The -O0 result looks right. This behavior observed on x86 using r157445 and
x64 using r157542.
reg...@john-home:~$ current-gcc -O0 small.c -o small -Wall
reg...@john-home:~$ ./small
1
reg...@john-home:~$ current-gcc -O1 small.c -o small -Wall
reg...@john-home:~$ ./small
0
reg...@john-home:~$ cat small.c
extern int printf (__const char *__restrict __format, ...);
static unsigned char g_2 = 1;
static int g_9;
static int *l_8 = &g_9;
static void func_12(int p_13)
{
int * l_17 = &g_9;
*l_17 &= 0 < p_13;
}
int main(void)
{
unsigned char l_11 = 254;
*l_8 |= g_2;
l_11 |= *l_8;
func_12(l_11);
printf("%d\n", g_9);
return 0;
}
reg...@john-home:~$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/home/regehr/z/compiler-install/gcc-r157445-install/libexec/gcc/i686-pc-linux-gnu/4.5.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/compiler-install/gcc-r157445-install
--program-prefix=r157445- --enable-languages=c,c++
Thread model: posix
gcc version 4.5.0 20100314 (experimental) (GCC)
--
Summary: possible wrong code bug
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: regehr at cs dot utah dot edu
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43438
