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* [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable
@ 2020-08-19 13:26 gabravier at gmail dot com
2020-08-19 13:30 ` [Bug tree-optimization/96708] " gabravier at gmail dot com
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: gabravier at gmail dot com @ 2020-08-19 13:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
Bug ID: 96708
Summary: Failure to optimize max pattern with comparison when
using a temporary variable
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
bool f(int a, int b)
{
int tmp = (a < b) ? b : a;
return tmp >= a;
}
This can be optimized to `return true;`. This transformation is done by LLVM,
but not by GCC.
PS: This is probably related to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95926.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
@ 2020-08-19 13:30 ` gabravier at gmail dot com
2020-08-24 20:12 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: gabravier at gmail dot com @ 2020-08-19 13:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
--- Comment #1 from Gabriel Ravier <gabravier at gmail dot com> ---
PS: This especially affects, for example, C++ code that uses std::max, which
fails to optimize properly compared to, for example, a `max` macro.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
2020-08-19 13:30 ` [Bug tree-optimization/96708] " gabravier at gmail dot com
@ 2020-08-24 20:12 ` pinskia at gcc dot gnu.org
2020-08-25 11:09 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2020-08-24 20:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
2020-08-19 13:30 ` [Bug tree-optimization/96708] " gabravier at gmail dot com
2020-08-24 20:12 ` pinskia at gcc dot gnu.org
@ 2020-08-25 11:09 ` rguenth at gcc dot gnu.org
2020-12-01 23:29 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-08-25 11:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |easyhack
Last reconfirmed| |2020-08-25
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.
_4 = MAX_EXPR <a_2(D), b_3(D)>;
_7 = a_2(D) <= _4;
return _7;
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
` (2 preceding siblings ...)
2020-08-25 11:09 ` rguenth at gcc dot gnu.org
@ 2020-12-01 23:29 ` cvs-commit at gcc dot gnu.org
2020-12-01 23:29 ` law at redhat dot com
2023-09-11 2:21 ` pinskia at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-12-01 23:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jeff Law <law@gcc.gnu.org>:
https://gcc.gnu.org/g:abef36919f741c8e4f7380b2c2ffbc6ad97c2b6b
commit r11-5631-gabef36919f741c8e4f7380b2c2ffbc6ad97c2b6b
Author: Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>
Date: Tue Dec 1 16:26:59 2020 -0700
Optimize max/min pattern with comparison
gcc/
PR tree-optimization/96708
* match.pd: New pattern for comparing X with MAX (X, Y)
or MIN (X, y).
gcc/testsuite
* gcc.dg/pr96708-negative.c: New test.
* gcc.dg/pr96708-positive.c: New test.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
` (3 preceding siblings ...)
2020-12-01 23:29 ` cvs-commit at gcc dot gnu.org
@ 2020-12-01 23:29 ` law at redhat dot com
2023-09-11 2:21 ` pinskia at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: law at redhat dot com @ 2020-12-01 23:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |law at redhat dot com
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
Should be fixed with Eugene's patch on the trunk
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug tree-optimization/96708] Failure to optimize max pattern with comparison when using a temporary variable
2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
` (4 preceding siblings ...)
2020-12-01 23:29 ` law at redhat dot com
@ 2023-09-11 2:21 ` pinskia at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-11 2:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96708
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |11.0
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this was mostly fixed for GCC 11 but had missed the :c on the cmp and that
was fully fixed in GCC 14, see PR 111346 for that. What that means is sometimes
we would not optimize always to 0/1 and keep around the comparison.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-09-11 2:21 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2020-08-19 13:26 [Bug tree-optimization/96708] New: Failure to optimize max pattern with comparison when using a temporary variable gabravier at gmail dot com
2020-08-19 13:30 ` [Bug tree-optimization/96708] " gabravier at gmail dot com
2020-08-24 20:12 ` pinskia at gcc dot gnu.org
2020-08-25 11:09 ` rguenth at gcc dot gnu.org
2020-12-01 23:29 ` cvs-commit at gcc dot gnu.org
2020-12-01 23:29 ` law at redhat dot com
2023-09-11 2:21 ` pinskia at gcc dot gnu.org
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