Vectorizer: Add support for loop reductions.

For example:

  for (i=0; i<n; i++)
   sum += A[i] +  B[i] + i;



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166351 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed