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* [Bug middle-end/35346] New: Scalar replacement -- handling of conditional generator -- missing
@ 2008-02-24 4:47 xinliangli at gmail dot com
2008-02-24 21:52 ` [Bug middle-end/35346] " rguenth at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: xinliangli at gmail dot com @ 2008-02-24 4:47 UTC (permalink / raw)
To: gcc-bugs
// David Li:
Conditional generator is not handled, missing redundancy elimination for a[i]
and a[i-1]
int a[1000];
int b[1000];
void foo(int n)
{
int i = 1;
for(; i < n; i++)
{
if (b[i] > 0)
a[i+1] = a[i-1];
b[i] = a[i];
}
}
==> should be (similar to PRE)
Conditional generator is not handled, missing redundancy elimination for a[i]
and a[i-1]
int a[1000];
int b[1000];
t1 = a[0];
t2 = a[1];
void foo(int n)
{
int i = 1;
for(; i < n; i++)
{
if (b[i] > 0)
{
t3 = t1;
a[i+1] = t3;
}
else t3 = a[i+1];
b[i] = t2;
t1 = t2;
t2 = t3;
}
}
(Loop can be unrolled to reduce copy)
--
Summary: Scalar replacement -- handling of conditional generator
-- missing
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: xinliangli at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35346
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/35346] Scalar replacement -- handling of conditional generator -- missing
2008-02-24 4:47 [Bug middle-end/35346] New: Scalar replacement -- handling of conditional generator -- missing xinliangli at gmail dot com
@ 2008-02-24 21:52 ` rguenth at gcc dot gnu dot org
2008-04-07 1:38 ` pinskia at gcc dot gnu dot org
2008-12-29 6:18 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2008-02-24 21:52 UTC (permalink / raw)
To: gcc-bugs
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Keywords| |missed-optimization
Version|unknown |4.3.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35346
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/35346] Scalar replacement -- handling of conditional generator -- missing
2008-02-24 4:47 [Bug middle-end/35346] New: Scalar replacement -- handling of conditional generator -- missing xinliangli at gmail dot com
2008-02-24 21:52 ` [Bug middle-end/35346] " rguenth at gcc dot gnu dot org
@ 2008-04-07 1:38 ` pinskia at gcc dot gnu dot org
2008-12-29 6:18 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2008-04-07 1:38 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2008-04-07 01:37 -------
Confirmed.
--
pinskia 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 |2008-04-07 01:37:59
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35346
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/35346] Scalar replacement -- handling of conditional generator -- missing
2008-02-24 4:47 [Bug middle-end/35346] New: Scalar replacement -- handling of conditional generator -- missing xinliangli at gmail dot com
2008-02-24 21:52 ` [Bug middle-end/35346] " rguenth at gcc dot gnu dot org
2008-04-07 1:38 ` pinskia at gcc dot gnu dot org
@ 2008-12-29 6:18 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2008-12-29 6:18 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from pinskia at gcc dot gnu dot org 2008-12-29 06:15 -------
Hmm:
MEM[symbol: b, index: ivtmp.27, step: 4, offset: 4294967292]
Why do we produce a step and an offset when they cancel?
If we change the store to a[i+1] to be unconditional, predictive commoning does
the correct thing.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2008-04-07 01:37:59 |2008-12-29 06:15:08
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35346
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2008-12-29 6:18 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2008-02-24 4:47 [Bug middle-end/35346] New: Scalar replacement -- handling of conditional generator -- missing xinliangli at gmail dot com
2008-02-24 21:52 ` [Bug middle-end/35346] " rguenth at gcc dot gnu dot org
2008-04-07 1:38 ` pinskia at gcc dot gnu dot org
2008-12-29 6:18 ` pinskia at gcc dot gnu dot org
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