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[Bug tree-optimization/58732] New: wrong code at -O3 on x86_64-linux-gnu
- From: "su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 15 Oct 2013 03:43:21 +0000
- Subject: [Bug tree-optimization/58732] New: wrong code at -O3 on x86_64-linux-gnu
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58732
Bug ID: 58732
Summary: wrong code at -O3 on x86_64-linux-gnu
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: su at cs dot ucdavis.edu
The attached testcase is miscompiled by gcc 4.8.1 on x86_64-linux-gnu at -O3 in
both 32-bit and 64-bit modes.
It does not seem to affect the current gcc trunk, 4.6.x, and 4.7.x.
$ gcc-4.8 -v
Using built-in specs.
COLLECT_GCC=gcc-4.8
COLLECT_LTO_WRAPPER=/usr/local/gcc-4.8/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-4.8.1/configure
--enable-languages=c,c++,objc,obj-c++,fortran,lto --disable-checking
--with-gmp=/usr/local/gcc-4.8 --with-mpfr=/usr/local/gcc-4.8
--with-mpc=/usr/local/gcc-4.8 --with-cloog=/usr/local/gcc-4.8
--prefix=/usr/local/gcc-4.8
Thread model: posix
gcc version 4.8.1 (GCC)
$
$ gcc-4.8 -O2 small.c; a.out
$
$ gcc-4.8 -O3 small.c; a.out
Aborted (core dumped)
$
$ gcc-trunk -O3 small.c; a.out
$ gcc-4.6 -O3 small.c; a.out
$ gcc-4.7 -O3 small.c; a.out
$
--------------------------------
static int a = -1, c, d;
int b[10];
int
main ()
{
for (d = 1; d >= 0; d--)
{
b[8] = 0;
for (c = 0; c; c++)
;
b[d+8] = a;
}
if (b[8] != -1)
__builtin_abort();
return 0;
}