[Bug tree-optimization/110666] [14 Regression] wrong code at -O1 and above on x86_64-linux-gnu

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110666

--- Comment #5 from Zhendong Su <zhendong.su at inf dot ethz.ch> ---
A couple of very likely related tests (especially #2 and #3):

*** (1) wrong code at -O2, -O3, and -Os

[539] % gcctk -O1 small.c; ./a.out
[540] % gcctk -O2 small.c
[541] % timeout -s 9 5 ./a.out
Killed
[542] % cat small.c
int a, b = -1, c, d = -1;
int main() {
  if (a)
    goto L2;
 L1:
  a = 0;
 L2:
  b && c;
  c = ~c * (d ^ (0 || a) || d & b);
  if (c)
    goto L1;
  return 0;
}

*** (2) wrong code at -O1 and above

[558] % gcctk -O0 small.c; ./a.out
[559] % gcctk -O1 small.c
[560] % ./a.out
Floating point exception
[561] % cat small.c
int a = 1, b, c;
void f(int d) {
  for (; c < 2; c++) {
    if (!a)
      b = -1;
    a = (d != 4) == d;
    b = 1 % ~b;
  }
}
int main() { f(1 || b); }

*** (3) wrong code at -O1 and above

[577] % gcctk -O0 small.c; ./a.out
[578] % gcctk -O1 small.c
[579] % timeout -s 9 5 ./a.out
Killed
[580] % cat small.c
int a = 1, b, c, d;
void e(int f) {
  for (; c < 2; c++) {
    if (b)
      d = c;
    c = d;
    b = f;
  }
}
int main() { e(((a != 2) != a) != 1); }