[Bug target/127012] Missed LLVM's or disjoint detection to lea for X86

[kaelfandrew at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127012

--- Comment #3 from Kael Franco <kaelfandrew at gmail dot com> ---
Partially fixed by r17-4953, e.g

unsigned
src_or (unsigned x, unsigned y)
{
  if ((x & 8) != 0)
    __builtin_unreachable ();

  return (x | 8);
}

emits
       leal    8(%rdi), %eax
       ret