TLI: Add addVectorizableFunctionsFromVecLib.

Also, add several entries to vectorizable functions table, and
corresponding tests. The table isn't complete, it'll be populated later.

Review: http://reviews.llvm.org/D8131

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232531 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed