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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/52005] New: tree-ssa-combineif does not work with some cfgs
Date: Thu, 26 Jan 2012 08:03:00 -0000 [thread overview]
Message-ID: <bug-52005-4@http.gcc.gnu.org/bugzilla/> (raw)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52005
Bug #: 52005
Summary: tree-ssa-combineif does not work with some cfgs
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: pinskia@gcc.gnu.org
Take:
int f(int x, int a, int b)
{
int t = 0;
int c = 1 << a;
if (!(x & 1))
t = 0;
else
if (x & (1 << 2))
t = 1;
else
t = 0;
return t;
}
int f1(int x, int a, int b)
{
int t = 0;
int c = 1 << a;
if (x & 1)
if (x & (1 << 2))
t = 1;
return t;
}
--- CUT ---
Both codes are the same. The first case is not optimized while the second is.
The reason is we have code in ifcombine which only looks for the second case.
While the first is not caught.
next reply other threads:[~2012-01-26 3:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-26 8:03 pinskia at gcc dot gnu.org [this message]
2012-01-26 8:21 ` [Bug tree-optimization/52005] " pinskia at gcc dot gnu.org
2012-01-26 23:20 ` pinskia at gcc dot gnu.org
2012-08-06 16:39 ` glisse at gcc dot gnu.org
2012-08-06 16:58 ` glisse at gcc dot gnu.org
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