LCOV - code coverage report
Current view: top level - gcc - tree-ssa-phiprop.cc (source / functions) Coverage Total Hit
Test: gcc.info Lines: 96.8 % 218 211
Test Date: 2024-04-13 14:00:49 Functions: 100.0 % 8 8
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: - 0 0

             Branch data     Line data    Source code
       1                 :             : /* Backward propagation of indirect loads through PHIs.
       2                 :             :    Copyright (C) 2007-2024 Free Software Foundation, Inc.
       3                 :             :    Contributed by Richard Guenther <rguenther@suse.de>
       4                 :             : 
       5                 :             : This file is part of GCC.
       6                 :             : 
       7                 :             : GCC is free software; you can redistribute it and/or modify
       8                 :             : it under the terms of the GNU General Public License as published by
       9                 :             : the Free Software Foundation; either version 3, or (at your option)
      10                 :             : any later version.
      11                 :             : 
      12                 :             : GCC is distributed in the hope that it will be useful,
      13                 :             : but WITHOUT ANY WARRANTY; without even the implied warranty of
      14                 :             : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      15                 :             : GNU General Public License for more details.
      16                 :             : 
      17                 :             : You should have received a copy of the GNU General Public License
      18                 :             : along with GCC; see the file COPYING3.  If not see
      19                 :             : <http://www.gnu.org/licenses/>.  */
      20                 :             : 
      21                 :             : #include "config.h"
      22                 :             : #include "system.h"
      23                 :             : #include "coretypes.h"
      24                 :             : #include "backend.h"
      25                 :             : #include "tree.h"
      26                 :             : #include "gimple.h"
      27                 :             : #include "tree-pass.h"
      28                 :             : #include "ssa.h"
      29                 :             : #include "gimple-pretty-print.h"
      30                 :             : #include "fold-const.h"
      31                 :             : #include "tree-eh.h"
      32                 :             : #include "gimplify.h"
      33                 :             : #include "gimple-iterator.h"
      34                 :             : #include "stor-layout.h"
      35                 :             : #include "tree-ssa-loop.h"
      36                 :             : #include "tree-cfg.h"
      37                 :             : 
      38                 :             : /* This pass propagates indirect loads through the PHI node for its
      39                 :             :    address to make the load source possibly non-addressable and to
      40                 :             :    allow for PHI optimization to trigger.
      41                 :             : 
      42                 :             :    For example the pass changes
      43                 :             : 
      44                 :             :      # addr_1 = PHI <&a, &b>
      45                 :             :      tmp_1 = *addr_1;
      46                 :             : 
      47                 :             :    to
      48                 :             : 
      49                 :             :      # tmp_1 = PHI <a, b>
      50                 :             : 
      51                 :             :    but also handles more complex scenarios like
      52                 :             : 
      53                 :             :      D.2077_2 = &this_1(D)->a1;
      54                 :             :      ...
      55                 :             : 
      56                 :             :      # b_12 = PHI <&c(2), D.2077_2(3)>
      57                 :             :      D.2114_13 = *b_12;
      58                 :             :      ...
      59                 :             : 
      60                 :             :      # b_15 = PHI <b_12(4), &b(5)>
      61                 :             :      D.2080_5 = &this_1(D)->a0;
      62                 :             :      ...
      63                 :             : 
      64                 :             :      # b_18 = PHI <D.2080_5(6), &c(7)>
      65                 :             :      ...
      66                 :             : 
      67                 :             :      # b_21 = PHI <b_15(8), b_18(9)>
      68                 :             :      D.2076_8 = *b_21;
      69                 :             : 
      70                 :             :    where the addresses loaded are defined by PHIs itself.
      71                 :             :    The above happens for
      72                 :             : 
      73                 :             :      std::max(std::min(a0, c), std::min(std::max(a1, c), b))
      74                 :             : 
      75                 :             :    where this pass transforms it to a form later PHI optimization
      76                 :             :    recognizes and transforms it to the simple
      77                 :             : 
      78                 :             :      D.2109_10 = this_1(D)->a1;
      79                 :             :      D.2110_11 = c;
      80                 :             :      D.2114_31 = MAX_EXPR <D.2109_10, D.2110_11>;
      81                 :             :      D.2115_14 = b;
      82                 :             :      D.2125_17 = MIN_EXPR <D.2115_14, D.2114_31>;
      83                 :             :      D.2119_16 = this_1(D)->a0;
      84                 :             :      D.2124_32 = MIN_EXPR <D.2110_11, D.2119_16>;
      85                 :             :      D.2076_33 = MAX_EXPR <D.2125_17, D.2124_32>;
      86                 :             : 
      87                 :             :    The pass does a dominator walk processing loads using a basic-block
      88                 :             :    local analysis and stores the result for use by transformations on
      89                 :             :    dominated basic-blocks.  */
      90                 :             : 
      91                 :             : 
      92                 :             : /* Structure to keep track of the value of a dereferenced PHI result
      93                 :             :    and the virtual operand used for that dereference.  */
      94                 :             : 
      95                 :             : struct phiprop_d
      96                 :             : {
      97                 :             :   tree value;
      98                 :             :   tree vuse;
      99                 :             : };
     100                 :             : 
     101                 :             : /* Verify if the value recorded for NAME in PHIVN is still valid at
     102                 :             :    the start of basic block BB.  */
     103                 :             : 
     104                 :             : static bool
     105                 :          79 : phivn_valid_p (struct phiprop_d *phivn, tree name, basic_block bb)
     106                 :             : {
     107                 :          79 :   tree vuse = phivn[SSA_NAME_VERSION (name)].vuse;
     108                 :          79 :   gimple *use_stmt;
     109                 :          79 :   imm_use_iterator ui2;
     110                 :          79 :   bool ok = true;
     111                 :             : 
     112                 :             :   /* The def stmts of the virtual uses need to be dominated by bb.  */
     113                 :          79 :   gcc_assert (vuse != NULL_TREE);
     114                 :             : 
     115                 :         635 :   FOR_EACH_IMM_USE_STMT (use_stmt, ui2, vuse)
     116                 :             :     {
     117                 :             :       /* If BB does not dominate a VDEF, the value is invalid.  */
     118                 :         577 :       if ((gimple_vdef (use_stmt) != NULL_TREE
     119                 :         507 :            || gimple_code (use_stmt) == GIMPLE_PHI)
     120                 :         577 :           && !dominated_by_p (CDI_DOMINATORS, gimple_bb (use_stmt), bb))
     121                 :             :         {
     122                 :             :           ok = false;
     123                 :             :           break;
     124                 :             :         }
     125                 :          79 :     }
     126                 :             : 
     127                 :          79 :   return ok;
     128                 :             : }
     129                 :             : 
     130                 :             : /* Insert a new phi node for the dereference of PHI at basic_block
     131                 :             :    BB with the virtual operands from USE_STMT.  */
     132                 :             : 
     133                 :             : static tree
     134                 :       10593 : phiprop_insert_phi (basic_block bb, gphi *phi, gimple *use_stmt,
     135                 :             :                     struct phiprop_d *phivn, size_t n)
     136                 :             : {
     137                 :       10593 :   tree res;
     138                 :       10593 :   gphi *new_phi = NULL;
     139                 :       10593 :   edge_iterator ei;
     140                 :       10593 :   edge e;
     141                 :             : 
     142                 :       10593 :   gcc_assert (is_gimple_assign (use_stmt)
     143                 :             :               && gimple_assign_rhs_code (use_stmt) == MEM_REF);
     144                 :             : 
     145                 :             :   /* Build a new PHI node to replace the definition of
     146                 :             :      the indirect reference lhs.  */
     147                 :       10593 :   res = gimple_assign_lhs (use_stmt);
     148                 :       10593 :   if (TREE_CODE (res) == SSA_NAME)
     149                 :       10538 :     new_phi = create_phi_node (res, bb);
     150                 :             : 
     151                 :       10593 :   if (dump_file && (dump_flags & TDF_DETAILS))
     152                 :             :     {
     153                 :           2 :       fprintf (dump_file, "Inserting PHI for result of load ");
     154                 :           2 :       print_gimple_stmt (dump_file, use_stmt, 0);
     155                 :             :     }
     156                 :             : 
     157                 :       10593 :   gphi *vphi = get_virtual_phi (bb);
     158                 :             : 
     159                 :             :   /* Add PHI arguments for each edge inserting loads of the
     160                 :             :      addressable operands.  */
     161                 :       30241 :   FOR_EACH_EDGE (e, ei, bb->preds)
     162                 :             :     {
     163                 :       19648 :       tree old_arg, new_var;
     164                 :       19648 :       gassign *tmp;
     165                 :       19648 :       location_t locus;
     166                 :             : 
     167                 :       19648 :       old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
     168                 :       19648 :       locus = gimple_phi_arg_location_from_edge (phi, e);
     169                 :       19648 :       while (TREE_CODE (old_arg) == SSA_NAME
     170                 :       20714 :              && (SSA_NAME_VERSION (old_arg) >= n
     171                 :        1124 :                  || phivn[SSA_NAME_VERSION (old_arg)].value == NULL_TREE))
     172                 :             :         {
     173                 :        1066 :           gimple *def_stmt = SSA_NAME_DEF_STMT (old_arg);
     174                 :        1066 :           old_arg = gimple_assign_rhs1 (def_stmt);
     175                 :        1066 :           locus = gimple_location (def_stmt);
     176                 :             :         }
     177                 :             : 
     178                 :       19648 :       if (TREE_CODE (old_arg) == SSA_NAME)
     179                 :             :         {
     180                 :          58 :           if (dump_file && (dump_flags & TDF_DETAILS))
     181                 :             :             {
     182                 :           0 :               fprintf (dump_file, "  for edge defining ");
     183                 :           0 :               print_generic_expr (dump_file, PHI_ARG_DEF_FROM_EDGE (phi, e));
     184                 :           0 :               fprintf (dump_file, " reusing PHI result ");
     185                 :           0 :               print_generic_expr (dump_file,
     186                 :           0 :                                   phivn[SSA_NAME_VERSION (old_arg)].value);
     187                 :           0 :               fprintf (dump_file, "\n");
     188                 :             :             }
     189                 :             :           /* Reuse a formerly created dereference.  */
     190                 :          58 :           new_var = phivn[SSA_NAME_VERSION (old_arg)].value;
     191                 :             :         }
     192                 :             :       else
     193                 :             :         {
     194                 :       19590 :           tree rhs = gimple_assign_rhs1 (use_stmt);
     195                 :       19590 :           gcc_assert (TREE_CODE (old_arg) == ADDR_EXPR);
     196                 :       19590 :           tree vuse = NULL_TREE;
     197                 :       19590 :           if (TREE_CODE (res) == SSA_NAME)
     198                 :             :             {
     199                 :       19480 :               new_var = make_ssa_name (TREE_TYPE (rhs));
     200                 :       19480 :               if (vphi)
     201                 :           0 :                 vuse = PHI_ARG_DEF_FROM_EDGE (vphi, e);
     202                 :             :               else
     203                 :       19480 :                 vuse = gimple_vuse (use_stmt);
     204                 :             :             }
     205                 :             :           else
     206                 :             :             /* For the aggregate copy case updating virtual operands
     207                 :             :                we'd have to possibly insert a virtual PHI and we have
     208                 :             :                to split the existing VUSE lifetime.  Leave that to
     209                 :             :                the generic SSA updating.  */
     210                 :         110 :             new_var = unshare_expr (res);
     211                 :       19590 :           if (!is_gimple_min_invariant (old_arg))
     212                 :        1050 :             old_arg = PHI_ARG_DEF_FROM_EDGE (phi, e);
     213                 :             :           else
     214                 :       18540 :             old_arg = unshare_expr (old_arg);
     215                 :       19590 :           tmp = gimple_build_assign (new_var,
     216                 :       19590 :                                      fold_build2 (MEM_REF, TREE_TYPE (rhs),
     217                 :             :                                                   old_arg,
     218                 :             :                                                   TREE_OPERAND (rhs, 1)));
     219                 :       19590 :           gimple_set_location (tmp, locus);
     220                 :       19590 :           if (vuse)
     221                 :       19480 :             gimple_set_vuse (tmp, vuse);
     222                 :             : 
     223                 :       19590 :           gsi_insert_on_edge (e, tmp);
     224                 :       19590 :           update_stmt (tmp);
     225                 :             : 
     226                 :       19590 :           if (dump_file && (dump_flags & TDF_DETAILS))
     227                 :             :             {
     228                 :           4 :               fprintf (dump_file, "  for edge defining ");
     229                 :           4 :               print_generic_expr (dump_file, PHI_ARG_DEF_FROM_EDGE (phi, e));
     230                 :           4 :               fprintf (dump_file, " inserting load ");
     231                 :           4 :               print_gimple_stmt (dump_file, tmp, 0);
     232                 :             :             }
     233                 :             :         }
     234                 :             : 
     235                 :       19648 :       if (new_phi)
     236                 :       19538 :         add_phi_arg (new_phi, new_var, e, locus);
     237                 :             :     }
     238                 :             : 
     239                 :       10593 :   if (new_phi)
     240                 :             :     {
     241                 :       10538 :       update_stmt (new_phi);
     242                 :             : 
     243                 :       10538 :       if (dump_file && (dump_flags & TDF_DETAILS))
     244                 :           2 :         print_gimple_stmt (dump_file, new_phi, 0);
     245                 :             :     }
     246                 :             : 
     247                 :       10593 :   return res;
     248                 :             : }
     249                 :             : 
     250                 :             : /* Verify if *idx is available at *DATA.  */
     251                 :             : 
     252                 :             : static bool
     253                 :          42 : chk_uses (tree, tree *idx, void *data)
     254                 :             : {
     255                 :          42 :   basic_block dom = (basic_block) data;
     256                 :          42 :   if (TREE_CODE (*idx) == SSA_NAME)
     257                 :          30 :     return (SSA_NAME_IS_DEFAULT_DEF (*idx)
     258                 :          30 :             || ! dominated_by_p (CDI_DOMINATORS,
     259                 :          18 :                                  gimple_bb (SSA_NAME_DEF_STMT (*idx)), dom));
     260                 :             :   return true;
     261                 :             : }
     262                 :             : 
     263                 :             : /* Propagate between the phi node arguments of PHI in BB and phi result
     264                 :             :    users.  For now this matches
     265                 :             :         # p_2 = PHI <&x, &y>
     266                 :             :       <Lx>:;
     267                 :             :         p_3 = p_2;
     268                 :             :         z_2 = *p_3;
     269                 :             :    and converts it to
     270                 :             :         # z_2 = PHI <x, y>
     271                 :             :       <Lx>:;
     272                 :             :    Returns true if a transformation was done and edge insertions
     273                 :             :    need to be committed.  Global data PHIVN and N is used to track
     274                 :             :    past transformation results.  We need to be especially careful here
     275                 :             :    with aliasing issues as we are moving memory reads.  */
     276                 :             : 
     277                 :             : static bool
     278                 :     7052665 : propagate_with_phi (basic_block bb, gphi *phi, struct phiprop_d *phivn,
     279                 :             :                     size_t n)
     280                 :             : {
     281                 :     7052665 :   tree ptr = PHI_RESULT (phi);
     282                 :     7052665 :   gimple *use_stmt;
     283                 :     7052665 :   tree res = NULL_TREE;
     284                 :     7052665 :   gimple_stmt_iterator gsi;
     285                 :     7052665 :   imm_use_iterator ui;
     286                 :     7052665 :   use_operand_p arg_p, use;
     287                 :     7052665 :   ssa_op_iter i;
     288                 :     7052665 :   bool phi_inserted;
     289                 :     7052665 :   bool changed;
     290                 :     7052665 :   tree type = NULL_TREE;
     291                 :             : 
     292                 :    13461123 :   if (!POINTER_TYPE_P (TREE_TYPE (ptr))
     293                 :     7070994 :       || (!is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr)))
     294                 :      310724 :           && TYPE_MODE (TREE_TYPE (TREE_TYPE (ptr))) == BLKmode))
     295                 :     6620222 :     return false;
     296                 :             : 
     297                 :             :   /* Check if we can "cheaply" dereference all phi arguments.  */
     298                 :      535810 :   FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
     299                 :             :     {
     300                 :      508391 :       tree arg = USE_FROM_PTR (arg_p);
     301                 :             :       /* Walk the ssa chain until we reach a ssa name we already
     302                 :             :          created a value for or we reach a definition of the form
     303                 :             :          ssa_name_n = &var;  */
     304                 :      508391 :       while (TREE_CODE (arg) == SSA_NAME
     305                 :      429589 :              && !SSA_NAME_IS_DEFAULT_DEF (arg)
     306                 :     1079542 :              && (SSA_NAME_VERSION (arg) >= n
     307                 :      379451 :                  || phivn[SSA_NAME_VERSION (arg)].value == NULL_TREE))
     308                 :             :         {
     309                 :      379382 :           gimple *def_stmt = SSA_NAME_DEF_STMT (arg);
     310                 :      379382 :           if (!gimple_assign_single_p (def_stmt))
     311                 :             :             return false;
     312                 :      191690 :           arg = gimple_assign_rhs1 (def_stmt);
     313                 :             :         }
     314                 :      320699 :       if (TREE_CODE (arg) != ADDR_EXPR
     315                 :      320778 :           && !(TREE_CODE (arg) == SSA_NAME
     316                 :       50207 :                && SSA_NAME_VERSION (arg) < n
     317                 :       50207 :                && phivn[SSA_NAME_VERSION (arg)].value != NULL_TREE
     318                 :          79 :                && (!type
     319                 :           4 :                    || types_compatible_p
     320                 :           4 :                        (type, TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value)))
     321                 :          79 :                && phivn_valid_p (phivn, arg, bb)))
     322                 :      217332 :         return false;
     323                 :      103367 :       if (!type
     324                 :      103326 :           && TREE_CODE (arg) == SSA_NAME)
     325                 :          54 :         type = TREE_TYPE (phivn[SSA_NAME_VERSION (arg)].value);
     326                 :             :     }
     327                 :             : 
     328                 :             :   /* Find a dereferencing use.  First follow (single use) ssa
     329                 :             :      copy chains for ptr.  */
     330                 :       28449 :   while (single_imm_use (ptr, &use, &use_stmt)
     331                 :       28449 :          && gimple_assign_ssa_name_copy_p (use_stmt))
     332                 :        1030 :     ptr = gimple_assign_lhs (use_stmt);
     333                 :             : 
     334                 :             :   /* Replace the first dereference of *ptr if there is one and if we
     335                 :             :      can move the loads to the place of the ptr phi node.  */
     336                 :       27419 :   phi_inserted = false;
     337                 :       27419 :   changed = false;
     338                 :       66555 :   FOR_EACH_IMM_USE_STMT (use_stmt, ui, ptr)
     339                 :             :     {
     340                 :       39136 :       gimple *def_stmt;
     341                 :       39136 :       tree vuse;
     342                 :             : 
     343                 :       39136 :       if (!dom_info_available_p (cfun, CDI_POST_DOMINATORS))
     344                 :       16777 :         calculate_dominance_info (CDI_POST_DOMINATORS);
     345                 :             : 
     346                 :             :       /* Only replace loads in blocks that post-dominate the PHI node.  That
     347                 :             :          makes sure we don't end up speculating loads.  */
     348                 :       39136 :       if (!dominated_by_p (CDI_POST_DOMINATORS,
     349                 :       39136 :                            bb, gimple_bb (use_stmt)))
     350                 :        5687 :         continue;
     351                 :             : 
     352                 :             :       /* Check whether this is a load of *ptr.  */
     353                 :       33449 :       if (!(is_gimple_assign (use_stmt)
     354                 :       14525 :             && gimple_assign_rhs_code (use_stmt) == MEM_REF
     355                 :       11018 :             && TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0) == ptr
     356                 :       11018 :             && integer_zerop (TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 1))
     357                 :       11014 :             && (!type
     358                 :          66 :                 || types_compatible_p
     359                 :          66 :                      (TREE_TYPE (gimple_assign_lhs (use_stmt)), type))
     360                 :             :             /* We cannot replace a load that may throw or is volatile.
     361                 :             :                For volatiles the transform can change the number of
     362                 :             :                executions if the load is inside a loop but the address
     363                 :             :                computations outside (PR91812).  We could relax this
     364                 :             :                if we guard against that appropriately.  For loads that can
     365                 :             :                throw we could relax things if the moved loads all are
     366                 :             :                known to not throw.  */
     367                 :       11014 :             && !stmt_can_throw_internal (cfun, use_stmt)
     368                 :       21982 :             && !gimple_has_volatile_ops (use_stmt)))
     369                 :       22467 :         continue;
     370                 :             : 
     371                 :             :       /* Check if we can move the loads.  The def stmt of the virtual use
     372                 :             :          needs to be in a different basic block dominating bb.  When the
     373                 :             :          def is an edge-inserted one we know it dominates us.  */
     374                 :       10982 :       vuse = gimple_vuse (use_stmt);
     375                 :       10982 :       def_stmt = SSA_NAME_DEF_STMT (vuse);
     376                 :       10982 :       if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
     377                 :       10982 :           && (gimple_bb (def_stmt) == bb
     378                 :        9723 :               || (gimple_bb (def_stmt)
     379                 :        9723 :                   && !dominated_by_p (CDI_DOMINATORS,
     380                 :        9723 :                                       bb, gimple_bb (def_stmt)))))
     381                 :         347 :         goto next;
     382                 :             : 
     383                 :             :       /* Found a proper dereference with an aggregate copy.  Just
     384                 :             :          insert aggregate copies on the edges instead.  */
     385                 :       10635 :       if (!is_gimple_reg_type (TREE_TYPE (gimple_assign_lhs (use_stmt))))
     386                 :             :         {
     387                 :         170 :           if (!gimple_vdef (use_stmt))
     388                 :          30 :             goto next;
     389                 :             : 
     390                 :             :           /* As we replicate the lhs on each incoming edge all
     391                 :             :              used SSA names have to be available there.  */
     392                 :          85 :           if (! for_each_index (gimple_assign_lhs_ptr (use_stmt),
     393                 :             :                                 chk_uses,
     394                 :          85 :                                 get_immediate_dominator (CDI_DOMINATORS,
     395                 :             :                                                          gimple_bb (phi))))
     396                 :          18 :             goto next;
     397                 :             : 
     398                 :          67 :           gimple *vuse_stmt;
     399                 :          67 :           imm_use_iterator vui;
     400                 :          67 :           use_operand_p vuse_p;
     401                 :             :           /* In order to move the aggregate copies earlier, make sure
     402                 :             :              there are no statements that could read from memory
     403                 :             :              aliasing the lhs in between the start of bb and use_stmt.
     404                 :             :              As we require use_stmt to have a VDEF above, loads after
     405                 :             :              use_stmt will use a different virtual SSA_NAME.  When
     406                 :             :              we reach an edge inserted load the constraints we place
     407                 :             :              on processing guarantees that program order is preserved
     408                 :             :              so we can avoid checking those.  */
     409                 :         345 :           FOR_EACH_IMM_USE_FAST (vuse_p, vui, vuse)
     410                 :             :             {
     411                 :         290 :               vuse_stmt = USE_STMT (vuse_p);
     412                 :         290 :               if (vuse_stmt == use_stmt)
     413                 :          62 :                 continue;
     414                 :         228 :               if (!gimple_bb (vuse_stmt)
     415                 :         424 :                   || !dominated_by_p (CDI_DOMINATORS,
     416                 :         196 :                                       gimple_bb (vuse_stmt), bb))
     417                 :         216 :                 continue;
     418                 :          12 :               if (ref_maybe_used_by_stmt_p (vuse_stmt,
     419                 :             :                                             gimple_assign_lhs (use_stmt)))
     420                 :          12 :                 goto next;
     421                 :             :             }
     422                 :             : 
     423                 :          55 :           phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
     424                 :             : 
     425                 :             :           /* Remove old stmt.  The phi is taken care of by DCE.  */
     426                 :          55 :           gsi = gsi_for_stmt (use_stmt);
     427                 :             :           /* Unlinking the VDEF here is fine as we are sure that we process
     428                 :             :              stmts in execution order due to aggregate copies having VDEFs
     429                 :             :              and we emit loads on the edges in the very same order.
     430                 :             :              We get multiple copies (or intermediate register loads) handled
     431                 :             :              only by walking PHIs or immediate uses in a lucky order though,
     432                 :             :              so we could signal the caller to re-start iterating over PHIs
     433                 :             :              when we come here which would make it quadratic in the number
     434                 :             :              of PHIs.  */
     435                 :          55 :           unlink_stmt_vdef (use_stmt);
     436                 :          55 :           gsi_remove (&gsi, true);
     437                 :             : 
     438                 :          55 :           changed = true;
     439                 :             :         }
     440                 :             : 
     441                 :             :       /* Found a proper dereference.  Insert a phi node if this
     442                 :             :          is the first load transformation.  */
     443                 :       10550 :       else if (!phi_inserted)
     444                 :             :         {
     445                 :       10538 :           res = phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
     446                 :       10538 :           type = TREE_TYPE (res);
     447                 :             : 
     448                 :             :           /* Remember the value we created for *ptr.  */
     449                 :       10538 :           phivn[SSA_NAME_VERSION (ptr)].value = res;
     450                 :       10538 :           phivn[SSA_NAME_VERSION (ptr)].vuse = vuse;
     451                 :             : 
     452                 :             :           /* Remove old stmt.  The phi is taken care of by DCE, if we
     453                 :             :              want to delete it here we also have to delete all intermediate
     454                 :             :              copies.  */
     455                 :       10538 :           gsi = gsi_for_stmt (use_stmt);
     456                 :       10538 :           gsi_remove (&gsi, true);
     457                 :             : 
     458                 :       10538 :           phi_inserted = true;
     459                 :       10538 :           changed = true;
     460                 :             :         }
     461                 :             :       else
     462                 :             :         {
     463                 :             :           /* Further replacements are easy, just make a copy out of the
     464                 :             :              load.  */
     465                 :          12 :           gimple_assign_set_rhs1 (use_stmt, res);
     466                 :          12 :           update_stmt (use_stmt);
     467                 :          12 :           changed = true;
     468                 :             :         }
     469                 :             : 
     470                 :       39136 : next:;
     471                 :             :       /* Continue searching for a proper dereference.  */
     472                 :       27419 :     }
     473                 :             : 
     474                 :       27419 :   return changed;
     475                 :             : }
     476                 :             : 
     477                 :             : /* Main entry for phiprop pass.  */
     478                 :             : 
     479                 :             : namespace {
     480                 :             : 
     481                 :             : const pass_data pass_data_phiprop =
     482                 :             : {
     483                 :             :   GIMPLE_PASS, /* type */
     484                 :             :   "phiprop", /* name */
     485                 :             :   OPTGROUP_NONE, /* optinfo_flags */
     486                 :             :   TV_TREE_PHIPROP, /* tv_id */
     487                 :             :   ( PROP_cfg | PROP_ssa ), /* properties_required */
     488                 :             :   0, /* properties_provided */
     489                 :             :   0, /* properties_destroyed */
     490                 :             :   0, /* todo_flags_start */
     491                 :             :   0, /* todo_flags_finish */
     492                 :             : };
     493                 :             : 
     494                 :             : class pass_phiprop : public gimple_opt_pass
     495                 :             : {
     496                 :             : public:
     497                 :      560910 :   pass_phiprop (gcc::context *ctxt)
     498                 :     1121820 :     : gimple_opt_pass (pass_data_phiprop, ctxt)
     499                 :             :   {}
     500                 :             : 
     501                 :             :   /* opt_pass methods: */
     502                 :      280455 :   opt_pass * clone () final override { return new pass_phiprop (m_ctxt); }
     503                 :     3128991 :   bool gate (function *) final override { return flag_tree_phiprop; }
     504                 :             :   unsigned int execute (function *) final override;
     505                 :             : 
     506                 :             : }; // class pass_phiprop
     507                 :             : 
     508                 :             : unsigned int
     509                 :     3128846 : pass_phiprop::execute (function *fun)
     510                 :             : {
     511                 :     3128846 :   struct phiprop_d *phivn;
     512                 :     3128846 :   bool did_something = false;
     513                 :     3128846 :   basic_block bb;
     514                 :     3128846 :   gphi_iterator gsi;
     515                 :     3128846 :   unsigned i;
     516                 :     3128846 :   size_t n;
     517                 :             : 
     518                 :     3128846 :   calculate_dominance_info (CDI_DOMINATORS);
     519                 :             : 
     520                 :     3128846 :   n = num_ssa_names;
     521                 :     3128846 :   phivn = XCNEWVEC (struct phiprop_d, n);
     522                 :             : 
     523                 :             :   /* Walk the dominator tree in preorder.  */
     524                 :     3128846 :   auto_vec<basic_block> bbs
     525                 :             :   = get_all_dominated_blocks (CDI_DOMINATORS,
     526                 :     3128846 :                               single_succ (ENTRY_BLOCK_PTR_FOR_FN (fun)));
     527                 :    28148365 :   FOR_EACH_VEC_ELT (bbs, i, bb)
     528                 :             :     {
     529                 :             :       /* Since we're going to move dereferences across predecessor
     530                 :             :          edges avoid blocks with abnormal predecessors.  */
     531                 :    21890673 :       if (bb_has_abnormal_pred (bb))
     532                 :        8146 :         continue;
     533                 :    28935192 :       for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
     534                 :     7052665 :         did_something |= propagate_with_phi (bb, gsi.phi (), phivn, n);
     535                 :             :     }
     536                 :             : 
     537                 :     3128846 :   if (did_something)
     538                 :        8350 :     gsi_commit_edge_inserts ();
     539                 :             : 
     540                 :     3128846 :   free (phivn);
     541                 :             : 
     542                 :     3128846 :   free_dominance_info (CDI_POST_DOMINATORS);
     543                 :             : 
     544                 :     6249342 :   return did_something ? TODO_update_ssa_only_virtuals : 0;
     545                 :     3128846 : }
     546                 :             : 
     547                 :             : } // anon namespace
     548                 :             : 
     549                 :             : gimple_opt_pass *
     550                 :      280455 : make_pass_phiprop (gcc::context *ctxt)
     551                 :             : {
     552                 :      280455 :   return new pass_phiprop (ctxt);
     553                 :             : }
        

Generated by: LCOV version 2.1-beta

LCOV profile is generated on x86_64 machine using following configure options: configure --disable-bootstrap --enable-coverage=opt --enable-languages=c,c++,fortran,go,jit,lto,rust,m2 --enable-host-shared. GCC test suite is run with the built compiler.