https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70780
Bug ID: 70780 Summary: wrong code at -O2 and -O3 on x86_64-linux-gnu Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- The current gcc trunk miscompiles the following code on x86_64-linux-gnu at -O2 and -O3 in both 32-bit and 64-bit modes. This is a regression from 5.3.x. $ 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 20160424 (experimental) [trunk revision 235394] (GCC) $ $ gcc-trunk -Os small.c; ./a.out $ gcc-5.3 -O2 small.c; ./a.out $ $ gcc-trunk -O2 small.c $ ./a.out Segmentation fault (core dumped) $ -------------------------------- int a, b, c, *d, e; static int fn1 () { if (a) goto l1; l2: while (b) if (*d) return c; for (e = 0; e; e++) { goto l2; l1:; } return 0; } int main () { fn1 (); return 0; }