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           *gsi = gsi_for_stmt (ass_stmt);
 108         }
 109     }
 110
 111   return cfg_changed;
 112 }
 113
 114 /* Expand all VEC_COND_EXPR gimple assignments into calls to internal
 115    function based on type of selected expansion.  */
 116
 117 static gimple *
 118 gimple_expand_vec_cond_expr (struct function *fun, gimple_stmt_iterator *gsi,
 119                              hash_map<tree, unsigned int> *vec_cond_ssa_name_uses)
 120 {
 121   tree lhs, op0a = NULL_TREE, op0b = NULL_TREE;
 122   enum tree_code code;
 123   enum tree_code tcode;
 124   machine_mode cmp_op_mode;
 125   bool unsignedp;
 126   enum insn_code icode;
 127   imm_use_iterator imm_iter;
 128
 129   /* Only consider code == GIMPLE_ASSIGN.  */
 130   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
 131   if (!stmt)
 132     return NULL;
 133
 134   code = gimple_assign_rhs_code (stmt);
 135   if (code != VEC_COND_EXPR)
 136     return NULL;
 137
 138   tree op0 = gimple_assign_rhs1 (stmt);
 139   tree op1 = gimple_assign_rhs2 (stmt);
 140   tree op2 = gimple_assign_rhs3 (stmt);
 141   lhs = gimple_assign_lhs (stmt);
 142   machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
 143
 144   /* Lower mask typed, non-vector mode VEC_COND_EXPRs to bitwise operations.
 145      Those can end up generated by folding and at least for integer mode masks
 146      we cannot expect vcond expanders to exist.  We lower a ? b : c
 147      to (b & a) | (c & ~a).  */
 148   if (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (lhs))
 149       && !VECTOR_MODE_P (mode))
 150     {
 151       gcc_assert (types_compatible_p (TREE_TYPE (op0), TREE_TYPE (op1)));
 152       gimple_seq stmts = NULL;
 153       tree type = TREE_TYPE (lhs);
 154       location_t loc = gimple_location (stmt);
 155       tree tem0 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op1, op0);
 156       tree tem1 = gimple_build (&stmts, loc, BIT_NOT_EXPR, type, op0);
 157       tree tem2 = gimple_build (&stmts, loc, BIT_AND_EXPR, type, op2, tem1);
 158       tree tem3 = gimple_build (&stmts, loc, BIT_IOR_EXPR, type, tem0, tem2);
 159       gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
 160       return gimple_build_assign (lhs, tem3);
 161     }
 162
 163   bool can_compute_op0 = true;
 164   gcc_assert (!COMPARISON_CLASS_P (op0));
 165   if (TREE_CODE (op0) == SSA_NAME)
 166     {
 167       unsigned int used_vec_cond_exprs = 0;
 168       unsigned int *slot = vec_cond_ssa_name_uses->get (op0);
 169       if (slot)
 170         used_vec_cond_exprs = *slot;
 171       else
 172         {
 173           gimple *use_stmt;
 174           FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, op0)
 175             {
 176               gassign *assign = dyn_cast<gassign *> (use_stmt);
 177               if (assign != NULL
 178                   && gimple_assign_rhs_code (assign) == VEC_COND_EXPR
 179                   && gimple_assign_rhs1 (assign) == op0)
 180                 used_vec_cond_exprs++;
 181             }
 182           vec_cond_ssa_name_uses->put (op0, used_vec_cond_exprs);
 183         }
 184
 185       gassign *def_stmt = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (op0));
 186       if (def_stmt)
 187         {
 188           tcode = gimple_assign_rhs_code (def_stmt);
 189           op0a = gimple_assign_rhs1 (def_stmt);
 190           op0b = gimple_assign_rhs2 (def_stmt);
 191
 192           tree op0_type = TREE_TYPE (op0);
 193           tree op0a_type = TREE_TYPE (op0a);
 194           if (TREE_CODE_CLASS (tcode) == tcc_comparison)
 195             can_compute_op0 = expand_vec_cmp_expr_p (op0a_type, op0_type,
 196                                                      tcode);
 197
 198           /* Try to fold x CMP y ? -1 : 0 to x CMP y.  */
 199           if (can_compute_op0
 200               && integer_minus_onep (op1)
 201               && integer_zerop (op2)
 202               && TYPE_MODE (TREE_TYPE (lhs)) == TYPE_MODE (TREE_TYPE (op0)))
 203             {
 204               tree conv_op = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), op0);
 205               gassign *new_stmt = gimple_build_assign (lhs, conv_op);
 206               gsi_replace (gsi, new_stmt, true);
 207               return new_stmt;
 208             }
 209
 210           /* When the compare has EH we do not want to forward it when
 211              it has multiple uses and in general because of the complication
 212              with EH redirection.  */
 213           if (stmt_can_throw_internal (fun, def_stmt))
 214             tcode = TREE_CODE (op0);
 215
 216           /* If we can compute op0 and have multiple uses, keep the SSA
 217              name and use vcond_mask.  */
 218           else if (can_compute_op0
 219                    && used_vec_cond_exprs >= 2
 220                    && (get_vcond_mask_icode (mode, TYPE_MODE (op0_type))
 221                        != CODE_FOR_nothing))
 222             tcode = TREE_CODE (op0);
 223         }
 224       else
 225         tcode = TREE_CODE (op0);
 226     }
 227   else
 228     tcode = TREE_CODE (op0);
 229
 230   if (TREE_CODE_CLASS (tcode) != tcc_comparison)
 231     {
 232       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0)));
 233       if (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 234           != CODE_FOR_nothing)
 235         return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 236       /* Fake op0 < 0.  */
 237       else
 238         {
 239           gcc_assert (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (op0)))
 240                       == MODE_VECTOR_INT);
 241           op0a = op0;
 242           op0b = build_zero_cst (TREE_TYPE (op0));
 243           tcode = LT_EXPR;
 244         }
 245     }
 246   cmp_op_mode = TYPE_MODE (TREE_TYPE (op0a));
 247   unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
 248
 249   gcc_assert (known_eq (GET_MODE_NUNITS (mode),
 250                         GET_MODE_NUNITS (cmp_op_mode)));
 251
 252   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
 253   /* Some targets do not have vcondeq and only vcond with NE/EQ
 254      but not vcondu, so make sure to also try vcond here as
 255      vcond_icode_p would canonicalize the optab query to.  */
 256   if (icode == CODE_FOR_nothing
 257       && (tcode == NE_EXPR || tcode == EQ_EXPR)
 258       && ((icode = get_vcond_icode (mode, cmp_op_mode, !unsignedp))
 259           != CODE_FOR_nothing))
 260     unsignedp = !unsignedp;
 261   if (icode == CODE_FOR_nothing)
 262     {
 263       if (tcode == LT_EXPR
 264           && op0a == op0)
 265         {
 266           /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
 267              into a constant when only get_vcond_eq_icode is supported.
 268              Try changing it to NE_EXPR.  */
 269           tcode = NE_EXPR;
 270         }
 271       if ((tcode == EQ_EXPR || tcode == NE_EXPR)
 272           && direct_internal_fn_supported_p (IFN_VCONDEQ, TREE_TYPE (lhs),
 273                                              TREE_TYPE (op0a),
 274                                              OPTIMIZE_FOR_BOTH))
 275         {
 276           tree tcode_tree = build_int_cst (integer_type_node, tcode);
 277           return gimple_build_call_internal (IFN_VCONDEQ, 5, op0a, op0b, op1,
 278                                              op2, tcode_tree);
 279         }
 280
 281       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0))
 282                   && can_compute_op0
 283                   && (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 284                       != CODE_FOR_nothing));
 285       return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 286     }
 287
 288   tree tcode_tree = build_int_cst (integer_type_node, tcode);
 289   return gimple_build_call_internal (unsignedp ? IFN_VCONDU : IFN_VCOND,
 290                                      5, op0a, op0b, op1, op2, tcode_tree);
 291 }
 292
 293
 294
 295 /* Iterate all gimple statements and try to expand
 296    VEC_COND_EXPR assignments.  */
 297
 298 static unsigned int
 299 gimple_expand_vec_exprs (struct function *fun)
 300 {
 301   gimple_stmt_iterator gsi;
 302   basic_block bb;
 303   hash_map<tree, unsigned int> vec_cond_ssa_name_uses;
 304   auto_bitmap dce_ssa_names;
 305   bool cfg_changed = false;
 306
 307   FOR_EACH_BB_FN (bb, fun)
 308     {
 309       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 310         {
 311           gimple *g = gimple_expand_vec_cond_expr (fun, &gsi,
 312                                                    &vec_cond_ssa_name_uses);
 313           if (g != NULL)
 314             {
 315               tree lhs = gimple_assign_lhs (gsi_stmt (gsi));
 316               gimple_set_lhs (g, lhs);
 317               gsi_replace (&gsi, g, false);
 318             }
 319
 320           cfg_changed |= gimple_expand_vec_set_expr (fun, &gsi);
 321           if (gsi_end_p (gsi))
 322             break;
 323         }
 324     }
 325
 326   for (hash_map<tree, unsigned int>::iterator it = vec_cond_ssa_name_uses.begin ();
 327        it != vec_cond_ssa_name_uses.end (); ++it)
 328     bitmap_set_bit (dce_ssa_names, SSA_NAME_VERSION ((*it).first));
 329
 330   simple_dce_from_worklist (dce_ssa_names);
 331
 332   return cfg_changed ? TODO_cleanup_cfg : 0;
 333 }
 334
 335 namespace {
 336
 337 const pass_data pass_data_gimple_isel =
 338 {
 339   GIMPLE_PASS, /* type */
 340   "isel", /* name */
 341   OPTGROUP_VEC, /* optinfo_flags */
 342   TV_NONE, /* tv_id */
 343   PROP_cfg, /* properties_required */
 344   0, /* properties_provided */
 345   0, /* properties_destroyed */
 346   0, /* todo_flags_start */
 347   TODO_update_ssa, /* todo_flags_finish */
 348 };
 349
 350 class pass_gimple_isel : public gimple_opt_pass
 351 {
 352 public:
 353   pass_gimple_isel (gcc::context *ctxt)
 354     : gimple_opt_pass (pass_data_gimple_isel, ctxt)
 355   {}
 356
 357   /* opt_pass methods: */
 358   bool gate (function *) final override
 359     {
 360       return true;
 361     }
 362
 363   unsigned int execute (function *fun) final override
 364     {
 365       return gimple_expand_vec_exprs (fun);
 366     }
 367
 368 }; // class pass_gimple_isel
 369
 370 } // anon namespace
 371
 372 gimple_opt_pass *
 373 make_pass_gimple_isel (gcc::context *ctxt)
 374 {
 375   return new pass_gimple_isel (ctxt);
 376 }
 377