[Bug tree-optimization/115152] [13/14/15 Regression] wrong code at -O3 with "-fno-tree-fre -fno-tree-dominator-opts -fno-tree-loop-im" on x86_64-linux-gnu

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115152

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The bug is in strlen1:
```
maybe_invalidate called for MEM[(char *)&e] = vect_pretmp_76.13_77;
maybe_invalidate returns 1
maybe_invalidate called for MEM[(char *)&e] = vect_pretmp_89.18_79;
maybe_invalidate returns 1
Optimizing: pretmp_34 = e[0];
into: pretmp_34 = 0;
maybe_invalidate called for e[0] = pretmp_34;
  statement may clobber object &e 0 bytes in size
maybe_invalidate returns 1
maybe_invalidate called for c = _5;
maybe_invalidate returns 0
maybe_invalidate called for a = _54;
maybe_invalidate returns 0
maybe_invalidate called for b = 2;
maybe_invalidate returns 0
maybe_invalidate called for __builtin_abort ();
maybe_invalidate returns 0
pointer_query counters:
  index cache size:   0
  index entries:      0
  access cache size:  0
  access entries:     0
  hits:               0
  misses:             0
  failures:           0
  max_depth:          0
```