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* [Bug tree-optimization/37541] New: VRP fails to optimize single-bit ranges
@ 2008-09-16 12:37 rguenth at gcc dot gnu dot org
2010-07-28 14:43 ` [Bug tree-optimization/37541] " rguenth at gcc dot gnu dot org
0 siblings, 1 reply; 3+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-09-16 12:37 UTC (permalink / raw)
To: gcc-bugs
gcc.dg/tree-ssa/pr37508.c is XFAILed because of this.
struct foo1 {
int i:1;
};
int test1 (struct foo1 *x)
{
if (x->i == 0)
return 1;
else if (x->i == -1)
return 1;
return 0;
}
VRP should figure out that the function always returns 1.
--
Summary: VRP fails to optimize single-bit ranges
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Keywords: missed-optimization, xfail
Severity: enhancement
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37541
^ permalink raw reply [flat|nested] 3+ messages in thread* [Bug tree-optimization/37541] VRP fails to optimize single-bit ranges
2008-09-16 12:37 [Bug tree-optimization/37541] New: " rguenth at gcc dot gnu dot org
@ 2010-07-28 14:43 ` rguenth at gcc dot gnu dot org
0 siblings, 0 replies; 3+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2010-07-28 14:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2010-07-28 14:43 -------
This seems fixed, just the optimizations in question are already performed
partly by FRE but one,
test2 (struct foo2 * x)
{
...
<bb 2>:
D.2745_3 = BIT_FIELD_REF <*x_2(D), 8, 0>;
D.2746_4 = D.2745_3 & 1;
if (D.2746_4 == 0)
goto <bb 5>;
else
goto <bb 3>;
<bb 3>:
D.2750_6 = x_2(D)->i;
where for some reason our strange aggregate-bit-field-ref folding triggers
only for one load.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-07-28 14:43:02
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37541
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-06-29 13:58 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2012-06-29 13:57 ` [Bug tree-optimization/37541] VRP fails to optimize single-bit ranges rguenth at gcc dot gnu.org
2012-06-29 13:58 ` rguenth at gcc dot gnu.org
2008-09-16 12:37 [Bug tree-optimization/37541] New: " rguenth at gcc dot gnu dot org
2010-07-28 14:43 ` [Bug tree-optimization/37541] " rguenth at gcc dot gnu dot org
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