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* [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu
@ 2015-09-30 16:21 su at cs dot ucdavis.edu
2015-09-30 17:12 ` [Bug rtl-optimization/67787] [6 Regression] " mpolacek at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: su at cs dot ucdavis.edu @ 2015-09-30 16:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67787
Bug ID: 67787
Summary: wrong code at -O3 on x86_64-linux-gnu
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
Target Milestone: ---
The current gcc trunk miscompiles the following code on x86_64-linux-gnu at -O3
in both 32-bit and 64-bit modes.
This is a regression from 5.2.x.
I wasn't able to get rid of the call to printf.
$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-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 6.0.0 20150930 (experimental) [trunk revision 228291] (GCC)
$
$ gcc-trunk -O2 small.c; ./a.out
$
$ gcc-5.2 -O3 small.c; ./a.out
$
$
$ gcc-trunk -O3 small.c
$ ./a.out
Aborted
$
----------------------------------------------------
int printf (const char *, ...);
int a, c, f, g;
char b;
static int
fn1 ()
{
char h;
int k = -1, i, j;
for (; b < 16; b++)
;
printf (" ");
if (b < 5)
k++;
if (k)
{
int l = 2;
a = h = b < 0 || b > (127 >> l) ? b : b << 1;
return 0;
}
for (i = 0; i < 1; i++)
for (j = 0; j < 7; j++)
f = 0;
for (c = 0; c; c++)
;
if (g)
for (;;)
;
return 0;
}
int
main ()
{
fn1 ();
if (a != 32)
__builtin_abort ();
return 0;
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/67787] [6 Regression] wrong code at -O3 on x86_64-linux-gnu
2015-09-30 16:21 [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
@ 2015-09-30 17:12 ` mpolacek at gcc dot gnu.org
2015-09-30 17:20 ` ktkachov at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-09-30 17:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67787
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2015-09-30
CC| |ktkachov at gcc dot gnu.org,
| |mpolacek at gcc dot gnu.org
Target Milestone|--- |6.0
Summary|wrong code at -O3 on |[6 Regression] wrong code
|x86_64-linux-gnu |at -O3 on x86_64-linux-gnu
Ever confirmed|0 |1
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r228194.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/67787] [6 Regression] wrong code at -O3 on x86_64-linux-gnu
2015-09-30 16:21 [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
2015-09-30 17:12 ` [Bug rtl-optimization/67787] [6 Regression] " mpolacek at gcc dot gnu.org
@ 2015-09-30 17:20 ` ktkachov at gcc dot gnu.org
2015-10-02 8:37 ` ktkachov at gcc dot gnu.org
2015-10-02 8:39 ` ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2015-09-30 17:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67787
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |ktkachov at gcc dot gnu.org
Known to fail| |6.0
--- Comment #2 from ktkachov at gcc dot gnu.org ---
Confirmed. I have a patch in testing.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/67787] [6 Regression] wrong code at -O3 on x86_64-linux-gnu
2015-09-30 16:21 [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
2015-09-30 17:12 ` [Bug rtl-optimization/67787] [6 Regression] " mpolacek at gcc dot gnu.org
2015-09-30 17:20 ` ktkachov at gcc dot gnu.org
@ 2015-10-02 8:37 ` ktkachov at gcc dot gnu.org
2015-10-02 8:39 ` ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2015-10-02 8:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67787
--- Comment #3 from ktkachov at gcc dot gnu.org ---
Author: ktkachov
Date: Fri Oct 2 08:36:45 2015
New Revision: 228375
URL: https://gcc.gnu.org/viewcvs?rev=228375&root=gcc&view=rev
Log:
[RTL ifcvt] PR 67786, 67787: Check that intermediate instructions in the basic
block don't clobber a reg used in condition
PR rtl-optimization/67786
PR rtl-optimization/67787
* ifcvt.c (bb_valid_for_noce_process_p): Reject basic block if
it modifies a reg used in the condition calculation.
* gcc.dg/pr67786.c: New test.
* gcc.dg/pr67787.c: Likewise.
Added:
trunk/gcc/testsuite/gcc.dg/pr67786.c
trunk/gcc/testsuite/gcc.dg/pr67787.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/ifcvt.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/67787] [6 Regression] wrong code at -O3 on x86_64-linux-gnu
2015-09-30 16:21 [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
` (2 preceding siblings ...)
2015-10-02 8:37 ` ktkachov at gcc dot gnu.org
@ 2015-10-02 8:39 ` ktkachov at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ktkachov at gcc dot gnu.org @ 2015-10-02 8:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67787
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from ktkachov at gcc dot gnu.org ---
Fixed on trunk.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-10-02 8:39 UTC | newest]
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2015-09-30 16:21 [Bug rtl-optimization/67787] New: wrong code at -O3 on x86_64-linux-gnu su at cs dot ucdavis.edu
2015-09-30 17:12 ` [Bug rtl-optimization/67787] [6 Regression] " mpolacek at gcc dot gnu.org
2015-09-30 17:20 ` ktkachov at gcc dot gnu.org
2015-10-02 8:37 ` ktkachov at gcc dot gnu.org
2015-10-02 8:39 ` ktkachov at gcc dot gnu.org
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