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* [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk)
@ 2013-08-29 23:30 su at cs dot ucdavis.edu
2013-08-29 23:31 ` [Bug tree-optimization/58277] " su at cs dot ucdavis.edu
` (12 more replies)
0 siblings, 13 replies; 14+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-08-29 23:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Bug ID: 58277
Summary: wrong code at -O3 (affecting 4.7, 4.8, and trunk)
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
The current gcc trunk (as well as gcc 4.7 and 4.8) produces wrong code for the
attached testcase on x86_64-linux when compiled at -O3 in 32-bit mode. It is a
regression from 4.6.x.
This one has been quite nasty to reduce; the attached testcase is the simplest
I was able to get. I believe it doesn't have any undefined behavior.
$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.9.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure
--enable-languages=c,c++,objc,obj-c++,fortran,lto
--with-gmp=/usr/local/gcc-trunk --with-mpfr=/usr/local/gcc-trunk
--with-mpc=/usr/local/gcc-trunk --with-cloog=/usr/local/gcc-trunk
--prefix=/usr/local/gcc-trunk
Thread model: posix
gcc version 4.9.0 20130829 (experimental) [trunk revision 202067] (GCC)
$ gcc-trunk -m32 -O2 small.c
$ a.out
0
$ gcc-4.6 -m32 -O3 small.c
$ a.out
0
$ gcc-trunk -m32 -O3 small.c
$ a.out
0
Aborted (core dumped)
$ gcc-4.7 -m32 -O3 small.c
$ a.out
0
Aborted (core dumped)
$ gcc-4.8 -m32 -O3 small.c
$ a.out
0
Aborted (core dumped)
$
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] wrong code at -O3 (affecting 4.7, 4.8, and trunk)
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
@ 2013-08-29 23:31 ` su at cs dot ucdavis.edu
2013-08-29 23:39 ` su at cs dot ucdavis.edu
` (11 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-08-29 23:31 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #1 from Zhendong Su <su at cs dot ucdavis.edu> ---
Created attachment 30725
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30725&action=edit
testcase
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] wrong code at -O3 (affecting 4.7, 4.8, and trunk)
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
2013-08-29 23:31 ` [Bug tree-optimization/58277] " su at cs dot ucdavis.edu
@ 2013-08-29 23:39 ` su at cs dot ucdavis.edu
2013-08-29 23:40 ` su at cs dot ucdavis.edu
` (10 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-08-29 23:39 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #2 from Zhendong Su <su at cs dot ucdavis.edu> ---
I'm also attaching a related testcase (small2.c) for both 32-bit and 64-bit
modes.
$ gcc-trunk -m64 -O2 small2.c
$ a.out
$ gcc-4.6 -m64 -O3 small2.c
$ a.out
$ gcc-4.7 -m64 -O3 small2.c
$ a.out
Aborted (core dumped)
$ gcc-4.8 -m64 -O3 small2.c
$ a.out
Aborted (core dumped)
$ gcc-trunk -m64 -O3 small2.c
$ a.out
Aborted (core dumped)
$
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] wrong code at -O3 (affecting 4.7, 4.8, and trunk)
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
2013-08-29 23:31 ` [Bug tree-optimization/58277] " su at cs dot ucdavis.edu
2013-08-29 23:39 ` su at cs dot ucdavis.edu
@ 2013-08-29 23:40 ` su at cs dot ucdavis.edu
2013-08-30 7:39 ` [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3 jakub at gcc dot gnu.org
` (9 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-08-29 23:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #3 from Zhendong Su <su at cs dot ucdavis.edu> ---
Created attachment 30726
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30726&action=edit
another testcase for both 32-bit and 64-bit modes
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (2 preceding siblings ...)
2013-08-29 23:40 ` su at cs dot ucdavis.edu
@ 2013-08-30 7:39 ` jakub at gcc dot gnu.org
2013-08-30 8:00 ` mpolacek at gcc dot gnu.org
` (8 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 7:39 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
Target Milestone|--- |4.7.4
Summary|wrong code at -O3 |[4.7/4.8/4.9 Regression]
|(affecting 4.7, 4.8, and |wrong code at -O3
|trunk) |
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Both testcases started to fail with r181172.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (3 preceding siblings ...)
2013-08-30 7:39 ` [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3 jakub at gcc dot gnu.org
@ 2013-08-30 8:00 ` mpolacek at gcc dot gnu.org
2013-08-30 8:02 ` jakub at gcc dot gnu.org
` (7 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2013-08-30 8:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2013-08-30
CC| |matz at gcc dot gnu.org,
| |mpolacek at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Thus confirmed.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (4 preceding siblings ...)
2013-08-30 8:00 ` mpolacek at gcc dot gnu.org
@ 2013-08-30 8:02 ` jakub at gcc dot gnu.org
2013-08-30 9:31 ` jakub at gcc dot gnu.org
` (6 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 8:02 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
But, skimming through the dumps, it looks like it is the strlen pass that
removes the important n = 0; store.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (5 preceding siblings ...)
2013-08-30 8:02 ` jakub at gcc dot gnu.org
@ 2013-08-30 9:31 ` jakub at gcc dot gnu.org
2013-08-30 12:41 ` jakub at gcc dot gnu.org
` (5 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 9:31 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |jakub at gcc dot gnu.org
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 30728
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30728&action=edit
gcc49-pr58277.patch
Untested fix.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (6 preceding siblings ...)
2013-08-30 9:31 ` jakub at gcc dot gnu.org
@ 2013-08-30 12:41 ` jakub at gcc dot gnu.org
2013-08-30 12:53 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 12:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Aug 30 12:41:17 2013
New Revision: 202104
URL: http://gcc.gnu.org/viewcvs?rev=202104&root=gcc&view=rev
Log:
PR tree-optimization/58277
* tree-ssa-strlen.c (strlen_enter_block): If do_invalidate gave up
after seeing too many stmts with vdef in between dombb and current
bb, invalidate everything.
* gcc.c-torture/execute/pr58277-1.c: New test.
* gcc.c-torture/execute/pr58277-2.c: New test.
Added:
trunk/gcc/testsuite/gcc.c-torture/execute/pr58277-1.c
trunk/gcc/testsuite/gcc.c-torture/execute/pr58277-2.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-ssa-strlen.c
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7/4.8/4.9 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (7 preceding siblings ...)
2013-08-30 12:41 ` jakub at gcc dot gnu.org
@ 2013-08-30 12:53 ` jakub at gcc dot gnu.org
2013-08-30 12:58 ` [Bug tree-optimization/58277] [4.7 " jakub at gcc dot gnu.org
` (3 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 12:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Fri Aug 30 12:53:47 2013
New Revision: 202105
URL: http://gcc.gnu.org/viewcvs?rev=202105&root=gcc&view=rev
Log:
PR tree-optimization/58277
* tree-ssa-strlen.c (strlen_enter_block): If do_invalidate gave up
after seeing too many stmts with vdef in between dombb and current
bb, invalidate everything.
* gcc.c-torture/execute/pr58277-1.c: New test.
* gcc.c-torture/execute/pr58277-2.c: New test.
Added:
branches/gcc-4_8-branch/gcc/testsuite/gcc.c-torture/execute/pr58277-1.c
branches/gcc-4_8-branch/gcc/testsuite/gcc.c-torture/execute/pr58277-2.c
Modified:
branches/gcc-4_8-branch/gcc/ChangeLog
branches/gcc-4_8-branch/gcc/testsuite/ChangeLog
branches/gcc-4_8-branch/gcc/tree-ssa-strlen.c
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (8 preceding siblings ...)
2013-08-30 12:53 ` jakub at gcc dot gnu.org
@ 2013-08-30 12:58 ` jakub at gcc dot gnu.org
2013-08-30 16:46 ` su at cs dot ucdavis.edu
` (2 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-08-30 12:58 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.7/4.8/4.9 Regression] |[4.7 Regression] wrong code
|wrong code at -O3 |at -O3
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 4.8+ so far, thanks for reporting it.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (9 preceding siblings ...)
2013-08-30 12:58 ` [Bug tree-optimization/58277] [4.7 " jakub at gcc dot gnu.org
@ 2013-08-30 16:46 ` su at cs dot ucdavis.edu
2014-05-07 16:02 ` jakub at gcc dot gnu.org
2014-05-07 16:19 ` jakub at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-08-30 16:46 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #11 from Zhendong Su <su at cs dot ucdavis.edu> ---
(In reply to Jakub Jelinek from comment #10)
> Fixed for 4.8+ so far, thanks for reporting it.
Thanks Jakub. Wow, that's quick! You folks are wonderful.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (10 preceding siblings ...)
2013-08-30 16:46 ` su at cs dot ucdavis.edu
@ 2014-05-07 16:02 ` jakub at gcc dot gnu.org
2014-05-07 16:19 ` jakub at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-05-07 16:02 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Wed May 7 16:01:24 2014
New Revision: 210171
URL: http://gcc.gnu.org/viewcvs?rev=210171&root=gcc&view=rev
Log:
Backported from mainline
2013-08-30 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/58277
* tree-ssa-strlen.c (strlen_enter_block): If do_invalidate gave up
after seeing too many stmts with vdef in between dombb and current
bb, invalidate everything.
* gcc.c-torture/execute/pr58277-1.c: New test.
* gcc.c-torture/execute/pr58277-2.c: New test.
Added:
branches/gcc-4_7-branch/gcc/testsuite/gcc.c-torture/execute/pr58277-1.c
branches/gcc-4_7-branch/gcc/testsuite/gcc.c-torture/execute/pr58277-2.c
Modified:
branches/gcc-4_7-branch/gcc/ChangeLog
branches/gcc-4_7-branch/gcc/testsuite/ChangeLog
branches/gcc-4_7-branch/gcc/tree-ssa-strlen.c
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug tree-optimization/58277] [4.7 Regression] wrong code at -O3
2013-08-29 23:30 [Bug tree-optimization/58277] New: wrong code at -O3 (affecting 4.7, 4.8, and trunk) su at cs dot ucdavis.edu
` (11 preceding siblings ...)
2014-05-07 16:02 ` jakub at gcc dot gnu.org
@ 2014-05-07 16:19 ` jakub at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-05-07 16:19 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58277
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 14+ messages in thread
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