[Bug tree-optimization/99751] New: wrong code at -O1

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99751

            Bug ID: 99751
           Summary: wrong code at -O1
           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: ---

[549] % 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/11.0.1/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 11.0.1 20210324 (experimental) [master revision
be70bb5e4ba:220fd7ed5f2:bf1f3168f474734400e7a97660d1e7dec664bca9] (GCC) 
[550] % 
[550] % gcctk -O0 small.c; ./a.out
[551] % 
[551] % gcctk -O1 small.c
[552] % ./a.out
Aborted
[553] % 
[553] % cat small.c
int *a, **c = &a;
int *b(int *d) { return d; }
void e(int *d) { *c = b(d); }
int main() {
  int f = (e(&f), 0);
  if (a != &f)
    __builtin_abort();
  return 0;
}