[Bug tree-optimization/64193] [4.8/4.9/5 Regression] Decreased performance after r173250

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64193

--- Comment #7 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
AFAICT if there is any speedup with the patch in comment 5, it is negligible on
a 2.8Ghz Corei7 and x86_64-apple-darwin14: ~7.1s with/without the patch. Note
that the timing in the test is not very precise.