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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/48590] New: Alias analysis confused by builtin-stack-save/restore
Date: Wed, 13 Apr 2011 11:02:00 -0000 [thread overview]
Message-ID: <bug-48590-4@http.gcc.gnu.org/bugzilla/> (raw)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48590
Summary: Alias analysis confused by builtin-stack-save/restore
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: middle-end
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: rguenth@gcc.gnu.org
Lame testcase for now:
float foo (int i, double *d)
{
float f;
double dd;
int j;
dd = *d;
for (j = 0; j<i; ++j)
{
float a[i];
f+=a[j] + *d + dd;
}
return f;
}
we fail to CSE *d because we think that __builtin_stack_save () clobbers it.
__builtin_stack_restore () has similar effects on DSE (it appears to use
all aliased memory).
We have to be careful when improving this to not allow sinking operations
on alloca'd memory over a __builtin_stack_restore ().
next reply other threads:[~2011-04-13 11:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-13 11:02 rguenth at gcc dot gnu.org [this message]
2011-04-13 11:04 ` [Bug middle-end/48590] " rguenth at gcc dot gnu.org
2011-04-13 11:13 ` rguenth at gcc dot gnu.org
2011-04-14 12:19 ` rguenth at gcc dot gnu.org
2011-04-14 12:37 ` rguenth at gcc dot gnu.org
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