[Bug middle-end/126363] New: fold_builtin_atomic_always_lock_free uses `INTVAL (expand_normal (arg0))` for INTEGER_CST

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126363

            Bug ID: 126363
           Summary: fold_builtin_atomic_always_lock_free uses `INTVAL
                    (expand_normal (arg0))` for INTEGER_CST
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: compile-time-hog, easyhack
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

The code in fold_builtin_atomic_always_lock_free does:

  if (TREE_CODE (arg0) != INTEGER_CST)
    return NULL_TREE;

  /* We need a corresponding integer mode for the access to be lock-free.  */
  size = INTVAL (expand_normal (arg0)) * BITS_PER_UNIT;


But should use tree_fits_shwi_p/tree_to_shwi instead.
That would be faster than going through expand.

Likewise this:
  if (TREE_CODE (arg1) == INTEGER_CST)
    {
      unsigned HOST_WIDE_INT val = UINTVAL (expand_normal (arg1));


Well this one should using ushwi instead.