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* [Bug tree-optimization/58832] New: wrong code at -O2 and -O3 on x86_64-linux-gnu in 64-bit mode
@ 2013-10-22 1:38 su at cs dot ucdavis.edu
2013-10-23 8:18 ` [Bug tree-optimization/58832] [4.9 Regression] " rguenth at gcc dot gnu.org
2013-10-25 10:14 ` rguenth at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: su at cs dot ucdavis.edu @ 2013-10-22 1:38 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58832
Bug ID: 58832
Summary: wrong code at -O2 and -O3 on x86_64-linux-gnu in
64-bit mode
Product: gcc
Version: 4.9.0
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 -O2 and
-O3 in 64-bit mode.
This is a regression from 4.8.x and may be related to 58831, which also affects
gcc 4.8.x though.
$ 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 --disable-werror
--enable-checking=release --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 20131021 (experimental) [trunk revision 203907] (GCC)
$
$ gcc-trunk -m64 -O1 small.c; a.out
$ gcc-trunk -m32 -O2 small.c; a.out
$ gcc-4.8.2 -m64 -O2 small.c; a.out
$ gcc-4.7.3 -m64 -O2 small.c; a.out
$
$ gcc-trunk -m64 -O2 small.c; a.out
a.out: small.c:9: fn1: Assertion `d || (1 & e)' failed.
Aborted (core dumped)
$ gcc-trunk -m64 -O3 small.c; a.out
a.out: small.c:9: fn1: Assertion `d || (1 & e)' failed.
Aborted (core dumped)
$
$
---------------------------------
#include<assert.h>
int a, b, c, *d, e, g;
void
fn1 (int *p1, int **p2)
{
*p2 = &g;
assert (d || (1 & e));
}
static int **
fn2 ()
{
int *f = &b;
for (; c; c--)
f = 0;
assert(a || f);
return 0;
}
static unsigned short
fn3 ()
{
fn2 ();
fn1 (0, &d);
return 0;
}
int
main ()
{
fn2 ();
fn3 ();
return 0;
}
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-10-22 1:38 [Bug tree-optimization/58832] New: wrong code at -O2 and -O3 on x86_64-linux-gnu in 64-bit mode su at cs dot ucdavis.edu
2013-10-23 8:18 ` [Bug tree-optimization/58832] [4.9 Regression] " rguenth at gcc dot gnu.org
2013-10-25 10:14 ` rguenth at gcc dot gnu.org
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