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Diffstat (limited to 'gcc/tree-ssa-copyrename.c')
| -rw-r--r-- | gcc/tree-ssa-copyrename.c | 475 |
1 files changed, 0 insertions, 475 deletions
diff --git a/gcc/tree-ssa-copyrename.c b/gcc/tree-ssa-copyrename.c deleted file mode 100644 index aeb7f28..0000000 --- a/gcc/tree-ssa-copyrename.c +++ /dev/null @@ -1,475 +0,0 @@ -/* Rename SSA copies. - Copyright (C) 2004-2015 Free Software Foundation, Inc. - Contributed by Andrew MacLeod <amacleod@redhat.com> - -This file is part of GCC. - -GCC is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 3, or (at your option) -any later version. - -GCC is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with GCC; see the file COPYING3. If not see -<http://www.gnu.org/licenses/>. */ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "backend.h" -#include "tree.h" -#include "gimple.h" -#include "rtl.h" -#include "ssa.h" -#include "alias.h" -#include "fold-const.h" -#include "internal-fn.h" -#include "gimple-iterator.h" -#include "flags.h" -#include "tree-pretty-print.h" -#include "insn-config.h" -#include "expmed.h" -#include "dojump.h" -#include "explow.h" -#include "calls.h" -#include "emit-rtl.h" -#include "varasm.h" -#include "stmt.h" -#include "expr.h" -#include "tree-dfa.h" -#include "tree-inline.h" -#include "tree-ssa-live.h" -#include "tree-pass.h" -#include "langhooks.h" - -static struct -{ - /* Number of copies coalesced. */ - int coalesced; -} stats; - -/* The following routines implement the SSA copy renaming phase. - - This optimization looks for copies between 2 SSA_NAMES, either through a - direct copy, or an implicit one via a PHI node result and its arguments. - - Each copy is examined to determine if it is possible to rename the base - variable of one of the operands to the same variable as the other operand. - i.e. - T.3_5 = <blah> - a_1 = T.3_5 - - If this copy couldn't be copy propagated, it could possibly remain in the - program throughout the optimization phases. After SSA->normal, it would - become: - - T.3 = <blah> - a = T.3 - - Since T.3_5 is distinct from all other SSA versions of T.3, there is no - fundamental reason why the base variable needs to be T.3, subject to - certain restrictions. This optimization attempts to determine if we can - change the base variable on copies like this, and result in code such as: - - a_5 = <blah> - a_1 = a_5 - - This gives the SSA->normal pass a shot at coalescing a_1 and a_5. If it is - possible, the copy goes away completely. If it isn't possible, a new temp - will be created for a_5, and you will end up with the exact same code: - - a.8 = <blah> - a = a.8 - - The other benefit of performing this optimization relates to what variables - are chosen in copies. Gimplification of the program uses temporaries for - a lot of things. expressions like - - a_1 = <blah> - <blah2> = a_1 - - get turned into - - T.3_5 = <blah> - a_1 = T.3_5 - <blah2> = a_1 - - Copy propagation is done in a forward direction, and if we can propagate - through the copy, we end up with: - - T.3_5 = <blah> - <blah2> = T.3_5 - - The copy is gone, but so is all reference to the user variable 'a'. By - performing this optimization, we would see the sequence: - - a_5 = <blah> - a_1 = a_5 - <blah2> = a_1 - - which copy propagation would then turn into: - - a_5 = <blah> - <blah2> = a_5 - - and so we still retain the user variable whenever possible. */ - - -/* Coalesce the partitions in MAP representing VAR1 and VAR2 if it is valid. - Choose a representative for the partition, and send debug info to DEBUG. */ - -static void -copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug) -{ - int p1, p2, p3; - tree root1, root2; - tree rep1, rep2; - bool ign1, ign2, abnorm; - - gcc_assert (TREE_CODE (var1) == SSA_NAME); - gcc_assert (TREE_CODE (var2) == SSA_NAME); - - register_ssa_partition (map, var1); - register_ssa_partition (map, var2); - - p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1)); - p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2)); - - if (debug) - { - fprintf (debug, "Try : "); - print_generic_expr (debug, var1, TDF_SLIM); - fprintf (debug, "(P%d) & ", p1); - print_generic_expr (debug, var2, TDF_SLIM); - fprintf (debug, "(P%d)", p2); - } - - gcc_assert (p1 != NO_PARTITION); - gcc_assert (p2 != NO_PARTITION); - - if (p1 == p2) - { - if (debug) - fprintf (debug, " : Already coalesced.\n"); - return; - } - - rep1 = partition_to_var (map, p1); - rep2 = partition_to_var (map, p2); - root1 = SSA_NAME_VAR (rep1); - root2 = SSA_NAME_VAR (rep2); - if (!root1 && !root2) - return; - - /* Don't coalesce if one of the variables occurs in an abnormal PHI. */ - abnorm = (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep1) - || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep2)); - if (abnorm) - { - if (debug) - fprintf (debug, " : Abnormal PHI barrier. No coalesce.\n"); - return; - } - - /* Partitions already have the same root, simply merge them. */ - if (root1 == root2) - { - p1 = partition_union (map->var_partition, p1, p2); - if (debug) - fprintf (debug, " : Same root, coalesced --> P%d.\n", p1); - return; - } - - /* Never attempt to coalesce 2 different parameters. */ - if ((root1 && TREE_CODE (root1) == PARM_DECL) - && (root2 && TREE_CODE (root2) == PARM_DECL)) - { - if (debug) - fprintf (debug, " : 2 different PARM_DECLS. No coalesce.\n"); - return; - } - - if ((root1 && TREE_CODE (root1) == RESULT_DECL) - != (root2 && TREE_CODE (root2) == RESULT_DECL)) - { - if (debug) - fprintf (debug, " : One root a RESULT_DECL. No coalesce.\n"); - return; - } - - ign1 = !root1 || (TREE_CODE (root1) == VAR_DECL && DECL_IGNORED_P (root1)); - ign2 = !root2 || (TREE_CODE (root2) == VAR_DECL && DECL_IGNORED_P (root2)); - - /* Refrain from coalescing user variables, if requested. */ - if (!ign1 && !ign2) - { - if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root2)) - ign2 = true; - else if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root1)) - ign1 = true; - else if (flag_ssa_coalesce_vars != 2) - { - if (debug) - fprintf (debug, " : 2 different USER vars. No coalesce.\n"); - return; - } - else - ign2 = true; - } - - /* If both values have default defs, we can't coalesce. If only one has a - tag, make sure that variable is the new root partition. */ - if (root1 && ssa_default_def (cfun, root1)) - { - if (root2 && ssa_default_def (cfun, root2)) - { - if (debug) - fprintf (debug, " : 2 default defs. No coalesce.\n"); - return; - } - else - { - ign2 = true; - ign1 = false; - } - } - else if (root2 && ssa_default_def (cfun, root2)) - { - ign1 = true; - ign2 = false; - } - - /* Do not coalesce if we cannot assign a symbol to the partition. */ - if (!(!ign2 && root2) - && !(!ign1 && root1)) - { - if (debug) - fprintf (debug, " : Choosen variable has no root. No coalesce.\n"); - return; - } - - /* Don't coalesce if the new chosen root variable would be read-only. - If both ign1 && ign2, then the root var of the larger partition - wins, so reject in that case if any of the root vars is TREE_READONLY. - Otherwise reject only if the root var, on which replace_ssa_name_symbol - will be called below, is readonly. */ - if (((root1 && TREE_READONLY (root1)) && ign2) - || ((root2 && TREE_READONLY (root2)) && ign1)) - { - if (debug) - fprintf (debug, " : Readonly variable. No coalesce.\n"); - return; - } - - /* Don't coalesce if the two variables aren't type compatible . */ - if (!types_compatible_p (TREE_TYPE (var1), TREE_TYPE (var2)) - /* There is a disconnect between the middle-end type-system and - VRP, avoid coalescing enum types with different bounds. */ - || ((TREE_CODE (TREE_TYPE (var1)) == ENUMERAL_TYPE - || TREE_CODE (TREE_TYPE (var2)) == ENUMERAL_TYPE) - && TREE_TYPE (var1) != TREE_TYPE (var2))) - { - if (debug) - fprintf (debug, " : Incompatible types. No coalesce.\n"); - return; - } - - /* Merge the two partitions. */ - p3 = partition_union (map->var_partition, p1, p2); - - /* Set the root variable of the partition to the better choice, if there is - one. */ - if (!ign2 && root2) - replace_ssa_name_symbol (partition_to_var (map, p3), root2); - else if (!ign1 && root1) - replace_ssa_name_symbol (partition_to_var (map, p3), root1); - else - gcc_unreachable (); - - if (debug) - { - fprintf (debug, " --> P%d ", p3); - print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)), - TDF_SLIM); - fprintf (debug, "\n"); - } -} - - -namespace { - -const pass_data pass_data_rename_ssa_copies = -{ - GIMPLE_PASS, /* type */ - "copyrename", /* name */ - OPTGROUP_NONE, /* optinfo_flags */ - TV_TREE_COPY_RENAME, /* tv_id */ - ( PROP_cfg | PROP_ssa ), /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - 0, /* todo_flags_finish */ -}; - -class pass_rename_ssa_copies : public gimple_opt_pass -{ -public: - pass_rename_ssa_copies (gcc::context *ctxt) - : gimple_opt_pass (pass_data_rename_ssa_copies, ctxt) - {} - - /* opt_pass methods: */ - opt_pass * clone () { return new pass_rename_ssa_copies (m_ctxt); } - virtual bool gate (function *) { return flag_tree_copyrename != 0; } - virtual unsigned int execute (function *); - -}; // class pass_rename_ssa_copies - -/* This function will make a pass through the IL, and attempt to coalesce any - SSA versions which occur in PHI's or copies. Coalescing is accomplished by - changing the underlying root variable of all coalesced version. This will - then cause the SSA->normal pass to attempt to coalesce them all to the same - variable. */ - -unsigned int -pass_rename_ssa_copies::execute (function *fun) -{ - var_map map; - basic_block bb; - tree var, part_var; - gimple stmt; - unsigned x; - FILE *debug; - - memset (&stats, 0, sizeof (stats)); - - if (dump_file && (dump_flags & TDF_DETAILS)) - debug = dump_file; - else - debug = NULL; - - map = init_var_map (num_ssa_names); - - FOR_EACH_BB_FN (bb, fun) - { - /* Scan for real copies. */ - for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); - gsi_next (&gsi)) - { - stmt = gsi_stmt (gsi); - if (gimple_assign_ssa_name_copy_p (stmt)) - { - tree lhs = gimple_assign_lhs (stmt); - tree rhs = gimple_assign_rhs1 (stmt); - - copy_rename_partition_coalesce (map, lhs, rhs, debug); - } - } - } - - FOR_EACH_BB_FN (bb, fun) - { - /* Treat PHI nodes as copies between the result and each argument. */ - for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); - gsi_next (&gsi)) - { - size_t i; - tree res; - gphi *phi = gsi.phi (); - res = gimple_phi_result (phi); - - /* Do not process virtual SSA_NAMES. */ - if (virtual_operand_p (res)) - continue; - - /* Make sure to only use the same partition for an argument - as the result but never the other way around. */ - if (SSA_NAME_VAR (res) - && !DECL_IGNORED_P (SSA_NAME_VAR (res))) - for (i = 0; i < gimple_phi_num_args (phi); i++) - { - tree arg = PHI_ARG_DEF (phi, i); - if (TREE_CODE (arg) == SSA_NAME) - copy_rename_partition_coalesce (map, res, arg, - debug); - } - /* Else if all arguments are in the same partition try to merge - it with the result. */ - else - { - int all_p_same = -1; - int p = -1; - for (i = 0; i < gimple_phi_num_args (phi); i++) - { - tree arg = PHI_ARG_DEF (phi, i); - if (TREE_CODE (arg) != SSA_NAME) - { - all_p_same = 0; - break; - } - else if (all_p_same == -1) - { - p = partition_find (map->var_partition, - SSA_NAME_VERSION (arg)); - all_p_same = 1; - } - else if (all_p_same == 1 - && p != partition_find (map->var_partition, - SSA_NAME_VERSION (arg))) - { - all_p_same = 0; - break; - } - } - if (all_p_same == 1) - copy_rename_partition_coalesce (map, res, - PHI_ARG_DEF (phi, 0), - debug); - } - } - } - - if (debug) - dump_var_map (debug, map); - - /* Now one more pass to make all elements of a partition share the same - root variable. */ - - for (x = 1; x < num_ssa_names; x++) - { - part_var = partition_to_var (map, x); - if (!part_var) - continue; - var = ssa_name (x); - if (SSA_NAME_VAR (var) == SSA_NAME_VAR (part_var)) - continue; - if (debug) - { - fprintf (debug, "Coalesced "); - print_generic_expr (debug, var, TDF_SLIM); - fprintf (debug, " to "); - print_generic_expr (debug, part_var, TDF_SLIM); - fprintf (debug, "\n"); - } - stats.coalesced++; - replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var)); - } - - statistics_counter_event (fun, "copies coalesced", - stats.coalesced); - delete_var_map (map); - return 0; -} - -} // anon namespace - -gimple_opt_pass * -make_pass_rename_ssa_copies (gcc::context *ctxt) -{ - return new pass_rename_ssa_copies (ctxt); -} |