[all-commits] [llvm/llvm-project] a56280: [LV] Avoid needless fold tail

[Gil Rapaport via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a56280094e08792516b035390a946ea337a27b97
      https://github.com/llvm/llvm-project/commit/a56280094e08792516b035390a946ea337a27b97
  Author: Gil Rapaport <gil.rapaport at intel.com>
  Date:   2020-12-22 (Tue, 22 Dec 2020)

  Changed paths:
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    A llvm/test/Transforms/LoopVectorize/dont-fold-tail-for-const-TC.ll
    A llvm/test/Transforms/LoopVectorize/dont-fold-tail-for-divisible-TC.ll

  Log Message:
  -----------
  [LV] Avoid needless fold tail

When the trip-count is provably divisible by the maximal/chosen VF, folding the
loop's tail during vectorization is redundant. This commit extends the existing
test for constant trip-counts to any trip-count known to be divisible by
maximal/selected VF by SCEV.

Differential Revision: https://reviews.llvm.org/D93615