From 5d1c1f55d54adb95d9fa3bdfa28170d87c830d9c Mon Sep 17 00:00:00 2001
From: ebotcazou <ebotcazou@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Wed, 13 Nov 2013 12:15:47 +0000
Subject: * cfgexpand.c (expand_used_vars): Allocate space for
partitions based on PARM_DECLs or RESULT_DECLs only if they are ignored
for debug info or if optimization is enabled. * tree-ssa-coalesce.c
(coalesce_ssa_name): If optimization is disabled, require that all the
names based on a PARM_DECL or a RESULT_DECL that isn't ignored for
debug info be coalesced.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@204742 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/tree-ssa-coalesce.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
(limited to 'gcc/tree-ssa-coalesce.c')
diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c
index c445c78626e..252fc33a7f0 100644
--- a/gcc/tree-ssa-coalesce.c
+++ b/gcc/tree-ssa-coalesce.c
@@ -1256,8 +1256,8 @@ coalesce_ssa_name (void)
cl = create_coalesce_list ();
map = create_outofssa_var_map (cl, used_in_copies);
- /* We need to coalesce all names originating same SSA_NAME_VAR
- so debug info remains undisturbed. */
+ /* If optimization is disabled, we need to coalesce all the names originating
+ from the same SSA_NAME_VAR so debug info remains undisturbed. */
if (!optimize)
{
hash_table <ssa_name_var_hash> ssa_name_hash;
@@ -1278,8 +1278,16 @@ coalesce_ssa_name (void)
*slot = a;
else
{
- add_coalesce (cl, SSA_NAME_VERSION (a), SSA_NAME_VERSION (*slot),
- MUST_COALESCE_COST - 1);
+ /* If the variable is a PARM_DECL or a RESULT_DECL, we
+ _require_ that all the names originating from it be
+ coalesced, because there must be a single partition
+ containing all the names so that it can be assigned
+ the canonical RTL location of the DECL safely. */
+ const int cost
+ = TREE_CODE (SSA_NAME_VAR (a)) == VAR_DECL
+ ? MUST_COALESCE_COST - 1 : MUST_COALESCE_COST;
+ add_coalesce (cl, SSA_NAME_VERSION (a),
+ SSA_NAME_VERSION (*slot), cost);
bitmap_set_bit (used_in_copies, SSA_NAME_VERSION (a));
bitmap_set_bit (used_in_copies, SSA_NAME_VERSION (*slot));
}
--
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