Add Rpass-missed and Rpass-analysis reports to the loop vectorizer. The remarks give...

Add Rpass-missed and Rpass-analysis reports to the loop vectorizer. The remarks give the vector width of vectorized loops and a brief analysis of loops that fail to be vectorized. For example, an analysis will be generated for loops containing control flow that cannot be simplified to a select. The optimization remarks also give the debug location of expressions that cannot be vectorized, for example the location of an unvectorizable call.

Reviewed by: Arnold Schwaighofer

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211721 91177308-0d34-0410-b5e6-96231b3b80d8