* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
@ 2014-02-24 8:37 ` rguenth at gcc dot gnu.org
2014-02-24 8:42 ` rguenth at gcc dot gnu.org
` (7 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-24 8:37 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |lto
Known to fail| |4.5.4, 4.6.4, 4.7.3
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, I can't reproduce this with 4.8 or trunk but with 4.5, 4.6 and 4.7.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
2014-02-24 8:37 ` [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu rguenth at gcc dot gnu.org
@ 2014-02-24 8:42 ` rguenth at gcc dot gnu.org
2014-02-24 9:00 ` su at cs dot ucdavis.edu
` (6 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-24 8:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
4.7 and lower is expected to show this behavior due to the bug that c++ is
not properly implemented as c = (char)((int)c + 1) and thus we think that
overflow is undefined.
4.8 and above has that fixed and thus shows different, working behavior.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
2014-02-24 8:37 ` [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu rguenth at gcc dot gnu.org
2014-02-24 8:42 ` rguenth at gcc dot gnu.org
@ 2014-02-24 9:00 ` su at cs dot ucdavis.edu
2014-02-24 9:20 ` rguenth at gcc dot gnu.org
` (5 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: su at cs dot ucdavis.edu @ 2014-02-24 9:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
--- Comment #3 from Zhendong Su <su at cs dot ucdavis.edu> ---
(In reply to Richard Biener from comment #1)
> Hmm, I can't reproduce this with 4.8 or trunk but with 4.5, 4.6 and 4.7.
Richard, it still fails for me. Did you use LTO?
$ 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 --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 4.9.0 20140223 (experimental) [trunk revision 208062] (GCC)
$
$ gcc-trunk -O0 -c foo.c
$ gcc-trunk -O0 -c main.c
$ gcc-trunk -Os foo.o main.o
$ a.out
$
$ gcc-trunk -flto -O0 -c foo.c
$ gcc-trunk -flto -O0 -c main.c
$ gcc-trunk -flto -Os foo.o main.o
$ a.out
^C
$
$ gcc-4.8 -flto -O0 -c foo.c
$ gcc-4.8 -flto -O0 -c main.c
$ gcc-4.8 -flto -Os foo.o main.o
$ a.out
^C
$
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2014-02-24 9:00 ` su at cs dot ucdavis.edu
@ 2014-02-24 9:20 ` rguenth at gcc dot gnu.org
2014-02-24 15:40 ` su at cs dot ucdavis.edu
` (4 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-24 9:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Zhendong Su from comment #3)
> (In reply to Richard Biener from comment #1)
> > Hmm, I can't reproduce this with 4.8 or trunk but with 4.5, 4.6 and 4.7.
>
> Richard, it still fails for me. Did you use LTO?
Yes, I did. For me -O[s23] -flto -v -save-temps -fdump-tree-all results
in a ccXYZ.ltrans0.o.169t.optimized file like
;; Function main (main, funcdef_no=2, decl_uid=2401, symbol_order=0) (executed
once)
main ()
{
<bb 2>:
return 0;
}
> $ 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 --prefix=/usr/local/gcc-trunk
> --enable-languages=c,c++ --disable-werror --enable-multilib
> Thread model: posix
> gcc version 4.9.0 20140223 (experimental) [trunk revision 208062] (GCC)
> $
> $ gcc-trunk -O0 -c foo.c
> $ gcc-trunk -O0 -c main.c
> $ gcc-trunk -Os foo.o main.o
> $ a.out
> $
> $ gcc-trunk -flto -O0 -c foo.c
> $ gcc-trunk -flto -O0 -c main.c
> $ gcc-trunk -flto -Os foo.o main.o
> $ a.out
> ^C
> $
> $ gcc-4.8 -flto -O0 -c foo.c
> $ gcc-4.8 -flto -O0 -c main.c
> $ gcc-4.8 -flto -Os foo.o main.o
> $ a.out
> ^C
> $
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2014-02-24 9:20 ` rguenth at gcc dot gnu.org
@ 2014-02-24 15:40 ` su at cs dot ucdavis.edu
2014-02-24 16:36 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: su at cs dot ucdavis.edu @ 2014-02-24 15:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
--- Comment #5 from Zhendong Su <su at cs dot ucdavis.edu> ---
Did you separately compile the two files at -O0 and link at -Os, like below?
> $ gcc-trunk -flto -O0 -c foo.c
> $ gcc-trunk -flto -O0 -c main.c
> $ gcc-trunk -flto -Os foo.o main.o
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2014-02-24 15:40 ` su at cs dot ucdavis.edu
@ 2014-02-24 16:36 ` rguenth at gcc dot gnu.org
2014-02-24 17:01 ` rguenth at gcc dot gnu.org
` (2 subsequent siblings)
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-24 16:36 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-02-24
Ever confirmed|0 |1
--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Zhendong Su from comment #5)
> Did you separately compile the two files at -O0 and link at -Os, like below?
>
> > $ gcc-trunk -flto -O0 -c foo.c
> > $ gcc-trunk -flto -O0 -c main.c
> > $ gcc-trunk -flto -Os foo.o main.o
Ah, no. The issue here is that the fix for that bug I mention triggers
on TYPE_OVERFLOW_UNDEFINED, but with -O[01] we have -fno-strict-overflow
enabled and thus we lower it in a bogus way while with -O[s23] we
have -fstrict-overflow. This is a IL semantic change that is not actually
contained in the IL ...
Anyway, confirmed.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (5 preceding siblings ...)
2014-02-24 16:36 ` rguenth at gcc dot gnu.org
@ 2014-02-24 17:01 ` rguenth at gcc dot gnu.org
2014-02-25 8:58 ` rguenth at gcc dot gnu.org
2014-02-25 9:00 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-24 17:01 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Note that such bugs may occur generally when mixing -O[01] with -O[s23] ... for
a similar case, -f[no-]strict-aliasing we get away with streaming get_alias_set
() == 0.
Thus I think we have to "conservatively" merge -fstrict-overflow, similar
to how we treat -ffp-contract.
I have a patch.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (6 preceding siblings ...)
2014-02-24 17:01 ` rguenth at gcc dot gnu.org
@ 2014-02-25 8:58 ` rguenth at gcc dot gnu.org
2014-02-25 9:00 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-25 8:58 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue Feb 25 08:57:42 2014
New Revision: 208112
URL: http://gcc.gnu.org/viewcvs?rev=208112&root=gcc&view=rev
Log:
2014-02-25 Richard Biener <rguenther@suse.de>
PR lto/60319
* lto-opts.c (lto_write_options): Output non-explicit conservative
-fwrapv, -fno-trapv and -fno-strict-overflow.
* lto-wrapper.c (merge_and_complain): Handle merging those options.
(run_gcc): And pass them through.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/lto-opts.c
trunk/gcc/lto-wrapper.c
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug lto/60319] wrong code (that hangs) by LTO at -Os and above on x86_64-linux-gnu
[not found] <bug-60319-4@http.gcc.gnu.org/bugzilla/>
` (7 preceding siblings ...)
2014-02-25 8:58 ` rguenth at gcc dot gnu.org
@ 2014-02-25 9:00 ` rguenth at gcc dot gnu.org
8 siblings, 0 replies; 9+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-02-25 9:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60319
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed for 4.9.0.
^ permalink raw reply [flat|nested] 9+ messages in thread