http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58697
Bug ID: 58697 Summary: wrong code (segfaults) at -O3 Product: gcc Version: 4.8.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu GCC 4.8.1 miscompiles the following code on x86_64-linux at -O3 in 64-bit mode, resulting in a segfault. It doesn't seem to affect the current trunk and 4.7.x. It is related to 58653. $ gcc-4.8 -v Using built-in specs. COLLECT_GCC=gcc-4.8 COLLECT_LTO_WRAPPER=/usr/local/gcc-4.8/libexec/gcc/x86_64-unknown-linux-gnu/4.8.1/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.8.1/configure --enable-languages=c,c++,objc,obj-c++,fortran,lto --disable-checking --with-gmp=/usr/local/gcc-4.8 --with-mpfr=/usr/local/gcc-4.8 --with-mpc=/usr/local/gcc-4.8 --with-cloog=/usr/local/gcc-4.8 --prefix=/usr/local/gcc-4.8 Thread model: posix gcc version 4.8.1 (GCC) $ $ $ gcc-4.8 -O3 small.c; a.out Segmentation fault (core dumped) $ $ gcc-trunk -O3 small.c; a.out $ $ gcc-4.7 -O3 small.c; a.out $ -------------------------- int b, f, d[5][2]; unsigned int c; int main () { for (c = 0; c < 2; c++) if (d[b + 3][c] & d[b + 4][c]) if (f) break; return 0; }