } else {
            addInstr(env, mk_vMOVsd_RR(arg1, dst));
            addInstr(env, AMD64Instr_SseReRg(op, arg2, dst));
         }
         return dst;
      }

      case Iop_ShlN16x8: laneBits = 16; op = Asse_SHL16; goto do_SseShift;
      case Iop_ShlN32x4: laneBits = 32; op = Asse_SHL32; goto do_SseShift;
      case Iop_ShlN64x2: laneBits = 64; op = Asse_SHL64; goto do_SseShift;
      case Iop_SarN16x8: laneBits = 16; op = Asse_SAR16; goto do_SseShift;
      case Iop_SarN32x4: laneBits = 32; op = Asse_SAR32; goto do_SseShift;
      case Iop_ShrN16x8: laneBits = 16; op = Asse_SHR16; goto do_SseShift;
      case Iop_ShrN32x4: laneBits = 32; op = Asse_SHR32; goto do_SseShift;
      case Iop_ShrN64x2: laneBits = 64; op = Asse_SHR64; goto do_SseShift;
      do_SseShift: {
         HReg dst  = newVRegV(env);
         HReg greg = iselVecExpr(env, e->Iex.Binop.arg1);
         /* If it's a shift by an in-range immediate, generate a single
            instruction. */
         if (e->Iex.Binop.arg2->tag == Iex_Const) {
            IRConst* c = e->Iex.Binop.arg2->Iex.Const.con;
            vassert(c->tag == Ico_U8);
            UInt shift = c->Ico.U8;
            if (shift < laneBits) {
               addInstr(env, mk_vMOVsd_RR(greg, dst));
               addInstr(env, AMD64Instr_SseShiftN(op, shift, dst));
               return dst;
            }
         }
         /* Otherwise we have to do it the longwinded way. */
         AMD64RMI*   rmi  = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
         AMD64AMode* rsp0 = AMD64AMode_IR(0, hregAMD64_RSP());
         HReg        ereg = newVRegV(env);
         addInstr(env, AMD64Instr_Push(AMD64RMI_Imm(0)));
         addInstr(env, AMD64Instr_Push(rmi));
         addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, ereg, rsp0));
         addInstr(env, mk_vMOVsd_RR(greg, dst));
         addInstr(env, AMD64Instr_SseReRg(op, ereg, dst));
         add_to_rsp(env, 16);
         return dst;
      }

      case Iop_Mul32x4:    fn = (HWord)h_generic_calc_Mul32x4;
                           goto do_SseAssistedBinary;
      case Iop_Max32Sx4:   fn = (HWord)h_generic_calc_Max32Sx4;
                           goto do_SseAssistedBinary;
      case Iop_Min32Sx4:   fn = (HWord)h_generic_calc_Min32Sx4;
                           goto do_SseAssistedBinary;
      case Iop_Max32Ux4:   fn = (HWord)h_generic_calc_Max32Ux4;
                           goto do_SseAssistedBinary;
      case Iop_Min32Ux4:   fn = (HWord)h_generic_calc_Min32Ux4;
                           goto do_SseAssistedBinary;
      case Iop_Max16Ux8:   fn = (HWord)h_generic_calc_Max16Ux8;
                           goto do_SseAssistedBinary;
      case Iop_Min16Ux8:   fn = (HWord)h_generic_calc_Min16Ux8;
                           goto do_SseAssistedBinary;
      case Iop_Max8Sx16:   fn = (HWord)h_generic_calc_Max8Sx16;
                           goto do_SseAssistedBinary;
      case Iop_Min8Sx16:   fn = (HWord)h_generic_calc_Min8Sx16;
                           goto do_SseAssistedBinary;
      case Iop_CmpEQ64x2:  fn = (HWord)h_generic_calc_CmpEQ64x2;
                           goto do_SseAssistedBinary;
      case Iop_CmpGT64Sx2: fn = (HWord)h_generic_calc_CmpGT64Sx2;
                           goto do_SseAssistedBinary;
      case Iop_Perm32x4:   fn = (HWord)h_generic_calc_Perm32x4;
                           goto do_SseAssistedBinary;
      case Iop_QNarrowBin32Sto16Ux8:
                           fn = (HWord)h_generic_calc_QNarrowBin32Sto16Ux8;
                           goto do_SseAssistedBinary;
      case Iop_NarrowBin16to8x16:
                           fn = (HWord)h_generic_calc_NarrowBin16to8x16;
                           goto do_SseAssistedBinary;
      case Iop_NarrowBin32to16x8:
                           fn = (HWord)h_generic_calc_NarrowBin32to16x8;
                           goto do_SseAssistedBinary;
      do_SseAssistedBinary: {
         /* RRRufff!  RRRufff code is what we're generating here.  Oh
            well. */
         vassert(fn != 0);
         HReg dst = newVRegV(env);
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg argp = newVRegI(env);
         /* subq $112, %rsp         -- make a space*/
         sub_from_rsp(env, 112);
         /* leaq 48(%rsp), %r_argp  -- point into it */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(48, hregAMD64_RSP()),
                                        argp));
         /* andq $-16, %r_argp      -- 16-align the pointer */
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                         AMD64RMI_Imm( ~(UInt)15 ), 
                                         argp));
         /* Prepare 3 arg regs:
            leaq 0(%r_argp), %rdi
            leaq 16(%r_argp), %rsi
            leaq 32(%r_argp), %rdx
         */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, argp),
                                        hregAMD64_RDI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(16, argp),
                                        hregAMD64_RSI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(32, argp),
                                        hregAMD64_RDX()));
         /* Store the two args, at (%rsi) and (%rdx):
            movupd  %argL, 0(%rsi)
            movupd  %argR, 0(%rdx)
         */
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argL,
                                          AMD64AMode_IR(0, hregAMD64_RSI())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argR,
                                          AMD64AMode_IR(0, hregAMD64_RDX())));
         /* call the helper */
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn,
                                        3, mk_RetLoc_simple(RLPri_None) ));
         /* fetch the result from memory, using %r_argp, which the
            register allocator will keep alive across the call. */
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dst,
                                          AMD64AMode_IR(0, argp)));
         /* and finally, clear the space */
         add_to_rsp(env, 112);
         return dst;
      }

      case Iop_SarN64x2: fn = (HWord)h_generic_calc_SarN64x2;
                         goto do_SseAssistedVectorAndScalar;
      case Iop_SarN8x16: fn = (HWord)h_generic_calc_SarN8x16;
                         goto do_SseAssistedVectorAndScalar;
      do_SseAssistedVectorAndScalar: {
         /* RRRufff!  RRRufff code is what we're generating here.  Oh
            well. */
         vassert(fn != 0);
         HReg dst = newVRegV(env);
         HReg argL = iselVecExpr(env, e->Iex.Binop.arg1);
         HReg argR = iselIntExpr_R(env, e->Iex.Binop.arg2);
         HReg argp = newVRegI(env);
         /* subq $112, %rsp         -- make a space*/
         sub_from_rsp(env, 112);
         /* leaq 48(%rsp), %r_argp  -- point into it */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(48, hregAMD64_RSP()),
                                        argp));
         /* andq $-16, %r_argp      -- 16-align the pointer */
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                         AMD64RMI_Imm( ~(UInt)15 ), 
                                         argp));
         /* Prepare 2 vector arg regs:
            leaq 0(%r_argp), %rdi
            leaq 16(%r_argp), %rsi
         */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, argp),
                                        hregAMD64_RDI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(16, argp),
                                        hregAMD64_RSI()));
         /* Store the vector arg, at (%rsi):
            movupd  %argL, 0(%rsi)
         */
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argL,
                                          AMD64AMode_IR(0, hregAMD64_RSI())));
         /* And get the scalar value into rdx */
         addInstr(env, mk_iMOVsd_RR(argR, hregAMD64_RDX()));

         /* call the helper */
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn,
                                        3, mk_RetLoc_simple(RLPri_None) ));
         /* fetch the result from memory, using %r_argp, which the
            register allocator will keep alive across the call. */
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dst,
                                          AMD64AMode_IR(0, argp)));
         /* and finally, clear the space */
         add_to_rsp(env, 112);
         return dst;
      }

      case Iop_I32StoF32x4:
      case Iop_F32toI32Sx4: {
         HReg arg = iselVecExpr(env, e->Iex.Binop.arg2);
         HReg dst = newVRegV(env);
         AMD64SseOp mop
            = e->Iex.Binop.op == Iop_I32StoF32x4 ? Asse_I2F : Asse_F2I;
         set_SSE_rounding_mode(env, e->Iex.Binop.arg1);
         addInstr(env, AMD64Instr_Sse32Fx4(mop, arg, dst));
         set_SSE_rounding_default(env);
         return dst;
      }

      // Half-float vector conversion
      case Iop_F32toF16x8: {
         if (env->hwcaps & VEX_HWCAPS_AMD64_F16C) {
            HReg srcHi, srcLo;
            iselDVecExpr(&srcHi, &srcLo, env, e->Iex.Binop.arg2);
            HReg dstHi = newVRegV(env);
            HReg dstLo = newVRegV(env);
            set_SSE_rounding_mode( env, e->Iex.Binop.arg1 );
            addInstr(env, AMD64Instr_Sse32Fx4(Asse_F32toF16, srcHi, dstHi));
            addInstr(env, AMD64Instr_Sse32Fx4(Asse_F32toF16, srcLo, dstLo));
            set_SSE_rounding_default(env);
            // Now we have the result in dstHi[63:0] and dstLo[63:0], but we
            // need to compact all that into one register.  There's probably a
            // more elegant way to do this, but ..
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dstHi));
            // dstHi is now 127:64 = useful data, 63:0 = zero
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dstLo));
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 64, dstLo));
            // dstLo is now 127:64 = zero, 63:0 = useful data
            addInstr(env, AMD64Instr_SseReRg(Asse_OR, dstHi, dstLo));
            return dstLo;
         }
         break;
      }

      default:
         break;
   } /* switch (e->Iex.Binop.op) */
   } /* if (e->tag == Iex_Binop) */

   if (e->tag == Iex_Triop) {
   IRTriop *triop = e->Iex.Triop.details;
   switch (triop->op) {

      case Iop_Add64Fx2: op = Asse_ADDF; goto do_64Fx2_w_rm;
      case Iop_Sub64Fx2: op = Asse_SUBF; goto do_64Fx2_w_rm;
      case Iop_Mul64Fx2: op = Asse_MULF; goto do_64Fx2_w_rm;
      case Iop_Div64Fx2: op = Asse_DIVF; goto do_64Fx2_w_rm;
      do_64Fx2_w_rm:
      {
         HReg argL = iselVecExpr(env, triop->arg2);
         HReg argR = iselVecExpr(env, triop->arg3);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, AMD64Instr_Sse64Fx2(op, argR, dst));
         return dst;
      }

      case Iop_Add32Fx4: op = Asse_ADDF; goto do_32Fx4_w_rm;
      case Iop_Sub32Fx4: op = Asse_SUBF; goto do_32Fx4_w_rm;
      case Iop_Mul32Fx4: op = Asse_MULF; goto do_32Fx4_w_rm;
      case Iop_Div32Fx4: op = Asse_DIVF; goto do_32Fx4_w_rm;
      do_32Fx4_w_rm:
      {
         HReg argL = iselVecExpr(env, triop->arg2);
         HReg argR = iselVecExpr(env, triop->arg3);
         HReg dst = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argL, dst));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, AMD64Instr_Sse32Fx4(op, argR, dst));
         return dst;
      }

      default:
         break;
   } /* switch (triop->op) */
   } /* if (e->tag == Iex_Triop) */

   if (e->tag == Iex_ITE) { // VFD
      HReg r1  = iselVecExpr(env, e->Iex.ITE.iftrue);
      HReg r0  = iselVecExpr(env, e->Iex.ITE.iffalse);
      HReg dst = newVRegV(env);
      addInstr(env, mk_vMOVsd_RR(r1,dst));
      AMD64CondCode cc = iselCondCode(env, e->Iex.ITE.cond);
      addInstr(env, AMD64Instr_SseCMov(cc ^ 1, r0, dst));
      return dst;
   }

   //vec_fail:
   vex_printf("iselVecExpr (amd64, subarch = %s): can't reduce\n",
              LibVEX_ppVexHwCaps(VexArchAMD64, env->hwcaps));
   ppIRExpr(e);
   vpanic("iselVecExpr_wrk");
}


/*---------------------------------------------------------*/
/*--- ISEL: SIMD (V256) expressions, into 2 XMM regs.    --*/
/*---------------------------------------------------------*/

static void iselDVecExpr ( /*OUT*/HReg* rHi, /*OUT*/HReg* rLo, 
                           ISelEnv* env, const IRExpr* e )
{
   iselDVecExpr_wrk( rHi, rLo, env, e );
#  if 0
   vex_printf("\n"); ppIRExpr(e); vex_printf("\n");
#  endif
   vassert(hregClass(*rHi) == HRcVec128);
   vassert(hregClass(*rLo) == HRcVec128);
   vassert(hregIsVirtual(*rHi));
   vassert(hregIsVirtual(*rLo));
}


/* DO NOT CALL THIS DIRECTLY */
static void iselDVecExpr_wrk ( /*OUT*/HReg* rHi, /*OUT*/HReg* rLo, 
                               ISelEnv* env, const IRExpr* e )
{
   HWord fn = 0; /* address of helper fn, if required */
   vassert(e);
   IRType ty = typeOfIRExpr(env->type_env, e);
   vassert(ty == Ity_V256);
   UInt laneBits = 0;

   AMD64SseOp op = Asse_INVALID;

   /* read 256-bit IRTemp */
   if (e->tag == Iex_RdTmp) {
      lookupIRTempPair( rHi, rLo, env, e->Iex.RdTmp.tmp);
      return;
   }
 
   if (e->tag == Iex_Get) {
      HReg        vHi  = newVRegV(env);
      HReg        vLo  = newVRegV(env);
      HReg        rbp  = hregAMD64_RBP();
      AMD64AMode* am0  = AMD64AMode_IR(e->Iex.Get.offset + 0,  rbp);
      AMD64AMode* am16 = AMD64AMode_IR(e->Iex.Get.offset + 16, rbp);
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, vLo, am0));
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, vHi, am16));
      *rHi = vHi;
      *rLo = vLo;
      return;
   }

   if (e->tag == Iex_Load) {
      HReg        vHi  = newVRegV(env);
      HReg        vLo  = newVRegV(env);
      HReg        rA   = iselIntExpr_R(env, e->Iex.Load.addr);
      AMD64AMode* am0  = AMD64AMode_IR(0,  rA);
      AMD64AMode* am16 = AMD64AMode_IR(16, rA);
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, vLo, am0));
      addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, vHi, am16));
      *rHi = vHi;
      *rLo = vLo;
      return;
   }

   if (e->tag == Iex_Const) {
      vassert(e->Iex.Const.con->tag == Ico_V256);
      switch (e->Iex.Const.con->Ico.V256) {
         case 0x00000000: {
            HReg vHi = generate_zeroes_V128(env);
            HReg vLo = newVRegV(env);
            addInstr(env, mk_vMOVsd_RR(vHi, vLo));
            *rHi = vHi;
            *rLo = vLo;
            return;
         }
         default:
            break; /* give up.   Until such time as is necessary. */
      }
   }

   if (e->tag == Iex_Unop) {
   switch (e->Iex.Unop.op) {

      case Iop_NotV256: {
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Unop.arg);
         *rHi = do_sse_NotV128(env, argHi);
         *rLo = do_sse_NotV128(env, argLo);
         return;
      }

      case Iop_RecipEst32Fx8: op = Asse_RCPF;   goto do_32Fx8_unary;
      case Iop_Sqrt32Fx8:     op = Asse_SQRTF;  goto do_32Fx8_unary;
      case Iop_RSqrtEst32Fx8: op = Asse_RSQRTF; goto do_32Fx8_unary;
      do_32Fx8_unary:
      {
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Unop.arg);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, AMD64Instr_Sse32Fx4(op, argHi, dstHi));
         addInstr(env, AMD64Instr_Sse32Fx4(op, argLo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_Sqrt64Fx4:  op = Asse_SQRTF;  goto do_64Fx4_unary;
      do_64Fx4_unary:
      {
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Unop.arg);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, AMD64Instr_Sse64Fx2(op, argHi, dstHi));
         addInstr(env, AMD64Instr_Sse64Fx2(op, argLo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_CmpNEZ64x4: {
         /* We can use SSE2 instructions for this. */
         /* Same scheme as Iop_CmpNEZ64x2, except twice as wide
            (obviously).  See comment on Iop_CmpNEZ64x2 for
            explanation of what's going on here. */
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Unop.arg);
         HReg tmpHi  = generate_zeroes_V128(env);
         HReg tmpLo  = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(tmpHi, tmpLo));
         HReg dstHi  = newVRegV(env);
         HReg dstLo  = newVRegV(env);
         addInstr(env, AMD64Instr_SseReRg(Asse_CMPEQ32, argHi, tmpHi));
         addInstr(env, AMD64Instr_SseReRg(Asse_CMPEQ32, argLo, tmpLo));
         tmpHi = do_sse_NotV128(env, tmpHi);
         tmpLo = do_sse_NotV128(env, tmpLo);
         addInstr(env, AMD64Instr_SseShuf(0xB1, tmpHi, dstHi));
         addInstr(env, AMD64Instr_SseShuf(0xB1, tmpLo, dstLo));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmpHi, dstHi));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmpLo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_CmpNEZ32x8: op = Asse_CMPEQ32; goto do_CmpNEZ_vector;
      case Iop_CmpNEZ16x16: op = Asse_CMPEQ16; goto do_CmpNEZ_vector;
      case Iop_CmpNEZ8x32: op = Asse_CMPEQ8;  goto do_CmpNEZ_vector;
      do_CmpNEZ_vector:
      {
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Unop.arg);
         HReg tmpHi = newVRegV(env);
         HReg tmpLo = newVRegV(env);
         HReg zero  = generate_zeroes_V128(env);
         HReg dstHi, dstLo;
         addInstr(env, mk_vMOVsd_RR(argHi, tmpHi));
         addInstr(env, mk_vMOVsd_RR(argLo, tmpLo));
         addInstr(env, AMD64Instr_SseReRg(op, zero, tmpHi));
         addInstr(env, AMD64Instr_SseReRg(op, zero, tmpLo));
         dstHi = do_sse_NotV128(env, tmpHi);
         dstLo = do_sse_NotV128(env, tmpLo);
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_F16toF32x8: {
         if (env->hwcaps & VEX_HWCAPS_AMD64_F16C) {
            HReg src     = iselVecExpr(env, e->Iex.Unop.arg);
            HReg srcCopy = newVRegV(env);
            HReg dstHi   = newVRegV(env);
            HReg dstLo   = newVRegV(env);
            // Copy src, since we'll need to modify it.
            addInstr(env, mk_vMOVsd_RR(src, srcCopy));
            addInstr(env, AMD64Instr_Sse32Fx4(Asse_F16toF32, srcCopy, dstLo));
            addInstr(env, AMD64Instr_SseShiftN(Asse_SHR128, 64, srcCopy));
            addInstr(env, AMD64Instr_Sse32Fx4(Asse_F16toF32, srcCopy, dstHi));
            *rHi = dstHi;
            *rLo = dstLo;
            return;
         }
         break;
      }

      default:
         break;
   } /* switch (e->Iex.Unop.op) */
   } /* if (e->tag == Iex_Unop) */

   if (e->tag == Iex_Binop) {
   switch (e->Iex.Binop.op) {

      case Iop_Max64Fx4:   op = Asse_MAXF;   goto do_64Fx4;
      case Iop_Min64Fx4:   op = Asse_MINF;   goto do_64Fx4;
      do_64Fx4:
      {
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, e->Iex.Binop.arg1);
         iselDVecExpr(&argRhi, &argRlo, env, e->Iex.Binop.arg2);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argLhi, dstHi));
         addInstr(env, mk_vMOVsd_RR(argLlo, dstLo));
         addInstr(env, AMD64Instr_Sse64Fx2(op, argRhi, dstHi));
         addInstr(env, AMD64Instr_Sse64Fx2(op, argRlo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_Max32Fx8:   op = Asse_MAXF;   goto do_32Fx8;
      case Iop_Min32Fx8:   op = Asse_MINF;   goto do_32Fx8;
      do_32Fx8:
      {
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, e->Iex.Binop.arg1);
         iselDVecExpr(&argRhi, &argRlo, env, e->Iex.Binop.arg2);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argLhi, dstHi));
         addInstr(env, mk_vMOVsd_RR(argLlo, dstLo));
         addInstr(env, AMD64Instr_Sse32Fx4(op, argRhi, dstHi));
         addInstr(env, AMD64Instr_Sse32Fx4(op, argRlo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_AndV256:    op = Asse_AND;      goto do_SseReRg;
      case Iop_OrV256:     op = Asse_OR;       goto do_SseReRg;
      case Iop_XorV256:    op = Asse_XOR;      goto do_SseReRg;
      case Iop_Add8x32:    op = Asse_ADD8;     goto do_SseReRg;
      case Iop_Add16x16:   op = Asse_ADD16;    goto do_SseReRg;
      case Iop_Add32x8:    op = Asse_ADD32;    goto do_SseReRg;
      case Iop_Add64x4:    op = Asse_ADD64;    goto do_SseReRg;
      case Iop_QAdd8Sx32:  op = Asse_QADD8S;   goto do_SseReRg;
      case Iop_QAdd16Sx16: op = Asse_QADD16S;  goto do_SseReRg;
      case Iop_QAdd8Ux32:  op = Asse_QADD8U;   goto do_SseReRg;
      case Iop_QAdd16Ux16: op = Asse_QADD16U;  goto do_SseReRg;
      case Iop_Avg8Ux32:   op = Asse_AVG8U;    goto do_SseReRg;
      case Iop_Avg16Ux16:  op = Asse_AVG16U;   goto do_SseReRg;
      case Iop_CmpEQ8x32:  op = Asse_CMPEQ8;   goto do_SseReRg;
      case Iop_CmpEQ16x16: op = Asse_CMPEQ16;  goto do_SseReRg;
      case Iop_CmpEQ32x8:  op = Asse_CMPEQ32;  goto do_SseReRg;
      case Iop_CmpGT8Sx32: op = Asse_CMPGT8S;  goto do_SseReRg;
      case Iop_CmpGT16Sx16: op = Asse_CMPGT16S; goto do_SseReRg;
      case Iop_CmpGT32Sx8: op = Asse_CMPGT32S; goto do_SseReRg;
      case Iop_Max16Sx16:  op = Asse_MAX16S;   goto do_SseReRg;
      case Iop_Max8Ux32:   op = Asse_MAX8U;    goto do_SseReRg;
      case Iop_Min16Sx16:  op = Asse_MIN16S;   goto do_SseReRg;
      case Iop_Min8Ux32:   op = Asse_MIN8U;    goto do_SseReRg;
      case Iop_MulHi16Ux16: op = Asse_MULHI16U; goto do_SseReRg;
      case Iop_MulHi16Sx16: op = Asse_MULHI16S; goto do_SseReRg;
      case Iop_Mul16x16:   op = Asse_MUL16;    goto do_SseReRg;
      case Iop_Sub8x32:    op = Asse_SUB8;     goto do_SseReRg;
      case Iop_Sub16x16:   op = Asse_SUB16;    goto do_SseReRg;
      case Iop_Sub32x8:    op = Asse_SUB32;    goto do_SseReRg;
      case Iop_Sub64x4:    op = Asse_SUB64;    goto do_SseReRg;
      case Iop_QSub8Sx32:  op = Asse_QSUB8S;   goto do_SseReRg;
      case Iop_QSub16Sx16: op = Asse_QSUB16S;  goto do_SseReRg;
      case Iop_QSub8Ux32:  op = Asse_QSUB8U;   goto do_SseReRg;
      case Iop_QSub16Ux16: op = Asse_QSUB16U;  goto do_SseReRg;
      do_SseReRg:
      {
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, e->Iex.Binop.arg1);
         iselDVecExpr(&argRhi, &argRlo, env, e->Iex.Binop.arg2);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argLhi, dstHi));
         addInstr(env, mk_vMOVsd_RR(argLlo, dstLo));
         addInstr(env, AMD64Instr_SseReRg(op, argRhi, dstHi));
         addInstr(env, AMD64Instr_SseReRg(op, argRlo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_ShlN16x16: laneBits = 16; op = Asse_SHL16; goto do_SseShift;
      case Iop_ShlN32x8:  laneBits = 32; op = Asse_SHL32; goto do_SseShift;
      case Iop_ShlN64x4:  laneBits = 64; op = Asse_SHL64; goto do_SseShift;
      case Iop_SarN16x16: laneBits = 16; op = Asse_SAR16; goto do_SseShift;
      case Iop_SarN32x8:  laneBits = 32; op = Asse_SAR32; goto do_SseShift;
      case Iop_ShrN16x16: laneBits = 16; op = Asse_SHR16; goto do_SseShift;
      case Iop_ShrN32x8:  laneBits = 32; op = Asse_SHR32; goto do_SseShift;
      case Iop_ShrN64x4:  laneBits = 64; op = Asse_SHR64; goto do_SseShift;
      do_SseShift: {
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         HReg gregHi, gregLo;
         iselDVecExpr(&gregHi, &gregLo, env, e->Iex.Binop.arg1);
         /* If it's a shift by an in-range immediate, generate two single
            instructions. */
         if (e->Iex.Binop.arg2->tag == Iex_Const) {
            IRConst* c = e->Iex.Binop.arg2->Iex.Const.con;
            vassert(c->tag == Ico_U8);
            UInt shift = c->Ico.U8;
            if (shift < laneBits) {
               addInstr(env, mk_vMOVsd_RR(gregHi, dstHi));
               addInstr(env, AMD64Instr_SseShiftN(op, shift, dstHi));
               addInstr(env, mk_vMOVsd_RR(gregLo, dstLo));
               addInstr(env, AMD64Instr_SseShiftN(op, shift, dstLo));
               *rHi = dstHi;
               *rLo = dstLo;
               return;
            }
         }
         /* Otherwise we have to do it the longwinded way. */
         AMD64RMI*   rmi   = iselIntExpr_RMI(env, e->Iex.Binop.arg2);
         AMD64AMode* rsp0  = AMD64AMode_IR(0, hregAMD64_RSP());
         HReg        ereg  = newVRegV(env);
         addInstr(env, AMD64Instr_Push(AMD64RMI_Imm(0)));
         addInstr(env, AMD64Instr_Push(rmi));
         addInstr(env, AMD64Instr_SseLdSt(True/*load*/, 16, ereg, rsp0));
         addInstr(env, mk_vMOVsd_RR(gregHi, dstHi));
         addInstr(env, AMD64Instr_SseReRg(op, ereg, dstHi));
         addInstr(env, mk_vMOVsd_RR(gregLo, dstLo));
         addInstr(env, AMD64Instr_SseReRg(op, ereg, dstLo));
         add_to_rsp(env, 16);
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_V128HLtoV256: {
         // Curiously, there doesn't seem to be any benefit to be had here by
         // checking whether arg1 and arg2 are the same, in the style of how
         // (eg) 64HLtoV128 is handled elsewhere in this file.
         *rHi = iselVecExpr(env, e->Iex.Binop.arg1);
         *rLo = iselVecExpr(env, e->Iex.Binop.arg2);
         return;
      }

      case Iop_Mul32x8:    fn = (HWord)h_generic_calc_Mul32x4;
                           goto do_SseAssistedBinary;
      case Iop_Max32Sx8:   fn = (HWord)h_generic_calc_Max32Sx4;
                           goto do_SseAssistedBinary;
      case Iop_Min32Sx8:   fn = (HWord)h_generic_calc_Min32Sx4;
                           goto do_SseAssistedBinary;
      case Iop_Max32Ux8:   fn = (HWord)h_generic_calc_Max32Ux4;
                           goto do_SseAssistedBinary;
      case Iop_Min32Ux8:   fn = (HWord)h_generic_calc_Min32Ux4;
                           goto do_SseAssistedBinary;
      case Iop_Max16Ux16:  fn = (HWord)h_generic_calc_Max16Ux8;
                           goto do_SseAssistedBinary;
      case Iop_Min16Ux16:  fn = (HWord)h_generic_calc_Min16Ux8;
                           goto do_SseAssistedBinary;
      case Iop_Max8Sx32:   fn = (HWord)h_generic_calc_Max8Sx16;
                           goto do_SseAssistedBinary;
      case Iop_Min8Sx32:   fn = (HWord)h_generic_calc_Min8Sx16;
                           goto do_SseAssistedBinary;
      case Iop_CmpEQ64x4:  fn = (HWord)h_generic_calc_CmpEQ64x2;
                           goto do_SseAssistedBinary;
      case Iop_CmpGT64Sx4: fn = (HWord)h_generic_calc_CmpGT64Sx2;
                           goto do_SseAssistedBinary;
      do_SseAssistedBinary: {
         /* RRRufff!  RRRufff code is what we're generating here.  Oh
            well. */
         vassert(fn != 0);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, e->Iex.Binop.arg1);
         iselDVecExpr(&argRhi, &argRlo, env, e->Iex.Binop.arg2);
         HReg argp = newVRegI(env);
         /* subq $160, %rsp         -- make a space*/
         sub_from_rsp(env, 160);
         /* leaq 48(%rsp), %r_argp  -- point into it */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(48, hregAMD64_RSP()),
                                        argp));
         /* andq $-16, %r_argp      -- 16-align the pointer */
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                         AMD64RMI_Imm( ~(UInt)15 ),
                                         argp));
         /* Prepare 3 arg regs:
            leaq 0(%r_argp), %rdi
            leaq 16(%r_argp), %rsi
            leaq 32(%r_argp), %rdx
         */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, argp),
                                        hregAMD64_RDI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(16, argp),
                                        hregAMD64_RSI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(32, argp),
                                        hregAMD64_RDX()));
         /* Store the two high args, at (%rsi) and (%rdx):
            movupd  %argLhi, 0(%rsi)
            movupd  %argRhi, 0(%rdx)
         */
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argLhi,
                                          AMD64AMode_IR(0, hregAMD64_RSI())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argRhi,
                                          AMD64AMode_IR(0, hregAMD64_RDX())));
         /* Store the two low args, at 48(%rsi) and 48(%rdx):
            movupd  %argLlo, 48(%rsi)
            movupd  %argRlo, 48(%rdx)
         */
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argLlo,
                                          AMD64AMode_IR(48, hregAMD64_RSI())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argRlo,
                                          AMD64AMode_IR(48, hregAMD64_RDX())));
         /* call the helper */
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn, 3,
                                        mk_RetLoc_simple(RLPri_None) ));
         /* Prepare 3 arg regs:
            leaq 48(%r_argp), %rdi
            leaq 64(%r_argp), %rsi
            leaq 80(%r_argp), %rdx
         */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(48, argp),
                                        hregAMD64_RDI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(64, argp),
                                        hregAMD64_RSI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(80, argp),
                                        hregAMD64_RDX()));
         /* call the helper */
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn, 3,
                                        mk_RetLoc_simple(RLPri_None) ));
         /* fetch the result from memory, using %r_argp, which the
            register allocator will keep alive across the call. */
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dstHi,
                                          AMD64AMode_IR(0, argp)));
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dstLo,
                                          AMD64AMode_IR(48, argp)));
         /* and finally, clear the space */
         add_to_rsp(env, 160);
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_Perm32x8:   fn = (HWord)h_generic_calc_Perm32x8;
                           goto do_SseAssistedBinary256;
      do_SseAssistedBinary256: {
         /* RRRufff!  RRRufff code is what we're generating here.  Oh
            well. */
         vassert(fn != 0);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, e->Iex.Binop.arg1);
         iselDVecExpr(&argRhi, &argRlo, env, e->Iex.Binop.arg2);
         HReg argp = newVRegI(env);
         /* subq $160, %rsp         -- make a space*/
         sub_from_rsp(env, 160);
         /* leaq 48(%rsp), %r_argp  -- point into it */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(48, hregAMD64_RSP()),
                                        argp));
         /* andq $-16, %r_argp      -- 16-align the pointer */
         addInstr(env, AMD64Instr_Alu64R(Aalu_AND,
                                         AMD64RMI_Imm( ~(UInt)15 ),
                                         argp));
         /* Prepare 3 arg regs:
            leaq 0(%r_argp), %rdi
            leaq 32(%r_argp), %rsi
            leaq 64(%r_argp), %rdx
         */
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(0, argp),
                                        hregAMD64_RDI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(32, argp),
                                        hregAMD64_RSI()));
         addInstr(env, AMD64Instr_Lea64(AMD64AMode_IR(64, argp),
                                        hregAMD64_RDX()));
         /* Store the two args, at (%rsi) and (%rdx):
            movupd  %argLlo, 0(%rsi)
            movupd  %argLhi, 16(%rsi)
            movupd  %argRlo, 0(%rdx)
            movupd  %argRhi, 16(%rdx)
         */
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argLlo,
                                          AMD64AMode_IR(0, hregAMD64_RSI())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argLhi,
                                          AMD64AMode_IR(16, hregAMD64_RSI())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argRlo,
                                          AMD64AMode_IR(0, hregAMD64_RDX())));
         addInstr(env, AMD64Instr_SseLdSt(False/*!isLoad*/, 16, argRhi,
                                          AMD64AMode_IR(16, hregAMD64_RDX())));
         /* call the helper */
         addInstr(env, AMD64Instr_Call( Acc_ALWAYS, (ULong)fn, 3,
                                        mk_RetLoc_simple(RLPri_None) ));
         /* fetch the result from memory, using %r_argp, which the
            register allocator will keep alive across the call. */
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dstLo,
                                          AMD64AMode_IR(0, argp)));
         addInstr(env, AMD64Instr_SseLdSt(True/*isLoad*/, 16, dstHi,
                                          AMD64AMode_IR(16, argp)));
         /* and finally, clear the space */
         add_to_rsp(env, 160);
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_I32StoF32x8:
      case Iop_F32toI32Sx8: {
         HReg argHi, argLo;
         iselDVecExpr(&argHi, &argLo, env, e->Iex.Binop.arg2);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         AMD64SseOp mop
            = e->Iex.Binop.op == Iop_I32StoF32x8 ? Asse_I2F : Asse_F2I;
         set_SSE_rounding_mode(env, e->Iex.Binop.arg1);
         addInstr(env, AMD64Instr_Sse32Fx4(mop, argHi, dstHi));
         addInstr(env, AMD64Instr_Sse32Fx4(mop, argLo, dstLo));
         set_SSE_rounding_default(env);
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      default:
         break;
   } /* switch (e->Iex.Binop.op) */
   } /* if (e->tag == Iex_Binop) */

   if (e->tag == Iex_Triop) {
   IRTriop *triop = e->Iex.Triop.details;
   switch (triop->op) {

      case Iop_Add64Fx4: op = Asse_ADDF; goto do_64Fx4_w_rm;
      case Iop_Sub64Fx4: op = Asse_SUBF; goto do_64Fx4_w_rm;
      case Iop_Mul64Fx4: op = Asse_MULF; goto do_64Fx4_w_rm;
      case Iop_Div64Fx4: op = Asse_DIVF; goto do_64Fx4_w_rm;
      do_64Fx4_w_rm:
      {
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, triop->arg2);
         iselDVecExpr(&argRhi, &argRlo, env, triop->arg3);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argLhi, dstHi));
         addInstr(env, mk_vMOVsd_RR(argLlo, dstLo));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, AMD64Instr_Sse64Fx2(op, argRhi, dstHi));
         addInstr(env, AMD64Instr_Sse64Fx2(op, argRlo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      case Iop_Add32Fx8: op = Asse_ADDF; goto do_32Fx8_w_rm;
      case Iop_Sub32Fx8: op = Asse_SUBF; goto do_32Fx8_w_rm;
      case Iop_Mul32Fx8: op = Asse_MULF; goto do_32Fx8_w_rm;
      case Iop_Div32Fx8: op = Asse_DIVF; goto do_32Fx8_w_rm;
      do_32Fx8_w_rm:
      {
         HReg argLhi, argLlo, argRhi, argRlo;
         iselDVecExpr(&argLhi, &argLlo, env, triop->arg2);
         iselDVecExpr(&argRhi, &argRlo, env, triop->arg3);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, mk_vMOVsd_RR(argLhi, dstHi));
         addInstr(env, mk_vMOVsd_RR(argLlo, dstLo));
         /* XXXROUNDINGFIXME */
         /* set roundingmode here */
         addInstr(env, AMD64Instr_Sse32Fx4(op, argRhi, dstHi));
         addInstr(env, AMD64Instr_Sse32Fx4(op, argRlo, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
         return;
      }

      default:
         break;
   } /* switch (triop->op) */
   } /* if (e->tag == Iex_Triop) */


   if (e->tag == Iex_Qop && e->Iex.Qop.details->op == Iop_64x4toV256) {
      const IRExpr* arg1 = e->Iex.Qop.details->arg1;
      const IRExpr* arg2 = e->Iex.Qop.details->arg2;
      const IRExpr* arg3 = e->Iex.Qop.details->arg3;
      const IRExpr* arg4 = e->Iex.Qop.details->arg4;
      // If the args are trivially the same (tmp or const), use the same
      // source register for all four, and only one movq since those are
      // (relatively) expensive.
      if (areAtomsAndEqual(arg1, arg2)
          && areAtomsAndEqual(arg1, arg3) && areAtomsAndEqual(arg1, arg4)) {
         HReg q3 = iselIntExpr_R(env, e->Iex.Qop.details->arg1);
         HReg tmp = newVRegV(env);
         HReg dst = newVRegV(env);
         addInstr(env, AMD64Instr_SseMOVQ(q3, dst, True/*toXMM*/));
         addInstr(env, mk_vMOVsd_RR(dst, tmp));
         addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dst));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dst));
         *rHi = dst;
         *rLo = dst;
      } else {
         /* arg1 is the most significant (Q3), arg4 the least (Q0) */
         HReg q3 = iselIntExpr_R(env, arg1);
         HReg q2 = iselIntExpr_R(env, arg2);
         HReg q1 = iselIntExpr_R(env, arg3);
         HReg q0 = iselIntExpr_R(env, arg4);
         HReg tmp = newVRegV(env);
         HReg dstHi = newVRegV(env);
         HReg dstLo = newVRegV(env);
         addInstr(env, AMD64Instr_SseMOVQ(q3, dstHi, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dstHi));
         addInstr(env, AMD64Instr_SseMOVQ(q2, tmp, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dstHi));
         addInstr(env, AMD64Instr_SseMOVQ(q1, dstLo, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseShiftN(Asse_SHL128, 64, dstLo));
         addInstr(env, AMD64Instr_SseMOVQ(q0, tmp, True/*toXMM*/));
         addInstr(env, AMD64Instr_SseReRg(Asse_OR, tmp, dstLo));
         *rHi = dstHi;
         *rLo = dstLo;
      }
      return;
   }

   if (e->tag == Iex_ITE) {
      HReg r1Hi, r1Lo, r0Hi, r0Lo;
      iselDVecExpr(&r1Hi, &r1Lo, env, e->Iex.ITE.iftrue);
      iselDVecExpr(&r0Hi, &r0Lo, env, e->Iex.ITE.iffalse);
      HReg dstHi = newVRegV(env);
      HReg dstLo = newVRegV(env);
      addInstr(env, mk_vMOVsd_RR(r1Hi,dstHi));
      addInstr(env, mk_vMOVsd_RR(r1Lo,dstLo));
      AMD64CondCode cc = iselCondCode(env, e->Iex.ITE.cond);
      addInstr(env, AMD64Instr_SseCMov(cc ^ 1, r0Hi, dstHi));
      addInstr(env, AMD64Instr_SseCMov(cc ^ 1, r0Lo, dstLo));
      *rHi = dstHi;
      *rLo = dstLo;
      return;
   }

   //avx_fail:
   vex_printf("iselDVecExpr (amd64, subarch = %s): can't reduce\n",
              LibVEX_ppVexHwCaps(VexArchAMD64, env->hwcaps));
   ppIRExpr(e);
   vpanic("iselDVecExpr_wrk");
}


/*---------------------------------------------------------*/
/*--- ISEL: Statements                                  ---*/
/*---------------------------------------------------------*/

static void iselStmt ( ISelEnv* env, IRStmt* stmt )
{
   if (vex_traceflags & VEX_TRACE_VCODE) {
      vex_printf("\n-- ");
      ppIRStmt(stmt);
      vex_printf("\n");
   }

   switch (stmt->tag) {

   /* --------- LOADG (guarded load) --------- */
   case Ist_LoadG: {
      IRLoadG* lg = stmt->Ist.LoadG.details;
      if (lg->end != Iend_LE)
         goto stmt_fail;

      UChar szB = 0; /* invalid */
      switch (lg->cvt) {
         case ILGop_Ident32:   szB = 4;  break;
         case ILGop_Ident64:   szB = 8;  break;
         case ILGop_IdentV128: szB = 16; break;
         default: break;
      }
      if (szB == 0)
         goto stmt_fail;

      AMD64AMode* amAddr
         = iselIntExpr_AMode(env, lg->addr);
      HReg rAlt
         = szB == 16 ? iselVecExpr(env, lg->alt)
                     : iselIntExpr_R(env, lg->alt);
      HReg rDst
         = lookupIRTemp(env, lg->dst);

      /* Get the alt value into the dst.  We'll do a conditional load
         which overwrites it -- or not -- with loaded data. */
      if (szB == 16) {
         addInstr(env, mk_vMOVsd_RR(rAlt, rDst));
      } else {
         addInstr(env, mk_iMOVsd_RR(rAlt, rDst));
      }
      AMD64CondCode cc = iselCondCode(env, lg->guard);
      if (szB == 16) {
         addInstr(env, AMD64Instr_SseCLoad(cc, amAddr, rDst));
      } else {
         addInstr(env, AMD64Instr_CLoad(cc, szB, amAddr, rDst));
      }
      return;
   }

   /* --------- STOREG (guarded store) --------- */
   case Ist_StoreG: {
      IRStoreG* sg = stmt->Ist.StoreG.details;
      if (sg->end != Iend_LE)
         goto stmt_fail;

      UChar szB = 0; /* invalid */
      switch (typeOfIRExpr(env->type_env, sg->data)) {
         case Ity_I32:  szB = 4; break;
         case Ity_I64:  szB = 8; break;
         case Ity_V128: szB = 16; break;
         default: break;
      }
      if (szB == 0)
         goto stmt_fail;

      AMD64AMode* amAddr
         = iselIntExpr_AMode(env, sg->addr);
      HReg rSrc
         = szB == 16 ? iselVecExpr(env, sg->data)
                     : iselIntExpr_R(env, sg->data);
      AMD64CondCode cc
         = iselCondCode(env, sg->guard);
      if (szB == 16) {
         addInstr(env, AMD64Instr_SseCStore(cc, rSrc, amAddr));
      } else {
         addInstr(env, AMD64Instr_CStore(cc, szB, rSrc, amAddr));
      }
      return;
   }

   /* --------- STORE --------- */
   case Ist_Store: {
      IRType    tya   = typeOfIRExpr(env->type_env, stmt->Ist.Store.addr);
      IRType    tyd   = typeOfIRExpr(env->type_env, stmt->Ist.Store.data);
      IREndness end   = stmt->Ist.Store.end;

      if (tya != Ity_I64 || end != Iend_LE)
         goto stmt_fail;

      if (tyd == Ity_I64) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.Store.addr);
         AMD64RI* ri = iselIntExpr_RI(env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_Alu64M(Aalu_MOV,ri,am));
         return;
      }
      if (tyd == Ity_I8 || tyd == Ity_I16 || tyd == Ity_I32) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.Store.addr);
         HReg r = iselIntExpr_R(env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_Store(
                          toUChar(tyd==Ity_I8 ? 1 : (tyd==Ity_I16 ? 2 : 4)),
                          r,am));
         return;
      }
      if (tyd == Ity_F64) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.Store.addr);
         HReg r = iselDblExpr(env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 8, r, am));
         return;
      }
      if (tyd == Ity_F32) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.Store.addr);
         HReg r = iselFltExpr(env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 4, r, am));
         return;
      }
      if (tyd == Ity_V128) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.Store.addr);
         HReg r = iselVecExpr(env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, r, am));
         return;
      }
      if (tyd == Ity_V256) {
         HReg        rA   = iselIntExpr_R(env, stmt->Ist.Store.addr);
         AMD64AMode* am0  = AMD64AMode_IR(0,  rA);
         AMD64AMode* am16 = AMD64AMode_IR(16, rA);
         HReg vHi, vLo;
         iselDVecExpr(&vHi, &vLo, env, stmt->Ist.Store.data);
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vLo, am0));
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vHi, am16));
         return;
      }
      break;
   }

   /* --------- PUT --------- */
   case Ist_Put: {
      IRType ty = typeOfIRExpr(env->type_env, stmt->Ist.Put.data);
      if (ty == Ity_I64) {
         /* We're going to write to memory, so compute the RHS into an
            AMD64RI. */
         AMD64RI* ri = iselIntExpr_RI(env, stmt->Ist.Put.data);
         addInstr(env,
                  AMD64Instr_Alu64M(
                     Aalu_MOV,
                     ri,
                     AMD64AMode_IR(stmt->Ist.Put.offset,
                                   hregAMD64_RBP())
                 ));
         return;
      }
      if (ty == Ity_I8 || ty == Ity_I16 || ty == Ity_I32) {
         HReg r = iselIntExpr_R(env, stmt->Ist.Put.data);
         addInstr(env, AMD64Instr_Store(
                          toUChar(ty==Ity_I8 ? 1 : (ty==Ity_I16 ? 2 : 4)),
                          r,
                          AMD64AMode_IR(stmt->Ist.Put.offset,
                                        hregAMD64_RBP())));
         return;
      }
      if (ty == Ity_F32) {
         HReg f32 = iselFltExpr(env, stmt->Ist.Put.data);
         AMD64AMode* am = AMD64AMode_IR(stmt->Ist.Put.offset, hregAMD64_RBP());
         set_SSE_rounding_default(env); /* paranoia */
         addInstr(env, AMD64Instr_SseLdSt( False/*store*/, 4, f32, am ));
         return;
      }
      if (ty == Ity_F64) {
         HReg f64 = iselDblExpr(env, stmt->Ist.Put.data);
         AMD64AMode* am = AMD64AMode_IR( stmt->Ist.Put.offset, 
                                         hregAMD64_RBP() );
         addInstr(env, AMD64Instr_SseLdSt( False/*store*/, 8, f64, am ));
         return;
      }
      if (ty == Ity_V128) {
         HReg        vec = iselVecExpr(env, stmt->Ist.Put.data);
         AMD64AMode* am  = AMD64AMode_IR(stmt->Ist.Put.offset, 
                                         hregAMD64_RBP());
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vec, am));
         return;
      }
      if (ty == Ity_V256) {
         HReg vHi, vLo;
         iselDVecExpr(&vHi, &vLo, env, stmt->Ist.Put.data);
         HReg        rbp  = hregAMD64_RBP();
         AMD64AMode* am0  = AMD64AMode_IR(stmt->Ist.Put.offset + 0,  rbp);
         AMD64AMode* am16 = AMD64AMode_IR(stmt->Ist.Put.offset + 16, rbp);
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vLo, am0));
         addInstr(env, AMD64Instr_SseLdSt(False/*store*/, 16, vHi, am16));
         return;
      }
      break;
   }

   /* --------- Indexed PUT --------- */
   case Ist_PutI: {
      IRPutI *puti = stmt->Ist.PutI.details;

      AMD64AMode* am 
         = genGuestArrayOffset(
              env, puti->descr, 
                   puti->ix, puti->bias );

      IRType ty = typeOfIRExpr(env->type_env, puti->data);
      if (ty == Ity_F64) {
         HReg val = iselDblExpr(env, puti->data);
         addInstr(env, AMD64Instr_SseLdSt( False/*store*/, 8, val, am ));
         return;
      }
      if (ty == Ity_I8) {
         HReg r = iselIntExpr_R(env, puti->data);
         addInstr(env, AMD64Instr_Store( 1, r, am ));
         return;
      }
      if (ty == Ity_I64) {
         AMD64RI* ri = iselIntExpr_RI(env, puti->data);
         addInstr(env, AMD64Instr_Alu64M( Aalu_MOV, ri, am ));
         return;
      }
      break;
   }

   /* --------- TMP --------- */
   case Ist_WrTmp: {
      IRTemp tmp = stmt->Ist.WrTmp.tmp;
      IRType ty = typeOfIRTemp(env->type_env, tmp);

      /* optimisation: if stmt->Ist.WrTmp.data is Add64(..,..),
         compute it into an AMode and then use LEA.  This usually
         produces fewer instructions, often because (for memcheck
         created IR) we get t = address-expression, (t is later used
         twice) and so doing this naturally turns address-expression
         back into an AMD64 amode. */
      if (ty == Ity_I64 
          && stmt->Ist.WrTmp.data->tag == Iex_Binop
          && stmt->Ist.WrTmp.data->Iex.Binop.op == Iop_Add64) {
         AMD64AMode* am = iselIntExpr_AMode(env, stmt->Ist.WrTmp.data);
         HReg dst = lookupIRTemp(env, tmp);
         if (am->tag == Aam_IR && am->Aam.IR.imm == 0) {
            /* Hmm, iselIntExpr_AMode wimped out and just computed the
               value into a register.  Just emit a normal reg-reg move
               so reg-alloc can coalesce it away in the usual way. */
            HReg src = am->Aam.IR.reg;
            addInstr(env, AMD64Instr_Alu64R(Aalu_MOV, AMD64RMI_Reg(src), dst));
         } else {
            addInstr(env, AMD64Instr_Lea64(am,dst));
         }
         return;
      }

      if (ty == Ity_I64 || ty == Ity_I32 
          || ty == Ity_I16 || ty == Ity_I8) {
         AMD64RMI* rmi = iselIntExpr_RMI(env, stmt->Ist.WrTmp.data);
         HReg dst = lookupIRTemp(env, tmp);
         addInstr(env, AMD64Instr_Alu64R(Aalu_MOV,rmi,dst));
         return;
      }
      if (ty == Ity_I128) {
         HReg rHi, rLo, dstHi, dstLo;
         iselInt128Expr(&rHi,&rLo, env, stmt->Ist.WrTmp.data);
         lookupIRTempPair( &dstHi, &dstLo, env, tmp);
         addInstr(env, mk_iMOVsd_RR(rHi,dstHi) );
         addInstr(env, mk_iMOVsd_RR(rLo,dstLo) );
         return;
      }
      if (ty == Ity_I1) {
         AMD64CondCode cond = iselCondCode(env, stmt->Ist.WrTmp.data);
         HReg dst = lookupIRTemp(env, tmp);
         addInstr(env, AMD64Instr_Set64(cond, dst));
         return;
      }
      if (ty == Ity_F64) {
         HReg dst = lookupIRTemp(env, tmp);
         HReg src = iselDblExpr(env, stmt->Ist.WrTmp.data);
         addInstr(env, mk_vMOVsd_RR(src, dst));
         return;
      }
      if (ty == Ity_F32) {
         HReg dst = lookupIRTemp(env, tmp);
         HReg src = iselFltExpr(env, stmt->Ist.WrTmp.data);
         addInstr(env, mk_vMOVsd_RR(src, dst));
         return;
      }
      if (ty == Ity_V128) {
         HReg dst = lookupIRTemp(env, tmp);
         HReg src = iselVecExpr(env, stmt->Ist.WrTmp.data);
         addInstr(env, mk_vMOVsd_RR(src, dst));
         return;
      }
      if (ty == Ity_V256) {
         HReg rHi, rLo, dstHi, dstLo;
         iselDVecExpr(&rHi,&rLo, env, stmt->Ist.WrTmp.data);
         lookupIRTempPair( &dstHi, &dstLo, env, tmp);
         addInstr(env, mk_vMOVsd_RR(rHi,dstHi) );
         addInstr(env, mk_vMOVsd_RR(rLo,dstLo) );
         return;
      }
      break;
   }

   /* --------- Call to DIRTY helper --------- */
   case Ist_Dirty: {
      IRDirty* d = stmt->Ist.Dirty.details;

      /* Figure out the return type, if any. */
      IRType retty = Ity_INVALID;
      if (d->tmp != IRTemp_INVALID)
         retty = typeOfIRTemp(env->type_env, d->tmp);

      /* Throw out any return types we don't know about. */
      Bool retty_ok = False;
      switch (retty) {
         case Ity_INVALID: /* function doesn't return anything */
         case Ity_I64: case Ity_I32: case Ity_I16: case Ity_I8:
         case Ity_V128: case Ity_V256:
            retty_ok = True; break;
         default:
            break;
      }
      if (!retty_ok)
         break; /* will go to stmt_fail: */

      /* Marshal args, do the call, and set the return value to
         0x555..555 if this is a conditional call that returns a value
         and the call is skipped. */
      UInt   addToSp = 0;
      RetLoc rloc    = mk_RetLoc_INVALID();
      doHelperCall( &addToSp, &rloc, env, d->guard, d->cee, retty, d->args );
      vassert(is_sane_RetLoc(rloc));

      /* Now figure out what to do with the returned value, if any. */
      switch (retty) {
         case Ity_INVALID: {
            /* No return value.  Nothing to do. */
            vassert(d->tmp == IRTemp_INVALID);
            vassert(rloc.pri == RLPri_None);
            vassert(addToSp == 0);
            return;
         }
         case Ity_I64: case Ity_I32: case Ity_I16: case Ity_I8: {
            /* The returned value is in %rax.  Park it in the register
               associated with tmp. */
            vassert(rloc.pri == RLPri_Int);
            vassert(addToSp == 0);
            HReg dst = lookupIRTemp(env, d->tmp);
            addInstr(env, mk_iMOVsd_RR(hregAMD64_RAX(),dst) );
            return;
         }
         case Ity_V128: {
            /* The returned value is on the stack, and rloc.spOff
               tells us where.  Fish it off the stack and then move
               the stack pointer upwards to clear it, as directed by
               doHelperCall. */
            vassert(rloc.pri == RLPri_V128SpRel);
            vassert(addToSp >= 16);
            HReg        dst = lookupIRTemp(env, d->tmp);
            AMD64AMode* am  = AMD64AMode_IR(rloc.spOff, hregAMD64_RSP());
            addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 16, dst, am ));
            add_to_rsp(env, addToSp);
            return;
         }
         case Ity_V256: {
            /* See comments for Ity_V128. */
            vassert(rloc.pri == RLPri_V256SpRel);
            vassert(addToSp >= 32);
            HReg        dstLo, dstHi;
            lookupIRTempPair(&dstHi, &dstLo, env, d->tmp);
            AMD64AMode* amLo  = AMD64AMode_IR(rloc.spOff, hregAMD64_RSP());
            addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 16, dstLo, amLo ));
            AMD64AMode* amHi  = AMD64AMode_IR(rloc.spOff+16, hregAMD64_RSP());
            addInstr(env, AMD64Instr_SseLdSt( True/*load*/, 16, dstHi, amHi ));
            add_to_rsp(env, addToSp);
            return;
         }
         default:
            /*NOTREACHED*/
            vassert(0);
      }
      break;
   }

   /* --------- MEM FENCE --------- */
   case Ist_MBE:
      switch (stmt->Ist.MBE.event) {
         case Imbe_Fence:
            addInstr(env, AMD64Instr_MFence());
            return;
         default:
            break;
      }
      break;

   /* --------- ACAS --------- */
   case Ist_CAS:
      if (stmt->Ist.CAS.details->oldHi == IRTemp_INVALID) {
         /* "normal" singleton CAS */
         UChar  sz;
         IRCAS* cas = stmt->Ist.CAS.details;
         IRType ty  = typeOfIRExpr(env->type_env, cas->dataLo);
         /* get: cas->expd into %rax, and cas->data into %rbx */
         AMD64AMode* am = iselIntExpr_AMode(env, cas->addr);
         HReg rData = iselIntExpr_R(env, cas->dataLo);
         HReg rExpd = iselIntExpr_R(env, cas->expdLo);
         HReg rOld  = lookupIRTemp(env, cas->oldLo);
         vassert(cas->expdHi == NULL);
         vassert(cas->dataHi == NULL);
         addInstr(env, mk_iMOVsd_RR(rExpd, rOld));
         addInstr(env, mk_iMOVsd_RR(rExpd, hregAMD64_RAX()));
         addInstr(env, mk_iMOVsd_RR(rData, hregAMD64_RBX()));
         switch (ty) { 
            case Ity_I64: sz = 8; break;
            case Ity_I32: sz = 4; break;
            case Ity_I16: sz = 2; break;
            case Ity_I8:  sz = 1; break; 
            default: goto unhandled_cas;
         }
         addInstr(env, AMD64Instr_ACAS(am, sz));
         addInstr(env, AMD64Instr_CMov64(Acc_NZ, hregAMD64_RAX(), rOld));
         return;
      } else {
         /* double CAS */
         UChar  sz;
         IRCAS* cas = stmt->Ist.CAS.details;
         IRType ty  = typeOfIRExpr(env->type_env, cas->dataLo);
         /* only 32-bit and 64-bit allowed in this case */
         /* get: cas->expdLo into %rax, and cas->dataLo into %rbx */
         /* get: cas->expdHi into %rdx, and cas->dataHi into %rcx */
         AMD64AMode* am = iselIntExpr_AMode(env, cas->addr);
         HReg rDataHi = iselIntExpr_R(env, cas->dataHi);
         HReg rDataLo = iselIntExpr_R(env, cas->dataLo);
         HReg rExpdHi = iselIntExpr_R(env, cas->expdHi);
         HReg rExpdLo = iselIntExpr_R(env, cas->expdLo);
         HReg rOldHi  = lookupIRTemp(env, cas->oldHi);
         HReg rOldLo  = lookupIRTemp(env, cas->oldLo);
         switch (ty) { 
            case Ity_I64:
               if (!(env->hwcaps & VEX_HWCAPS_AMD64_CX16))
                  goto unhandled_cas; /* we'd have to generate
                                         cmpxchg16b, but the host
                                         doesn't support that */
               sz = 8;
               break;
            case Ity_I32:
               sz = 4;
               break;
            default:
               goto unhandled_cas;
         }
         addInstr(env, mk_iMOVsd_RR(rExpdHi, rOldHi));
         addInstr(env, mk_iMOVsd_RR(rExpdLo, rOldLo));
         addInstr(env, mk_iMOVsd_RR(rExpdHi, hregAMD64_RDX()));
         addInstr(env, mk_iMOVsd_RR(rExpdLo, hregAMD64_RAX()));
         addInstr(env, mk_iMOVsd_RR(rDataHi, hregAMD64_RCX()));
         addInstr(env, mk_iMOVsd_RR(rDataLo, hregAMD64_RBX()));
         addInstr(env, AMD64Instr_DACAS(am, sz));
         addInstr(env, AMD64Instr_CMov64(Acc_NZ, hregAMD64_RDX(), rOldHi));
         addInstr(env, AMD64Instr_CMov64(Acc_NZ, hregAMD64_RAX(), rOldLo));
         return;
      }
      unhandled_cas:
      break;

   /* --------- INSTR MARK --------- */
   /* Doesn't generate any executable code ... */
   case Ist_IMark:
       return;

   /* --------- ABI HINT --------- */
   /* These have no meaning (denotation in the IR) and so we ignore
      them ... if any actually made it this far. */
   case Ist_AbiHint:
       return;

   /* --------- NO-OP --------- */
   case Ist_NoOp:
       return;

   /* --------- EXIT --------- */
   case Ist_Exit: {
      if (stmt->Ist.Exit.dst->tag != Ico_U64)
         vpanic("iselStmt(amd64): Ist_Exit: dst is not a 64-bit value");

      AMD64CondCode cc    = iselCondCode(env, stmt->Ist.Exit.guard);
      AMD64AMode*   amRIP = AMD64AMode_IR(stmt->Ist.Exit.offsIP,
                                          hregAMD64_RBP());

      /* Case: boring transfer to known address */
      if (stmt->Ist.Exit.jk == Ijk_Boring) {
         if (env->chainingAllowed) {
            /* .. almost always true .. */
            /* Skip the event check at the dst if this is a forwards
               edge. */
            Bool toFastEP
               = ((Addr64)stmt->Ist.Exit.dst->Ico.U64) > env->max_ga;
            if (0) vex_printf("%s", toFastEP ? "Y" : ",");
            addInstr(env, AMD64Instr_XDirect(stmt->Ist.Exit.dst->Ico.U64,
                                             amRIP, cc, toFastEP));
         } else {
            /* .. very occasionally .. */
            /* We can't use chaining, so ask for an assisted transfer,
               as that's the only alternative that is allowable. */
            HReg r = iselIntExpr_R(env, IRExpr_Const(stmt->Ist.Exit.dst));
            addInstr(env, AMD64Instr_XAssisted(r, amRIP, cc, Ijk_Boring));
         }
         return;
      }

      /* Case: assisted transfer to arbitrary address */
      switch (stmt->Ist.Exit.jk) {
         /* Keep this list in sync with that in iselNext below */
         case Ijk_ClientReq:
         case Ijk_EmWarn:
         case Ijk_NoDecode:
         case Ijk_NoRedir:
         case Ijk_SigSEGV:
         case Ijk_SigTRAP:
         case Ijk_Sys_syscall:
         case Ijk_Sys_int210:
         case Ijk_InvalICache:
         case Ijk_Yield:
         {
            HReg r = iselIntExpr_R(env, IRExpr_Const(stmt->Ist.Exit.dst));
            addInstr(env, AMD64Instr_XAssisted(r, amRIP, cc, stmt->Ist.Exit.jk));
            return;
         }
         default:
            break;
      }

      /* Do we ever expect to see any other kind? */
      goto stmt_fail;
   }

   default: break;
   }
  stmt_fail:
   ppIRStmt(stmt);
   vpanic("iselStmt(amd64)");
}


/*---------------------------------------------------------*/
/*--- ISEL: Basic block terminators (Nexts)             ---*/
/*---------------------------------------------------------*/

static void iselNext ( ISelEnv* env,
                       IRExpr* next, IRJumpKind jk, Int offsIP )
{
   if (vex_traceflags & VEX_TRACE_VCODE) {
      vex_printf( "\n-- PUT(%d) = ", offsIP);
      ppIRExpr( next );
      vex_printf( "; exit-");
      ppIRJumpKind(jk);
      vex_printf( "\n");
   }

   /* Case: boring transfer to known address */
   if (next->tag == Iex_Const) {
      IRConst* cdst = next->Iex.Const.con;
      vassert(cdst->tag == Ico_U64);
      if (jk == Ijk_Boring || jk == Ijk_Call) {
         /* Boring transfer to known address */
         AMD64AMode* amRIP = AMD64AMode_IR(offsIP, hregAMD64_RBP());
         if (env->chainingAllowed) {
            /* .. almost always true .. */
            /* Skip the event check at the dst if this is a forwards
               edge. */
            Bool toFastEP
               = ((Addr64)cdst->Ico.U64) > env->max_ga;
            if (0) vex_printf("%s", toFastEP ? "X" : ".");
            addInstr(env, AMD64Instr_XDirect(cdst->Ico.U64, 
                                             amRIP, Acc_ALWAYS, 
                                             toFastEP));
         } else {
            /* .. very occasionally .. */
            /* We can't use chaining, so ask for an indirect transfer,
               as that's the cheapest alternative that is
               allowable. */
            HReg r = iselIntExpr_R(env, next);
            addInstr(env, AMD64Instr_XAssisted(r, amRIP, Acc_ALWAYS,
                                               Ijk_Boring));
         }
         return;
      }
   }

   /* Case: call/return (==boring) transfer to any address */
   switch (jk) {
      case Ijk_Boring: case Ijk_Ret: case Ijk_Call: {
         HReg        r     = iselIntExpr_R(env, next);
         AMD64AMode* amRIP = AMD64AMode_IR(offsIP, hregAMD64_RBP());
         if (env->chainingAllowed) {
            addInstr(env, AMD64Instr_XIndir(r, amRIP, Acc_ALWAYS));
         } else {
            addInstr(env, AMD64Instr_XAssisted(r, amRIP, Acc_ALWAYS,
                                               Ijk_Boring));
         }
         return;
      }
      default:
         break;
   }

   /* Case: assisted transfer to arbitrary address */
   switch (jk) {
      /* Keep this list in sync with that for Ist_Exit above */
      case Ijk_ClientReq:
      case Ijk_EmWarn:
      case Ijk_NoDecode:
      case Ijk_NoRedir:
      case Ijk_SigSEGV:
      case Ijk_SigTRAP:
      case Ijk_Sys_syscall:
      case Ijk_Sys_int210:
      case Ijk_InvalICache:
      case Ijk_Yield: {
         HReg        r     = iselIntExpr_R(env, next);
         AMD64AMode* amRIP = AMD64AMode_IR(offsIP, hregAMD64_RBP());
         addInstr(env, AMD64Instr_XAssisted(r, amRIP, Acc_ALWAYS, jk));
         return;
      }
      default:
         break;
   }

   vex_printf( "\n-- PUT(%d) = ", offsIP);
   ppIRExpr( next );
   vex_printf( "; exit-");
   ppIRJumpKind(jk);
   vex_printf( "\n");
   vassert(0); // are we expecting any other kind?
}


/*---------------------------------------------------------*/
/*--- Insn selector top-level                           ---*/
/*---------------------------------------------------------*/

/* Translate an entire SB to amd64 code. */

HInstrArray* iselSB_AMD64 ( const IRSB* bb,
                            VexArch      arch_host,
                            const VexArchInfo* archinfo_host,
                            const VexAbiInfo*  vbi/*UNUSED*/,
                            Int offs_Host_EvC_Counter,
                            Int offs_Host_EvC_FailAddr,
                            Bool chainingAllowed,
                            Bool addProfInc,
                            Addr max_ga )
{
   Int        i, j;
   HReg       hreg, hregHI;
   ISelEnv*   env;
   UInt       hwcaps_host = archinfo_host->hwcaps;
   AMD64AMode *amCounter, *amFailAddr;

   /* sanity ... */
   vassert(arch_host == VexArchAMD64);
   vassert(0 == (hwcaps_host
                 & ~(VEX_HWCAPS_AMD64_SSE3
                     | VEX_HWCAPS_AMD64_SSSE3
                     | VEX_HWCAPS_AMD64_CX16
                     | VEX_HWCAPS_AMD64_LZCNT
                     | VEX_HWCAPS_AMD64_AVX
                     | VEX_HWCAPS_AMD64_RDTSCP
                     | VEX_HWCAPS_AMD64_BMI
                     | VEX_HWCAPS_AMD64_AVX2
                     | VEX_HWCAPS_AMD64_F16C
                     | VEX_HWCAPS_AMD64_RDRAND)));

   /* Check that the host's endianness is as expected. */
   vassert(archinfo_host->endness == VexEndnessLE);

   /* Make up an initial environment to use. */
   env = LibVEX_Alloc_inline(sizeof(ISelEnv));
   env->vreg_ctr = 0;

   /* Set up output code array. */
   env->code = newHInstrArray();

   /* Copy BB's type env. */
   env->type_env = bb->tyenv;

   /* Make up an IRTemp -> virtual HReg mapping.  This doesn't
      change as we go along. */
   env->n_vregmap = bb->tyenv->types_used;
   env->vregmap   = LibVEX_Alloc_inline(env->n_vregmap * sizeof(HReg));
   env->vregmapHI = LibVEX_Alloc_inline(env->n_vregmap * sizeof(HReg));

   /* and finally ... */
   env->chainingAllowed = chainingAllowed;
   env->hwcaps          = hwcaps_host;
   env->max_ga          = max_ga;

   /* For each IR temporary, allocate a suitably-kinded virtual
      register. */
   j = 0;
   for (i = 0; i < env->n_vregmap; i++) {
      hregHI = hreg = INVALID_HREG;
      switch (bb->tyenv->types[i]) {
         case Ity_I1:
         case Ity_I8: case Ity_I16: case Ity_I32: case Ity_I64:
            hreg = mkHReg(True, HRcInt64, 0, j++);
            break;
         case Ity_I128:
            hreg   = mkHReg(True, HRcInt64, 0, j++);
            hregHI = mkHReg(True, HRcInt64, 0, j++);
            break;
         case Ity_F32:
         case Ity_F64:
         case Ity_V128:
            hreg = mkHReg(True, HRcVec128, 0, j++);
            break;
         case Ity_V256:
            hreg   = mkHReg(True, HRcVec128, 0, j++);
            hregHI = mkHReg(True, HRcVec128, 0, j++);
            break;
         default:
            ppIRType(bb->tyenv->types[i]);
            vpanic("iselBB(amd64): IRTemp type");
      }
      env->vregmap[i]   = hreg;
      env->vregmapHI[i] = hregHI;
   }
   env->vreg_ctr = j;

   /* The very first instruction must be an event check. */
   amCounter  = AMD64AMode_IR(offs_Host_EvC_Counter,  hregAMD64_RBP());
   amFailAddr = AMD64AMode_IR(offs_Host_EvC_FailAddr, hregAMD64_RBP());
   addInstr(env, AMD64Instr_EvCheck(amCounter, amFailAddr));

   /* Possibly a block counter increment (for profiling).  At this
      point we don't know the address of the counter, so just pretend
      it is zero.  It will have to be patched later, but before this
      translation is used, by a call to LibVEX_patchProfCtr. */
   if (addProfInc) {
      addInstr(env, AMD64Instr_ProfInc());
   }

   /* Ok, finally we can iterate over the statements. */
   for (i = 0; i < bb->stmts_used; i++)
      if (bb->stmts[i])
         iselStmt(env, bb->stmts[i]);

   iselNext(env, bb->next, bb->jumpkind, bb->offsIP);

   /* record the number of vregs we used. */
   env->code->n_vregs = env->vreg_ctr;
   return env->code;
}


/*---------------------------------------------------------------*/
/*--- end                                   host_amd64_isel.c ---*/
/*---------------------------------------------------------------*/