gcc/gimple-isel.cc

   1 /* Schedule GIMPLE vector statements.
   2    Copyright (C) 2020-2021 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 gimple *
  53 gimple_expand_vec_set_expr (gimple_stmt_iterator *gsi)
  54 {
  55   enum tree_code code;
  56   gcall *new_stmt = NULL;
  57   gassign *ass_stmt = NULL;
  58
  59   /* Only consider code == GIMPLE_ASSIGN.  */
  60   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
  61   if (!stmt)
  62     return NULL;
  63
  64   tree lhs = gimple_assign_lhs (stmt);
  65   code = TREE_CODE (lhs);
  66   if (code != ARRAY_REF)
  67     return NULL;
  68
  69   tree val = gimple_assign_rhs1 (stmt);
  70   tree op0 = TREE_OPERAND (lhs, 0);
  71   if (TREE_CODE (op0) == VIEW_CONVERT_EXPR && DECL_P (TREE_OPERAND (op0, 0))
  72       && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))
  73       && TYPE_MODE (TREE_TYPE (lhs))
  74            == TYPE_MODE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (op0, 0)))))
  75     {
  76       tree pos = TREE_OPERAND (lhs, 1);
  77       tree view_op0 = TREE_OPERAND (op0, 0);
  78       machine_mode outermode = TYPE_MODE (TREE_TYPE (view_op0));
  79       if (auto_var_in_fn_p (view_op0, cfun->decl)
  80           && !TREE_ADDRESSABLE (view_op0) && can_vec_set_var_idx_p (outermode))
  81         {
  82           location_t loc = gimple_location (stmt);
  83           tree var_src = make_ssa_name (TREE_TYPE (view_op0));
  84           tree var_dst = make_ssa_name (TREE_TYPE (view_op0));
  85
  86           ass_stmt = gimple_build_assign (var_src, view_op0);
  87           gimple_set_vuse (ass_stmt, gimple_vuse (stmt));
  88           gimple_set_location (ass_stmt, loc);
  89           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
  90
  91           new_stmt
  92             = gimple_build_call_internal (IFN_VEC_SET, 3, var_src, val, pos);
  93           gimple_call_set_lhs (new_stmt, var_dst);
  94           gimple_set_location (new_stmt, loc);
  95           gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
  96
  97           ass_stmt = gimple_build_assign (view_op0, var_dst);
  98           gimple_set_location (ass_stmt, loc);
  99           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
 100
 101           gimple_move_vops (ass_stmt, stmt);
 102           gsi_remove (gsi, true);
 103         }
 104     }
 105
 106   return ass_stmt;
 107 }
 108
 109 /* Expand all VEC_COND_EXPR gimple assignments into calls to internal
 110    function based on type of selected expansion.  */
 111
 112 static gimple *
 113 gimple_expand_vec_cond_expr (gimple_stmt_iterator *gsi,
 114                              hash_map<tree, unsigned int> *vec_cond_ssa_name_uses)
 115 {
 116   tree lhs, op0a = NULL_TREE, op0b = NULL_TREE;
 117   enum tree_code code;
 118   enum tree_code tcode;
 119   machine_mode cmp_op_mode;
 120   bool unsignedp;
 121   enum insn_code icode;
 122   imm_use_iterator imm_iter;
 123
 124   /* Only consider code == GIMPLE_ASSIGN.  */
 125   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
 126   if (!stmt)
 127     return NULL;
 128
 129   code = gimple_assign_rhs_code (stmt);
 130   if (code != VEC_COND_EXPR)
 131     return NULL;
 132
 133   tree op0 = gimple_assign_rhs1 (stmt);
 134   tree op1 = gimple_assign_rhs2 (stmt);
 135   tree op2 = gimple_assign_rhs3 (stmt);
 136   lhs = gimple_assign_lhs (stmt);
 137   machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
 138
 139   /* Lower mask typed, non-vector mode VEC_COND_EXPRs to bitwise operations.
 140      Those can end up generated by folding and at least for integer mode masks
 141      we cannot expect vcond expanders to exist.  We lower a ? b : c
 142      to (b & a) | (c & ~a).  */
 143   if (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (lhs))
 144       && !VECTOR_MODE_P (mode))
 145     {
 146       gcc_assert (types_compatible_p (TREE_TYPE (op0), TREE_TYPE (op1)));
 147       gimple_seq stmts = NULL;
 148       tree type = TREE_TYPE (lhs);
 149       location_t loc = gimple_location (stmt);
 150       tree tem0 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op1, op0);
 151       tree tem1 = gimple_build (&stmts, loc, BIT_NOT_EXPR, type, op0);
 152       tree tem2 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op2, tem1);
 153       tree tem3 = gimple_build (&stmts, loc, BIT_IOR_EXPR, type, tem0, tem2);
 154       gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
 155       return gimple_build_assign (lhs, tem3);
 156     }
 157
 158   bool can_compute_op0 = true;
 159   gcc_assert (!COMPARISON_CLASS_P (op0));
 160   if (TREE_CODE (op0) == SSA_NAME)
 161     {
 162       unsigned int used_vec_cond_exprs = 0;
 163       unsigned int *slot = vec_cond_ssa_name_uses->get (op0);
 164       if (slot)
 165         used_vec_cond_exprs = *slot;
 166       else
 167         {
 168           gimple *use_stmt;
 169           FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, op0)
 170             {
 171               gassign *assign = dyn_cast<gassign *> (use_stmt);
 172               if (assign != NULL
 173                   && gimple_assign_rhs_code (assign) == VEC_COND_EXPR
 174                   && gimple_assign_rhs1 (assign) == op0)
 175                 used_vec_cond_exprs++;
 176             }
 177           vec_cond_ssa_name_uses->put (op0, used_vec_cond_exprs);
 178         }
 179
 180       gassign *def_stmt = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (op0));
 181       if (def_stmt)
 182         {
 183           tcode = gimple_assign_rhs_code (def_stmt);
 184           op0a = gimple_assign_rhs1 (def_stmt);
 185           op0b = gimple_assign_rhs2 (def_stmt);
 186
 187           tree op0_type = TREE_TYPE (op0);
 188           tree op0a_type = TREE_TYPE (op0a);
 189           if (TREE_CODE_CLASS (tcode) == tcc_comparison)
 190             can_compute_op0 = expand_vec_cmp_expr_p (op0a_type, op0_type,
 191                                                      tcode);
 192
 193           /* Try to fold x CMP y ? -1 : 0 to x CMP y.  */
 194
 195           if (can_compute_op0
 196               && integer_minus_onep (op1)
 197               && integer_zerop (op2)
 198               && TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (TREE_TYPE (op0)))
 199             {
 200               tree conv_op = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), op0);
 201               gassign *new_stmt = gimple_build_assign (lhs, conv_op);
 202               gsi_replace (gsi, new_stmt, true);
 203               return new_stmt;
 204             }
 205
 206           if (can_compute_op0
 207               && used_vec_cond_exprs >= 2
 208               && (get_vcond_mask_icode (mode, TYPE_MODE (op0_type))
 209                   != CODE_FOR_nothing))
 210             {
 211               /* Keep the SSA name and use vcond_mask.  */
 212               tcode = TREE_CODE (op0);
 213             }
 214         }
 215       else
 216         tcode = TREE_CODE (op0);
 217     }
 218   else
 219     tcode = TREE_CODE (op0);
 220
 221   if (TREE_CODE_CLASS (tcode) != tcc_comparison)
 222     {
 223       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0)));
 224       if (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 225           != CODE_FOR_nothing)
 226         return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 227       /* Fake op0 < 0.  */
 228       else
 229         {
 230           gcc_assert (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (op0)))
 231                       == MODE_VECTOR_INT);
 232           op0a = op0;
 233           op0b = build_zero_cst (TREE_TYPE (op0));
 234           tcode = LT_EXPR;
 235         }
 236     }
 237   cmp_op_mode = TYPE_MODE (TREE_TYPE (op0a));
 238   unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
 239
 240   gcc_assert (known_eq (GET_MODE_NUNITS (mode),
 241                         GET_MODE_NUNITS (cmp_op_mode)));
 242
 243   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
 244   if (icode == CODE_FOR_nothing)
 245     {
 246       if (tcode == LT_EXPR
 247           && op0a == op0)
 248         {
 249           /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
 250              into a constant when only get_vcond_eq_icode is supported.
 251              Try changing it to NE_EXPR.  */
 252           tcode = NE_EXPR;
 253         }
 254       if ((tcode == EQ_EXPR || tcode == NE_EXPR)
 255           && direct_internal_fn_supported_p (IFN_VCONDEQ, TREE_TYPE (lhs),
 256                                              TREE_TYPE (op0a),
 257                                              OPTIMIZE_FOR_BOTH))
 258         {
 259           tree tcode_tree = build_int_cst (integer_type_node, tcode);
 260           return gimple_build_call_internal (IFN_VCONDEQ, 5, op0a, op0b, op1,
 261                                              op2, tcode_tree);
 262         }
 263
 264       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0))
 265                   && can_compute_op0
 266                   && (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 267                       != CODE_FOR_nothing));
 268       return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 269     }
 270
 271   tree tcode_tree = build_int_cst (integer_type_node, tcode);
 272   return gimple_build_call_internal (unsignedp ? IFN_VCONDU : IFN_VCOND,
 273                                      5, op0a, op0b, op1, op2, tcode_tree);
 274 }
 275
 276
 277
 278 /* Iterate all gimple statements and try to expand
 279    VEC_COND_EXPR assignments.  */
 280
 281 static unsigned int
 282 gimple_expand_vec_exprs (void)
 283 {
 284   gimple_stmt_iterator gsi;
 285   basic_block bb;
 286   hash_map<tree, unsigned int> vec_cond_ssa_name_uses;
 287   auto_bitmap dce_ssa_names;
 288
 289   FOR_EACH_BB_FN (bb, cfun)
 290     {
 291       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 292         {
 293           gimple *g = gimple_expand_vec_cond_expr (&gsi,
 294                                                    &vec_cond_ssa_name_uses);
 295           if (g != NULL)
 296             {
 297               tree lhs = gimple_assign_lhs (gsi_stmt (gsi));
 298               gimple_set_lhs (g, lhs);
 299               gsi_replace (&gsi, g, false);
 300             }
 301
 302           gimple_expand_vec_set_expr (&gsi);
 303           if (gsi_end_p (gsi))
 304             break;
 305         }
 306     }
 307
 308   for (hash_map<tree, unsigned int>::iterator it = vec_cond_ssa_name_uses.begin ();
 309        it != vec_cond_ssa_name_uses.end (); ++it)
 310     bitmap_set_bit (dce_ssa_names, SSA_NAME_VERSION ((*it).first));
 311
 312   simple_dce_from_worklist (dce_ssa_names);
 313
 314   return 0;
 315 }
 316
 317 namespace {
 318
 319 const pass_data pass_data_gimple_isel =
 320 {
 321   GIMPLE_PASS, /* type */
 322   "isel", /* name */
 323   OPTGROUP_VEC, /* optinfo_flags */
 324   TV_NONE, /* tv_id */
 325   PROP_cfg, /* properties_required */
 326   0, /* properties_provided */
 327   0, /* properties_destroyed */
 328   0, /* todo_flags_start */
 329   TODO_update_ssa, /* todo_flags_finish */
 330 };
 331
 332 class pass_gimple_isel : public gimple_opt_pass
 333 {
 334 public:
 335   pass_gimple_isel (gcc::context *ctxt)
 336     : gimple_opt_pass (pass_data_gimple_isel, ctxt)
 337   {}
 338
 339   /* opt_pass methods: */
 340   virtual bool gate (function *)
 341     {
 342       return true;
 343     }
 344
 345   virtual unsigned int execute (function *)
 346     {
 347       return gimple_expand_vec_exprs ();
 348     }
 349
 350 }; // class pass_gimple_isel
 351
 352 } // anon namespace
 353
 354 gimple_opt_pass *
 355 make_pass_gimple_isel (gcc::context *ctxt)
 356 {
 357   return new pass_gimple_isel (ctxt);
 358 }
 359