gcc/gimple-isel.cc

   1 /* Schedule GIMPLE vector statements.
   2    Copyright (C) 2020 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
  41 /* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to
  42    internal function based on vector type of selected expansion.
  43    i.e.:
  44      VIEW_CONVERT_EXPR<int[4]>(u)[_1] =  = i_4(D);
  45    =>
  46      _7 = u;
  47      _8 = .VEC_SET (_7, i_4(D), _1);
  48      u = _8;  */
  49
  50 static gimple *
  51 gimple_expand_vec_set_expr (gimple_stmt_iterator *gsi)
  52 {
  53   enum tree_code code;
  54   gcall *new_stmt = NULL;
  55   gassign *ass_stmt = NULL;
  56
  57   /* Only consider code == GIMPLE_ASSIGN.  */
  58   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
  59   if (!stmt)
  60     return NULL;
  61
  62   tree lhs = gimple_assign_lhs (stmt);
  63   code = TREE_CODE (lhs);
  64   if (code != ARRAY_REF)
  65     return NULL;
  66
  67   tree val = gimple_assign_rhs1 (stmt);
  68   tree op0 = TREE_OPERAND (lhs, 0);
  69   if (TREE_CODE (op0) == VIEW_CONVERT_EXPR && DECL_P (TREE_OPERAND (op0, 0))
  70       && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))
  71       && TYPE_MODE (TREE_TYPE (lhs))
  72            == TYPE_MODE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (op0, 0)))))
  73     {
  74       tree pos = TREE_OPERAND (lhs, 1);
  75       tree view_op0 = TREE_OPERAND (op0, 0);
  76       machine_mode outermode = TYPE_MODE (TREE_TYPE (view_op0));
  77       if (auto_var_in_fn_p (view_op0, cfun->decl)
  78           && !TREE_ADDRESSABLE (view_op0) && can_vec_set_var_idx_p (outermode))
  79         {
  80           location_t loc = gimple_location (stmt);
  81           tree var_src = make_ssa_name (TREE_TYPE (view_op0));
  82           tree var_dst = make_ssa_name (TREE_TYPE (view_op0));
  83
  84           ass_stmt = gimple_build_assign (var_src, view_op0);
  85           gimple_set_vuse (ass_stmt, gimple_vuse (stmt));
  86           gimple_set_location (ass_stmt, loc);
  87           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
  88
  89           new_stmt
  90             = gimple_build_call_internal (IFN_VEC_SET, 3, var_src, val, pos);
  91           gimple_call_set_lhs (new_stmt, var_dst);
  92           gimple_set_location (new_stmt, loc);
  93           gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
  94
  95           ass_stmt = gimple_build_assign (view_op0, var_dst);
  96           gimple_set_location (ass_stmt, loc);
  97           gsi_insert_before (gsi, ass_stmt, GSI_SAME_STMT);
  98
  99           gimple_move_vops (ass_stmt, stmt);
 100           gsi_remove (gsi, true);
 101         }
 102     }
 103
 104   return ass_stmt;
 105 }
 106
 107 /* Expand all VEC_COND_EXPR gimple assignments into calls to internal
 108    function based on type of selected expansion.  */
 109
 110 static gimple *
 111 gimple_expand_vec_cond_expr (gimple_stmt_iterator *gsi,
 112                              hash_map<tree, unsigned int> *vec_cond_ssa_name_uses)
 113 {
 114   tree lhs, op0a = NULL_TREE, op0b = NULL_TREE;
 115   enum tree_code code;
 116   enum tree_code tcode;
 117   machine_mode cmp_op_mode;
 118   bool unsignedp;
 119   enum insn_code icode;
 120   imm_use_iterator imm_iter;
 121
 122   /* Only consider code == GIMPLE_ASSIGN.  */
 123   gassign *stmt = dyn_cast<gassign *> (gsi_stmt (*gsi));
 124   if (!stmt)
 125     return NULL;
 126
 127   code = gimple_assign_rhs_code (stmt);
 128   if (code != VEC_COND_EXPR)
 129     return NULL;
 130
 131   tree op0 = gimple_assign_rhs1 (stmt);
 132   tree op1 = gimple_assign_rhs2 (stmt);
 133   tree op2 = gimple_assign_rhs3 (stmt);
 134   lhs = gimple_assign_lhs (stmt);
 135   machine_mode mode = TYPE_MODE (TREE_TYPE (lhs));
 136
 137   gcc_assert (!COMPARISON_CLASS_P (op0));
 138   if (TREE_CODE (op0) == SSA_NAME)
 139     {
 140       unsigned int used_vec_cond_exprs = 0;
 141       unsigned int *slot = vec_cond_ssa_name_uses->get (op0);
 142       if (slot)
 143         used_vec_cond_exprs = *slot;
 144       else
 145         {
 146           gimple *use_stmt;
 147           FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, op0)
 148             {
 149               gassign *assign = dyn_cast<gassign *> (use_stmt);
 150               if (assign != NULL
 151                   && gimple_assign_rhs_code (assign) == VEC_COND_EXPR
 152                   && gimple_assign_rhs1 (assign) == op0)
 153                 used_vec_cond_exprs++;
 154             }
 155           vec_cond_ssa_name_uses->put (op0, used_vec_cond_exprs);
 156         }
 157
 158       gassign *def_stmt = dyn_cast<gassign *> (SSA_NAME_DEF_STMT (op0));
 159       if (def_stmt)
 160         {
 161           tcode = gimple_assign_rhs_code (def_stmt);
 162           op0a = gimple_assign_rhs1 (def_stmt);
 163           op0b = gimple_assign_rhs2 (def_stmt);
 164
 165           tree op0_type = TREE_TYPE (op0);
 166           tree op0a_type = TREE_TYPE (op0a);
 167           if (used_vec_cond_exprs >= 2
 168               && (get_vcond_mask_icode (mode, TYPE_MODE (op0_type))
 169                   != CODE_FOR_nothing)
 170               && expand_vec_cmp_expr_p (op0a_type, op0_type, tcode))
 171             {
 172               /* Keep the SSA name and use vcond_mask.  */
 173               tcode = TREE_CODE (op0);
 174             }
 175         }
 176       else
 177         tcode = TREE_CODE (op0);
 178     }
 179   else
 180     tcode = TREE_CODE (op0);
 181
 182   if (TREE_CODE_CLASS (tcode) != tcc_comparison)
 183     {
 184       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0)));
 185       if (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
 186           != CODE_FOR_nothing)
 187         return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
 188       /* Fake op0 < 0.  */
 189       else
 190         {
 191           gcc_assert (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (op0)))
 192                       == MODE_VECTOR_INT);
 193           op0a = op0;
 194           op0b = build_zero_cst (TREE_TYPE (op0));
 195           tcode = LT_EXPR;
 196         }
 197     }
 198   cmp_op_mode = TYPE_MODE (TREE_TYPE (op0a));
 199   unsignedp = TYPE_UNSIGNED (TREE_TYPE (op0a));
 200
 201
 202   gcc_assert (known_eq (GET_MODE_NUNITS (mode),
 203                         GET_MODE_NUNITS (cmp_op_mode)));
 204
 205   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
 206   if (icode == CODE_FOR_nothing)
 207     {
 208       if (tcode == LT_EXPR
 209           && op0a == op0)
 210         {
 211           /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
 212              into a constant when only get_vcond_eq_icode is supported.
 213              Try changing it to NE_EXPR.  */
 214           tcode = NE_EXPR;
 215         }
 216       if (tcode == EQ_EXPR || tcode == NE_EXPR)
 217         {
 218           tree tcode_tree = build_int_cst (integer_type_node, tcode);
 219           return gimple_build_call_internal (IFN_VCONDEQ, 5, op0a, op0b, op1,
 220                                              op2, tcode_tree);
 221         }
 222     }
 223
 224   gcc_assert (icode != CODE_FOR_nothing);
 225   tree tcode_tree = build_int_cst (integer_type_node, tcode);
 226   return gimple_build_call_internal (unsignedp ? IFN_VCONDU : IFN_VCOND,
 227                                      5, op0a, op0b, op1, op2, tcode_tree);
 228 }
 229
 230
 231
 232 /* Iterate all gimple statements and try to expand
 233    VEC_COND_EXPR assignments.  */
 234
 235 static unsigned int
 236 gimple_expand_vec_exprs (void)
 237 {
 238   gimple_stmt_iterator gsi;
 239   basic_block bb;
 240   hash_map<tree, unsigned int> vec_cond_ssa_name_uses;
 241   auto_bitmap dce_ssa_names;
 242
 243   FOR_EACH_BB_FN (bb, cfun)
 244     {
 245       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 246         {
 247           gimple *g = gimple_expand_vec_cond_expr (&gsi,
 248                                                    &vec_cond_ssa_name_uses);
 249
 250           if (g != NULL)
 251             {
 252               tree lhs = gimple_assign_lhs (gsi_stmt (gsi));
 253               gimple_set_lhs (g, lhs);
 254               gsi_replace (&gsi, g, false);
 255             }
 256
 257           gimple_expand_vec_set_expr (&gsi);
 258         }
 259     }
 260
 261   for (hash_map<tree, unsigned int>::iterator it = vec_cond_ssa_name_uses.begin ();
 262        it != vec_cond_ssa_name_uses.end (); ++it)
 263     bitmap_set_bit (dce_ssa_names, SSA_NAME_VERSION ((*it).first));
 264
 265   simple_dce_from_worklist (dce_ssa_names);
 266
 267   return 0;
 268 }
 269
 270 namespace {
 271
 272 const pass_data pass_data_gimple_isel =
 273 {
 274   GIMPLE_PASS, /* type */
 275   "isel", /* name */
 276   OPTGROUP_VEC, /* optinfo_flags */
 277   TV_NONE, /* tv_id */
 278   PROP_cfg, /* properties_required */
 279   0, /* properties_provided */
 280   0, /* properties_destroyed */
 281   0, /* todo_flags_start */
 282   TODO_update_ssa, /* todo_flags_finish */
 283 };
 284
 285 class pass_gimple_isel : public gimple_opt_pass
 286 {
 287 public:
 288   pass_gimple_isel (gcc::context *ctxt)
 289     : gimple_opt_pass (pass_data_gimple_isel, ctxt)
 290   {}
 291
 292   /* opt_pass methods: */
 293   virtual bool gate (function *)
 294     {
 295       return true;
 296     }
 297
 298   virtual unsigned int execute (function *)
 299     {
 300       return gimple_expand_vec_exprs ();
 301     }
 302
 303 }; // class pass_gimple_isel
 304
 305 } // anon namespace
 306
 307 gimple_opt_pass *
 308 make_pass_gimple_isel (gcc::context *ctxt)
 309 {
 310   return new pass_gimple_isel (ctxt);
 311 }
 312