https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71691
Bug ID: 71691 Summary: wrong code at -O3 in both 32-bit and 64-bit modes on x86_64-linux-gnu (Floating point exception) Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization 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 20160628 (experimental) [trunk revision 237830] (GCC) $ $ gcc-trunk -O3 -m32 small.c ; ./a.out Floating point exception (core dumped) $ $ gcc-trunk -O3 -m64 small.c ; ./a.out Floating point exception (core dumped) $ $ gcc-trunk -O2 -m64 small.c ; ./a.out $ $ cat small.c char b; short f; unsigned e; int g = 20; void fn1() { int l = 0; for (; l <= 7; l++) { int h, j = 38; if (g) h = 0; for (; h <= 7; h++) { int i, k = b % (j % 4); g = f; for (;;) { j = 6 || b; if (e) { for (; j; --j) if (k) __builtin_printf("%d", 9); if (i) __builtin_printf("%d", j); } if (l) continue; break; } i = f || b; } } } int main() { fn1(); return 0; } $