From: Jan Hubicka <hubicka@kam.mff.cuni.cz>
To: gcc-patches@gcc.gnu.org
Subject: Fix wrong code in ldist-strlen-1.c
Date: Sat, 16 Oct 2021 14:47:51 +0200 [thread overview]
Message-ID: <20211016124751.GB52572@kam.mff.cuni.cz> (raw)
Hi,
while updating compute_points_to_sets I missed that the code not only
sets the nonlocal/escaped flags but also initializes pt. With my
previous change if uses_global_memory is false pt is not updated
correctly which may lead to wrong code.
This is fixed by the following patch I comitted to avoid strange
misoptimizations.
Bootstrapped/regtested x86_64-linux and also tested with LTO.
Honza
gcc/ChangeLog:
PR tree-optimization/102720
* tree-ssa-structalias.c (compute_points_to_sets): Fix producing
of call used and clobbered sets.
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 6f12a66ee0d..2e6513bb72a 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -7541,17 +7541,18 @@ compute_points_to_sets (void)
determine_global_memory_access (stmt, NULL,
&reads_global_memory,
&uses_global_memory);
- if (!uses_global_memory)
- ;
- else if ((vi = lookup_call_use_vi (stmt)) != NULL)
+ if ((vi = lookup_call_use_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly used by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
- pt->nonlocal = uses_global_memory;
- pt->escaped = uses_global_memory;
+ if (uses_global_memory)
+ {
+ pt->nonlocal = uses_global_memory;
+ pt->escaped = uses_global_memory;
+ }
}
else if (uses_global_memory)
{
@@ -7572,17 +7573,18 @@ compute_points_to_sets (void)
determine_global_memory_access (stmt, &writes_global_memory,
NULL, NULL);
- if (!writes_global_memory)
- ;
- else if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
+ if ((vi = lookup_call_clobber_vi (stmt)) != NULL)
{
*pt = find_what_var_points_to (cfun->decl, vi);
/* Escaped (and thus nonlocal) variables are always
implicitly clobbered by calls. */
/* ??? ESCAPED can be empty even though NONLOCAL
always escaped. */
- pt->nonlocal = writes_global_memory;
- pt->escaped = writes_global_memory;
+ if (writes_global_memory)
+ {
+ pt->nonlocal = writes_global_memory;
+ pt->escaped = writes_global_memory;
+ }
}
else if (writes_global_memory)
{
next reply other threads:[~2021-10-16 12:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-16 12:47 Jan Hubicka [this message]
2021-10-16 15:46 ` Richard Biener
2021-10-16 15:58 ` H.J. Lu
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