[Bug tree-optimization/118514] New: wrong code at -O{1,s,3} on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118514

            Bug ID: 118514
           Summary: wrong code at -O{1,s,3} 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: ---

It appears to be a recent regression from 14.2. 

Compiler Explorer: https://godbolt.org/z/nPev9oj1x

[635] % 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/15.0.1/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
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.1 20250116 (experimental) (GCC) 
[636] % 
[636] % gcctk -O1 small.c
[637] % ./a.out
Segmentation fault
[638] % 
[638] % cat small.c
int a, c = 1;
unsigned char b[1], d;
void __assert_fail();
int main() {
  while (a || !c) {
    char e = b[1000000000];
    d = e < 0 || b[1000000000] > 1;
    if (d)
      __assert_fail();
  }
  return 0;
}