[Bug tree-optimization/97764] New: wrong code at -O1 and above on x86_64-pc-linux-gnu

[zhendong.su at inf dot ethz.ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97764

            Bug ID: 97764
           Summary: wrong code at -O1 and above on x86_64-pc-linux-gnu
           Product: gcc
           Version: 11.0
            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: ---

[514] % 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/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20201109 (experimental) [master revision
946b73c1132:a700e491347:dc7e8839c92c4bc3c3741cf27b0af81edb803fe7] (GCC) 
[515] % 
[515] % gcctk -O0 small.c; ./a.out
[516] % 
[516] % gcctk -O1 small.c
[517] % ./a.out
Aborted
[518] % 
[518] % cat small.c
struct S {
  int b : 3;
  int c : 28;
  int d : 1;
};

int main() {
  struct S e = {1, -1};
  if (e.d)
    __builtin_abort();
  return 0;
}