[PATCH] D19258: Loop vectorization with induction variable with non-constant step.

[Elena Demikhovsky via llvm-commits]

delena updated this revision to Diff 55587.
delena added a comment.
Herald added a subscriber: sanjoy.

Following Hal's and Matthew comments, I keep Step as a SCEV inside InductionDescriptor. It allows to vectorize loop with induction variable with any *loop-invariant* step.
Again, we are talking about a "secondary" induction variable, which is being updated inside loop, but does not participate in trip count calculation.

I added one more example, where the step is a SCEV from outer loop:

  for (int j = 0; j < M; j++) {
    for (int i=0; i<N; i++){
      A[i] = x;
      x += j; // loop-invariant step
    }
  }


Repository:
  rL LLVM

http://reviews.llvm.org/D19258

Files:
  ../include/llvm/Transforms/Utils/LoopUtils.h
  ../lib/Transforms/Utils/LoopUtils.cpp
  ../lib/Transforms/Vectorize/LoopVectorize.cpp
  ../test/Transforms/LoopVectorize/induction-step.ll

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