http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57147
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> 2013-05-03 09:24:45 UTC --- Reduced testcase, miscompiles at -O. struct __jmp_buf_tag {}; typedef struct __jmp_buf_tag jmp_buf[1]; extern int _setjmp (struct __jmp_buf_tag __env[1]); jmp_buf g_return_jmp_buf; void SetNaClSwitchExpectations(void) { } void TestSyscall(void) { SetNaClSwitchExpectations(); _setjmp (g_return_jmp_buf); }