https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80541
Bug ID: 80541 Summary: Wrong constant folding Product: gcc Version: 7.0.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: ishiura-compiler at ml dot kwansei.ac.jp Target Milestone: --- GCC 7.0.1 for x86_64 miscompiles the following code. Reproduces on gcc-4.6.4 or later with -O2, -O3 and -Os. % cat test.c int main (void) { volatile int a = 0; int b = -( a == 0 ); int x = 1 % ( b + ( b * 0x7fffffffffffffff ) + 0x7fffffffffffffff ); if (x != 0) __builtin_abort(); return 0; } % gcc-7.0 test.c -O2 % ./a.out zsh: abort (core dumped) ./a.out % gcc-7.0 test.c -O3 % ./a.out zsh: abort (core dumped) ./a.out % gcc-7.0 test.c -Os % ./a.out zsh: abort (core dumped) ./a.out % gcc-7.0 -v Using built-in specs. COLLECT_GCC=gcc-7.0 COLLECT_LTO_WRAPPER=/home/cappie/opt/gcc-7.0.1/libexec/gcc/x86_64-pc-linux-gnu/7.0.1/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../configure --prefix=/home/cappie/opt/gcc-7.0.1 --disable-nls --disable-multilib --program-suffix=-7.0 --enable-languages=c Thread model: posix gcc version 7.0.1 20170405 (experimental) (GCC)