http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57829
Bug ID: 57829
Summary: Wrong constant folding
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.7.2 - 4.9.0 for i686 and x86_64 miscompiles the following code.
$ cat error.c
int main (void)
{
volatile int k = 1;
int t = 2 | ( ( k - 1) >> 31 );
if (t != 2) __builtin_abort();
return 0;
}
$ x86_64-unknown-linux-gnu-gcc-4.9.0 error.c -O1
$ ./a.out
Aborted (core dumped)
$ x86_64-unknown-linux-gnu-gcc-4.9.0 -v
Using built-in specs.
COLLECT_GCC=x86_64-unknown-linux-gnu-gcc-4.9.0
COLLECT_LTO_WRAPPER=/usr/local/x86_64-tools/gcc-4.9.0/libexec/gcc/x86_64-unknown-linux-gnu/4.9.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /home/hassy/gcc/configure
--prefix=/usr/local/x86_64-tools/gcc-4.9.0/
--with-gmp=/usr/local/gmp-5.1.1/ --with-mpfr=/usr/local/mpfr-3.1.2/
--with-mpc=/usr/local/mpc-1.0.1/ --disable-multilib --disable-nls
--enable-languages=c
Thread model: posix
gcc version 4.9.0 20130704 (experimental) (GCC)
The status of the other versions are as follows:
(x86_64)
GCC-4.7.2 Error
GCC-4.8.2 (prerelease) OK
GCC-4.9.0 (experimental) Error
(i686)
GCC-4.7.2 Error
GCC-4.8.2 (prerelease) Error
GCC-4.9.0 (experimental) Error
