Currently SLP vectorizer tries to vectorize a binary operation and dies
immediately after unsuccessful the first unsuccessfull attempt. Patch
tries to improve the situation, trying to vectorize all binary
operations of all children nodes in the binop tree.
Differential Revision: https://reviews.llvm.org/D25517
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288115 91177308-0d34-0410-b5e6-96231b3b80d8