[Bug tree-optimization/111167] swapping around duplicated conditionals can produce better code

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111167

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
In this case the problem seems to be jump threading related.

If we did:
```
void f(int);
void lookup_attribute1(const char *attr_ns, int list, int t) {
  short t1;
  if (attr_ns)  { if (list) {t1 = 0; goto L1;} return; }
  if (list){t1 = t;goto L1;} else return;
L1:
  f(t1);
}
```

I Notice clang does not do this either even though the original testcase seems
ok.