https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107541

            Bug ID: 107541
           Summary: wrong code at -O1, -O2 and -O3 on x86_64-linux-gnu
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

This appears to be a recent regression; 12.2 compiles it correctly. 

Compiler Explorer: https://godbolt.org/z/6nq8jxn57

[661] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/13.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--enable-checking=yes --prefix=/local/suz-local/software/local/gcc-trunk
--enable-sanitizers --enable-languages=c,c++ --disable-werror --enable-multilib
--with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.0.0 20221104 (experimental) [master r13-3701-g07b0096e5b6] (GCC) 
[662] % 
[662] % gcctk -O0 small.c; ./a.out
[663] % 
[663] % gcctk -O1 small.c
[664] % ./a.out
Aborted
[665] % 
[665] % cat small.c
unsigned char a = 1;
char b, e;
long c;
short d;
int main() {
  a = ~(1 && a);
  c = ~((~a / 8 | -2) & 11007578330939886389LLU);
  e = -c;
  d = ~c / e;
  if (d < 2000)
    __builtin_abort();
  return 0;
}

Reply via email to