public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c/27781] New: weak-attribute over-optimisation with 4.1
@ 2006-05-28 9:39 jan dot kiszka at web dot de
2006-05-28 12:04 ` [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation rguenth at gcc dot gnu dot org
` (10 more replies)
0 siblings, 11 replies; 12+ messages in thread
From: jan dot kiszka at web dot de @ 2006-05-28 9:39 UTC (permalink / raw)
To: gcc-bugs
file-a.c:
---------
void __attribute__((weak)) func(void)
{
/* no code */
}
main()
{
func();
}
file-b.c:
---------
void func(void)
{
printf("func\n");
}
# gcc -c file-a.c file-b.c -O2
# gcc -o program file-a.o file-b.o
The program will not print "func", because the call to func() was optimised out
during the compilation of file-a.c. This happens with -O2, but not when using
-fno-unit-at-a-time. First sighted in 4.1.
--
Summary: weak-attribute over-optimisation with 4.1
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jan dot kiszka at web dot de
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
@ 2006-05-28 12:04 ` rguenth at gcc dot gnu dot org
2006-05-28 14:00 ` rguenth at gcc dot gnu dot org
` (9 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-05-28 12:04 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2006-05-28 12:03 -------
ipa-pure-const thinks that func is const, which is wrong. Then DCE comes along
and deletes the function call.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Keywords| |wrong-code
Last reconfirmed|0000-00-00 00:00:00 |2006-05-28 12:03:59
date| |
Summary|weak-attribute over- |[4.1/4.2 Regression] weak-
|optimisation with 4.1 |attribute over-optimisation
Target Milestone|--- |4.1.2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
2006-05-28 12:04 ` [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation rguenth at gcc dot gnu dot org
@ 2006-05-28 14:00 ` rguenth at gcc dot gnu dot org
2006-05-28 15:23 ` [Bug middle-end/27781] " pinskia at gcc dot gnu dot org
` (8 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-05-28 14:00 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rguenth at gcc dot gnu dot org 2006-05-28 14:00 -------
I have a patch.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
Last reconfirmed|2006-05-28 12:03:59 |2006-05-28 14:00:23
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
2006-05-28 12:04 ` [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation rguenth at gcc dot gnu dot org
2006-05-28 14:00 ` rguenth at gcc dot gnu dot org
@ 2006-05-28 15:23 ` pinskia at gcc dot gnu dot org
2006-06-01 18:36 ` trini at kernel dot crashing dot org
` (7 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-05-28 15:23 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from pinskia at gcc dot gnu dot org 2006-05-28 15:23 -------
Actually no, you have to use -fPIC to get this not to be optimized, otherwise
func will be bound locally which is not what you want.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |middle-end
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (2 preceding siblings ...)
2006-05-28 15:23 ` [Bug middle-end/27781] " pinskia at gcc dot gnu dot org
@ 2006-06-01 18:36 ` trini at kernel dot crashing dot org
2006-06-04 19:32 ` mmitchel at gcc dot gnu dot org
` (6 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: trini at kernel dot crashing dot org @ 2006-06-01 18:36 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from trini at kernel dot crashing dot org 2006-06-01 18:36 -------
(In reply to comment #3)
> Actually no, you have to use -fPIC to get this not to be optimized, otherwise
> func will be bound locally which is not what you want.
Two things. First, that's a change in behavior from how it used to work and I
don't recall seeing warnings about going-away behavior (the place this problem
is actually manifesting is in code for the Linux Kernel).
Second there is some sort of bug here as if we have:
$ cat file-a.c
void __attribute__((weak)) func(void)
{
printf("weak\n");
}
main()
{
func();
}
$ cat file-b.c
void func(void)
{
printf("func\n");
}
$ gcc-4.1 -c file-a.c file-b.c -O2
file-a.c: In function 'func':
file-a.c:3: warning: incompatible implicit declaration of built-in function
'printf'
file-b.c: In function 'func':
file-b.c:3: warning: incompatible implicit declaration of built-in function
'printf'
$ gcc-4.1 -o program file-a.o file-b.o
$ ./program
func
$ gcc-4.1 -o program file-a.o
$ ./program
weak
$ gcc-4.1 -v
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,java,fortran,objc,obj-c++,ada,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--program-suffix=-4.1 --enable-__cxa_atexit --enable-clocale=gnu
--enable-libstdcxx-debug --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.1-1.4.2.0/jre --enable-mpfr
--enable-checking=release x86_64-linux-gnu
Thread model: posix
gcc version 4.1.0 (Debian 4.1.0-1)
--
trini at kernel dot crashing dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |trini at kernel dot crashing
| |dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (3 preceding siblings ...)
2006-06-01 18:36 ` trini at kernel dot crashing dot org
@ 2006-06-04 19:32 ` mmitchel at gcc dot gnu dot org
2006-06-15 15:54 ` patchapp at dberlin dot org
` (5 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: mmitchel at gcc dot gnu dot org @ 2006-06-04 19:32 UTC (permalink / raw)
To: gcc-bugs
--
mmitchel at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P2
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (4 preceding siblings ...)
2006-06-04 19:32 ` mmitchel at gcc dot gnu dot org
@ 2006-06-15 15:54 ` patchapp at dberlin dot org
2006-06-15 17:30 ` rguenth at gcc dot gnu dot org
` (4 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: patchapp at dberlin dot org @ 2006-06-15 15:54 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from patchapp at dberlin dot org 2006-06-15 15:30 -------
Subject: Bug number PR27781
A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-06/msg00808.html
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1/4.2 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (5 preceding siblings ...)
2006-06-15 15:54 ` patchapp at dberlin dot org
@ 2006-06-15 17:30 ` rguenth at gcc dot gnu dot org
2006-06-15 17:39 ` [Bug middle-end/27781] [4.1 " rguenth at gcc dot gnu dot org
` (3 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-06-15 17:30 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from rguenth at gcc dot gnu dot org 2006-06-15 17:23 -------
Subject: Bug 27781
Author: rguenth
Date: Thu Jun 15 17:23:41 2006
New Revision: 114681
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=114681
Log:
2006-06-16 Richard Guenther <rguenther@suse.de>
PR tree-optimization/27781
* Makefile.in (ipa-pure-const.o): Add $(TARGET_H) dependency.
* ipa-pure-const.c (target.h): Include.
(analyze_function): Do not analyze functions that do not
bind locally.
* gcc.dg/tree-ssa/pr27781.c: New testcase.
Added:
trunk/gcc/testsuite/gcc.dg/tree-ssa/pr27781.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/Makefile.in
trunk/gcc/ipa-pure-const.c
trunk/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (6 preceding siblings ...)
2006-06-15 17:30 ` rguenth at gcc dot gnu dot org
@ 2006-06-15 17:39 ` rguenth at gcc dot gnu dot org
2006-06-16 17:53 ` pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-06-15 17:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from rguenth at gcc dot gnu dot org 2006-06-15 17:30 -------
Fixed on the mainline.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.1/4.2 Regression] weak- |[4.1 Regression] weak-
|attribute over-optimisation |attribute over-optimisation
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (7 preceding siblings ...)
2006-06-15 17:39 ` [Bug middle-end/27781] [4.1 " rguenth at gcc dot gnu dot org
@ 2006-06-16 17:53 ` pinskia at gcc dot gnu dot org
2006-06-21 15:36 ` rguenth at gcc dot gnu dot org
2006-06-21 15:43 ` rguenth at gcc dot gnu dot org
10 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-06-16 17:53 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from pinskia at gcc dot gnu dot org 2006-06-16 17:50 -------
*** Bug 28055 has been marked as a duplicate of this bug. ***
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |saito at densan dot co dot
| |jp
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (8 preceding siblings ...)
2006-06-16 17:53 ` pinskia at gcc dot gnu dot org
@ 2006-06-21 15:36 ` rguenth at gcc dot gnu dot org
2006-06-21 15:43 ` rguenth at gcc dot gnu dot org
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-06-21 15:36 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from rguenth at gcc dot gnu dot org 2006-06-21 15:36 -------
Fixed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug middle-end/27781] [4.1 Regression] weak-attribute over-optimisation
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
` (9 preceding siblings ...)
2006-06-21 15:36 ` rguenth at gcc dot gnu dot org
@ 2006-06-21 15:43 ` rguenth at gcc dot gnu dot org
10 siblings, 0 replies; 12+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-06-21 15:43 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from rguenth at gcc dot gnu dot org 2006-06-21 15:36 -------
Subject: Bug 27781
Author: rguenth
Date: Wed Jun 21 15:36:10 2006
New Revision: 114852
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=114852
Log:
2006-06-21 Richard Guenther <rguenther@suse.de>
PR tree-optimization/27781
* Makefile.in (ipa-pure-const.o): Add $(TARGET_H) dependency.
* ipa-pure-const.c (target.h): Include.
(analyze_function): Do not analyze functions that do not
bind locally.
* gcc.dg/tree-ssa/pr27781.c: New testcase.
Added:
branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/tree-ssa/pr27781.c
- copied unchanged from r114681,
trunk/gcc/testsuite/gcc.dg/tree-ssa/pr27781.c
Modified:
branches/gcc-4_1-branch/gcc/ChangeLog
branches/gcc-4_1-branch/gcc/Makefile.in
branches/gcc-4_1-branch/gcc/ipa-pure-const.c
branches/gcc-4_1-branch/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27781
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2006-06-21 15:36 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-05-28 9:39 [Bug c/27781] New: weak-attribute over-optimisation with 4.1 jan dot kiszka at web dot de
2006-05-28 12:04 ` [Bug c/27781] [4.1/4.2 Regression] weak-attribute over-optimisation rguenth at gcc dot gnu dot org
2006-05-28 14:00 ` rguenth at gcc dot gnu dot org
2006-05-28 15:23 ` [Bug middle-end/27781] " pinskia at gcc dot gnu dot org
2006-06-01 18:36 ` trini at kernel dot crashing dot org
2006-06-04 19:32 ` mmitchel at gcc dot gnu dot org
2006-06-15 15:54 ` patchapp at dberlin dot org
2006-06-15 17:30 ` rguenth at gcc dot gnu dot org
2006-06-15 17:39 ` [Bug middle-end/27781] [4.1 " rguenth at gcc dot gnu dot org
2006-06-16 17:53 ` pinskia at gcc dot gnu dot org
2006-06-21 15:36 ` rguenth at gcc dot gnu dot org
2006-06-21 15:43 ` rguenth at gcc dot gnu dot org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).