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* [Bug tree-optimization/61434] New: wrong code at -O3 on x86_64-linux
@ 2014-06-06 22:24 su at cs dot ucdavis.edu
2014-11-19 13:47 ` [Bug tree-optimization/61434] [5 Regression] " rguenth at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: su at cs dot ucdavis.edu @ 2014-06-06 22:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61434
Bug ID: 61434
Summary: wrong code at -O3 on x86_64-linux
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 miscompiles the following code on x86_64-linux at -O3 in
both 32-bit and 64-bit modes.
This is a regression from 4.9.x. The issue seems to be in the tree vectorizer
as the reported test does not fail with -fno-tree-vectorize.
$ 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/4.10.0/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 4.10.0 20140606 (experimental) [trunk revision 211299] (GCC)
$
$ gcc-trunk -O2 small.c; a.out
$ gcc-trunk -fno-tree-vectorize -O3 small.c; a.out
$ gcc-4.9.0 -O3 small.c; a.out
$
$ gcc-trunk -O3 small.c
$ a.out
Aborted (core dumped)
$
-----------------------------
int a, b[2], c, d, e, f, g;
struct
{
int f1:1;
int f2:1;
} w;
void
fn1 (int p1, int p2)
{
// does nothing
}
int
main ()
{
b[1] = 1;
for (; f < 1; f++)
{
w.f2 = 0;
if (w.f1)
fn1 (e++, a++ && d++);
}
for (; g < 1; g++)
c = b[a];
if (c != 0)
__builtin_abort ();
return 0;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug tree-optimization/61434] [5 Regression] wrong code at -O3 on x86_64-linux
2014-06-06 22:24 [Bug tree-optimization/61434] New: wrong code at -O3 on x86_64-linux su at cs dot ucdavis.edu
@ 2014-11-19 13:47 ` rguenth at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-11-19 13:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61434
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Version|unknown |5.0
Resolution|--- |FIXED
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Seems to be fixed.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-06-06 22:24 [Bug tree-optimization/61434] New: wrong code at -O3 on x86_64-linux su at cs dot ucdavis.edu
2014-11-19 13:47 ` [Bug tree-optimization/61434] [5 Regression] " rguenth at gcc dot gnu.org
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