[Bug tree-optimization/58359] __builtin_unreachable prevents vectorization

[a.sinyavin at samsung dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58359

--- Comment #4 from Anatoly Sinyavin <a.sinyavin at samsung dot com> ---
Created attachment 30914
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30914&action=edit
Fisrt patch