gcc/gimple-isel.cc

   1 /* Schedule GIMPLE vector statements.
   2    Copyright (C) 2020-2022 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "backend.h"
  24 #include "rtl.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "tree-pass.h"
  28 #include "ssa.h"
  29 #include "expmed.h"
  30 #include "optabs-tree.h"
  31 #include "tree-eh.h"
  32 #include "gimple-iterator.h"
  33 #include "gimplify-me.h"
  34 #include "gimplify.h"
  35 #include "tree-cfg.h"
  36 #include "bitmap.h"
  37 #include "tree-ssa-dce.h"
  38 #include "memmodel.h"
  39 #include "optabs.h"
  40 #include "gimple-fold.h"
  41 #include "internal-fn.h"
  42
  43 /* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to
  44    internal function based on vector type of selected expansion.
  45    i.e.:
  46      VIEW_CONVERT_EXPR<int[4]>(u)[_1] =  = i_4(D);
  47    =>
  48      _7 = u;
  49      _8 = .VEC_SET (_7, i_4(D), _1);
  50      u = _8;  */
  51
  52 static bool
  53 gimple_expand_vec_set_expr (struct function *fun, gimple_stmt_iterator *gsi)
  54 {
  55   enum tree_code code;
  56   gcall *new_stmt = NULL;
  57   gassign *ass_stmt = NULL;
  58   bool cfg_changed = false;
  59
  60   /* Only consider code == GIMPLE_ASSIGN.  */
  61   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
  62   if (!stmt)
  63     return false;
  64
  65   tree lhs = gimple_assign_lhs (stmt);
  66   code = TREE_CODE (lhs);
  67   if (code != ARRAY_REF)
  68     return false;
  69
  70   tree val = gimple_assign_rhs1 (stmt);
  71   tree op0 = TREE_OPERAND (lhs, 0);
  72   if (TREE_CODE (op0) == VIEW_CONVERT_EXPR && DECL_P (TREE_OPERAND (op0, 0))
  73       && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))
  74       && TYPE_MODE (TREE_TYPE (lhs))
  75            == TYPE_MODE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (op0, 0)))))
  76     {
  77       tree pos = TREE_OPERAND (lhs, 1);
  78       tree view_op0 = TREE_OPERAND (op0, 0);
  79       machine_mode outermode = TYPE_MODE (TREE_TYPE (view_op0));
  80       if (auto_var_in_fn_p (view_op0, fun->decl)
  81           && !TREE_ADDRESSABLE (view_op0) && can_vec_set_var_idx_p (outermode))
  82         {
  83           location_t loc = gimple_location (stmt);
  84           tree var_src = make_ssa_name (TREE_TYPE (view_op0));
  85           tree var_dst = make_ssa_name (TREE_TYPE (view_op0));
  86
  87           ass_stmt = gimple_build_assign (var_src, view_op0);
  88           gimple_set_vuse (ass_stmt, gimple_vuse (stmt));
  89           gimple_set_location (ass_stmt, loc);
  90           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
  91
  92           new_stmt
  93             = gimple_build_call_internal (IFN_VEC_SET, 3, var_src, val, pos);
  94           gimple_call_set_lhs (new_stmt, var_dst);
  95           gimple_set_location (new_stmt, loc);
  96           gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
  97
  98           ass_stmt = gimple_build_assign (view_op0, var_dst);
  99           gimple_set_location (ass_stmt, loc);
 100           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
 101
 102           basic_block bb = gimple_bb (stmt);
 103           gimple_move_vops (ass_stmt, stmt);
 104           if (gsi_remove (gsi, true)
 105               && gimple_purge_dead_eh_edges (bb))
 106             cfg_changed = true;
 107         }
 108     }
 109
 110   return cfg_changed;
 111 }
 112
 113 /* Expand all VEC_COND_EXPR gimple assignments into calls to internal
 114    function based on type of selected expansion.  */
 115
 116 static gimple *
 117 gimple_expand_vec_cond_expr (struct function *fun, gimple_stmt_iterator *gsi,
 118                              hash_map<tree, unsigned int> *vec_cond_ssa_name_uses)
 119 {
 120   tree lhs, op0a = NULL_TREE, op0b = NULL_TREE;
 121   enum tree_code code;
 122   enum tree_code tcode;
 123   machine_mode cmp_op_mode;
 124   bool unsignedp;
 125   enum insn_code icode;
 126   imm_use_iterator imm_iter;
 127
 128   /* Only consider code == GIMPLE_ASSIGN.  */
 129   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
 130   if (!stmt)
 131     return NULL;
 132
 133   code = gimple_assign_rhs_code (stmt);
 134   if (code != VEC_COND_EXPR)
 135     return NULL;
 136
 137   tree op0 = gimple_assign_rhs1 (stmt);
 138   tree op1 = gimple_assign_rhs2 (stmt);
 139   tree op2 = gimple_assign_rhs3 (stmt);
 140   lhs = gimple_assign_lhs (stmt);
 141   machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
 142
 143   /* Lower mask typed, non-vector mode VEC_COND_EXPRs to bitwise operations.
 144      Those can end up generated by folding and at least for integer mode masks
 145      we cannot expect vcond expanders to exist.  We lower a ? b : c
 146      to (b & a) | (c & ~a).  */
 147   if (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (lhs))
 148       && !VECTOR_MODE_P (mode))
 149     {
 150       gcc_assert (types_compatible_p (TREE_TYPE (op0), TREE_TYPE (op1)));
 151       gimple_seq stmts = NULL;
 152       tree type = TREE_TYPE (lhs);
 153       location_t loc = gimple_location (stmt);
 154       tree tem0 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op1, op0);
 155       tree tem1 = gimple_build (&stmts, loc, BIT_NOT_EXPR, type, op0);
 156       tree tem2 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op2, tem1);
 157       tree tem3 = gimple_build (&stmts, loc, BIT_IOR_EXPR, type, tem0, tem2);
 158       gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
 159       return gimple_build_assign (lhs, tem3);
 160     }
 161
 162   bool can_compute_op0 = true;
 163   gcc_assert (!COMPARISON_CLASS_P (op0));
 164   if (TREE_CODE (op0) == SSA_NAME)
 165     {
 166       unsigned int used_vec_cond_exprs = 0;
 167       unsigned int *slot = vec_cond_ssa_name_uses->get (op0);
 168       if (slot)
 169         used_vec_cond_exprs = *slot;
 170       else
 171         {
 172           gimple *use_stmt;
 173           FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, op0)
 174             {
 175               gassign *assign = dyn_cast<gassign *> (use_stmt);
 176               if (assign != NULL
 177                   && gimple_assign_rhs_code (assign) == VEC_COND_EXPR
 178                   && gimple_assign_rhs1 (assign) == op0)
 179                 used_vec_cond_exprs++;
 180             }
 181           vec_cond_ssa_name_uses->put (op0, used_vec_cond_exprs);
 182         }
 183
 184       gassign *def_stmt = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (op0));
 185       if (def_stmt)
 186         {
 187           tcode = gimple_assign_rhs_code (def_stmt);
 188           op0a = gimple_assign_rhs1 (def_stmt);
 189           op0b = gimple_assign_rhs2 (def_stmt);
 190
 191           tree op0_type = TREE_TYPE (op0);
 192           tree op0a_type = TREE_TYPE (op0a);
 193           if (TREE_CODE_CLASS (tcode) == tcc_comparison)
 194             can_compute_op0 = expand_vec_cmp_expr_p (op0a_type, op0_type,
 195                                                      tcode);
 196
 197           /* Try to fold x CMP y ? -1 : 0 to x CMP y.  */
 198           if (can_compute_op0
 199               && integer_minus_onep (op1)
 200               && integer_zerop (op2)
 201               && TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (TREE_TYPE (op0)))
 202             {
 203               tree conv_op = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), op0);
 204               gassign *new_stmt = gimple_build_assign (lhs, conv_op);
 205               gsi_replace (gsi, new_stmt, true);
 206               return new_stmt;
 207             }
 208
 209           /* When the compare has EH we do not want to forward it when
 210              it has multiple uses and in general because of the complication
 211              with EH redirection.  */
 212           if (stmt_can_throw_internal (fun, def_stmt))
 213             tcode = TREE_CODE (op0);
 214
 215           /* If we can compute op0 and have multiple uses, keep the SSA
 216              name and use vcond_mask.  */
 217           else if (can_compute_op0
 218                    && used_vec_cond_exprs >= 2
 219                    && (get_vcond_mask_icode (mode, TYPE_MODE (op0_type))
 220                        != CODE_FOR_nothing))
 221             tcode = TREE_CODE (op0);
 222         }
 223       else
 224         tcode = TREE_CODE (op0);
 225     }
 226   else
 227     tcode = TREE_CODE (op0);
 228
 229   if (TREE_CODE_CLASS (tcode) != tcc_comparison)
 230     {
 231       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0)));
 232       if (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 233           != CODE_FOR_nothing)
 234         return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 235       /* Fake op0 < 0.  */
 236       else
 237         {
 238           gcc_assert (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (op0)))
 239                       == MODE_VECTOR_INT);
 240           op0a = op0;
 241           op0b = build_zero_cst (TREE_TYPE (op0));
 242           tcode = LT_EXPR;
 243         }
 244     }
 245   cmp_op_mode = TYPE_MODE (TREE_TYPE (op0a));
 246   unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
 247
 248   gcc_assert (known_eq (GET_MODE_NUNITS (mode),
 249                         GET_MODE_NUNITS (cmp_op_mode)));
 250
 251   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
 252   /* Some targets do not have vcondeq and only vcond with NE/EQ
 253      but not vcondu, so make sure to also try vcond here as
 254      vcond_icode_p would canonicalize the optab query to.  */
 255   if (icode == CODE_FOR_nothing
 256       && (tcode == NE_EXPR || tcode == EQ_EXPR)
 257       && ((icode = get_vcond_icode (mode, cmp_op_mode, !unsignedp))
 258           != CODE_FOR_nothing))
 259     unsignedp = !unsignedp;
 260   if (icode == CODE_FOR_nothing)
 261     {
 262       if (tcode == LT_EXPR
 263           && op0a == op0)
 264         {
 265           /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
 266              into a constant when only get_vcond_eq_icode is supported.
 267              Try changing it to NE_EXPR.  */
 268           tcode = NE_EXPR;
 269         }
 270       if ((tcode == EQ_EXPR || tcode == NE_EXPR)
 271           && direct_internal_fn_supported_p (IFN_VCONDEQ, TREE_TYPE (lhs),
 272                                              TREE_TYPE (op0a),
 273                                              OPTIMIZE_FOR_BOTH))
 274         {
 275           tree tcode_tree = build_int_cst (integer_type_node, tcode);
 276           return gimple_build_call_internal (IFN_VCONDEQ, 5, op0a, op0b, op1,
 277                                              op2, tcode_tree);
 278         }
 279
 280       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0))
 281                   && can_compute_op0
 282                   && (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 283                       != CODE_FOR_nothing));
 284       return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 285     }
 286
 287   tree tcode_tree = build_int_cst (integer_type_node, tcode);
 288   return gimple_build_call_internal (unsignedp ? IFN_VCONDU : IFN_VCOND,
 289                                      5, op0a, op0b, op1, op2, tcode_tree);
 290 }
 291
 292
 293
 294 /* Iterate all gimple statements and try to expand
 295    VEC_COND_EXPR assignments.  */
 296
 297 static unsigned int
 298 gimple_expand_vec_exprs (struct function *fun)
 299 {
 300   gimple_stmt_iterator gsi;
 301   basic_block bb;
 302   hash_map<tree, unsigned int> vec_cond_ssa_name_uses;
 303   auto_bitmap dce_ssa_names;
 304   bool cfg_changed = false;
 305
 306   FOR_EACH_BB_FN (bb, fun)
 307     {
 308       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 309         {
 310           gimple *g = gimple_expand_vec_cond_expr (fun, &gsi,
 311                                                    &vec_cond_ssa_name_uses);
 312           if (g != NULL)
 313             {
 314               tree lhs = gimple_assign_lhs (gsi_stmt (gsi));
 315               gimple_set_lhs (g, lhs);
 316               gsi_replace (&gsi, g, false);
 317             }
 318
 319           cfg_changed |= gimple_expand_vec_set_expr (fun, &gsi);
 320           if (gsi_end_p (gsi))
 321             break;
 322         }
 323     }
 324
 325   for (hash_map<tree, unsigned int>::iterator it = vec_cond_ssa_name_uses.begin ();
 326        it != vec_cond_ssa_name_uses.end (); ++it)
 327     bitmap_set_bit (dce_ssa_names, SSA_NAME_VERSION ((*it).first));
 328
 329   simple_dce_from_worklist (dce_ssa_names);
 330
 331   return cfg_changed ? TODO_cleanup_cfg : 0;
 332 }
 333
 334 namespace {
 335
 336 const pass_data pass_data_gimple_isel =
 337 {
 338   GIMPLE_PASS, /* type */
 339   "isel", /* name */
 340   OPTGROUP_VEC, /* optinfo_flags */
 341   TV_NONE, /* tv_id */
 342   PROP_cfg, /* properties_required */
 343   0, /* properties_provided */
 344   0, /* properties_destroyed */
 345   0, /* todo_flags_start */
 346   TODO_update_ssa, /* todo_flags_finish */
 347 };
 348
 349 class pass_gimple_isel : public gimple_opt_pass
 350 {
 351 public:
 352   pass_gimple_isel (gcc::context *ctxt)
 353     : gimple_opt_pass (pass_data_gimple_isel, ctxt)
 354   {}
 355
 356   /* opt_pass methods: */
 357   virtual bool gate (function *)
 358     {
 359       return true;
 360     }
 361
 362   virtual unsigned int execute (function *fun)
 363     {
 364       return gimple_expand_vec_exprs (fun);
 365     }
 366
 367 }; // class pass_gimple_isel
 368
 369 } // anon namespace
 370
 371 gimple_opt_pass *
 372 make_pass_gimple_isel (gcc::context *ctxt)
 373 {
 374   return new pass_gimple_isel (ctxt);
 375 }
 376