https://gcc.gnu.org/bugzilla/show_bug.cgi?id=73450
Bug ID: 73450 Summary: wrong code at -Os and above on x86_64-linux-gnu in both 32-bit and 64-bit modes (executable hangs) Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: chengniansun at gmail dot com Target Milestone: --- $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160810 (experimental) [trunk revision 239341] (GCC) $ gcc-trunk small.c -O1 ; timeout -s 9 1 ./a.out $ gcc-trunk small.c -Os ; timeout -s 9 1 ./a.out Killed $ gcc-trunk small.c -O3 ; timeout -s 9 1 ./a.out Killed $ cat small.c int a; char b; int main() { char c = 0; for (; c != 3; c = c + 7) { a = b & a; if (a) break; } return 0; } $