reg...@john-home:~$ current-gcc -v Using built-in specs. COLLECT_GCC=current-gcc COLLECT_LTO_WRAPPER=/home/regehr/z/tmp/gcc-r155465-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/tmp/gcc-r155465-install --program-prefix=r155465- --enable-languages=c,c++ Thread model: posix gcc version 4.5.0 20091225 (experimental) (GCC) reg...@john-home:~$ current-gcc -O2 small.c -o small reg...@john-home:~$ ./small g_3 = -1 reg...@john-home:~$ current-gcc -O3 small.c -o small reg...@john-home:~$ ./small g_3 = 255 reg...@john-home:~$ cat small.c #include <stdio.h>
int g_3; int main (void) { long long l_2; for (l_2 = -1; l_2 != 0; l_2 = (unsigned char)(l_2 - 1)) { g_3 |= l_2; } printf("g_3 = %d\n", g_3); return 0; } -- Summary: possible integer 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=42512