[Bug target/19922] xor is enclosed in loop, and exectuted on each iteration of for statement

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19922

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So the question becomes do we care about this look if 
-fno-tree-loop-distribute-patterns  is added?  Anyways we are able to detect
the loop is a memset for a while now and then expand that to have no xor inside
the loop.