[PATCH] Add #pragma vectorize enable/disable to LLVM

[Arnold Schwaighofer]

  We do need the barrier noop pass to break out of the CallGraph SCC pass manager before the loop vectorizer.

  + MPM.add(createBarrierNoopPass());
  + MPM.add(createLoopVectorizePass(DisableUnrollLoops, LoopVectorize));

  Otherwise, LGTM.

http://llvm-reviews.chandlerc.com/D2328