[Bug target/119428] [15 Regression] wrong code on e2fsprogs-1.47.2 since r15-8478-ge8a5f747cfa9c7

[slyfox at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119428

--- Comment #2 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Self-contained reproducer:

// $ cat bug.c
__attribute__((noipa, optimize(1)))
void bug_o1(unsigned int nr, void * addr)
{
        unsigned char   *ADDR = (unsigned char *) addr;

        ADDR += nr >> 3;
        *ADDR &= (unsigned char) ~(1 << (nr & 0x07));
}

__attribute__((noipa, optimize(2)))
void bug_o2(unsigned int nr, void * addr)
{
        unsigned char   *ADDR = (unsigned char *) addr;

        ADDR += nr >> 3;
        *ADDR &= (unsigned char) ~(1 << (nr & 0x07));
}

int main() {
  void * bmo1 = __builtin_malloc(1024);
  void * bmo2 = __builtin_malloc(1024);
  for (unsigned bno = 0; bno < 1024 * 8; ++bno) {
    __builtin_memset(bmo1, 0xff, 1024);
    __builtin_memset(bmo2, 0xff, 1024);
    bug_o1(bno, bmo1);
    bug_o2(bno, bmo2);
    if (__builtin_memcmp(bmo1, bmo2, 1024) != 0)
      __builtin_trap();
  }
}

$ gcc bug.c -o bug -O0 && ./bug
Illegal instruction (core dumped)