[PATCH] D28044: [LV/LoopAccess] Check statically if an unknown dependence distance can be proven larger than the loop-count

[Dorit Nuzman via Phabricator via llvm-commits]

dorit created this revision.
dorit added reviewers: mkuper, silviu.baranga.
dorit added a subscriber: llvm-commits.
Herald added a subscriber: mzolotukhin.

This fixes PR31098: Try to resolve statically data-dependences whose compile-time-unknown distance can be proven larger than the loop-count, instead of resorting to runtime dependence checking (which are not always possible).

(A couple existing testcases assumed that runtime tests will be generated, but with this patch the runtime tests are no longer generated because a dependence with an unknown distance is resolved statically; I changed the loop-count in these tests so that we will not be able to resolve the dependence statically; This way these tests can continue to verify that the runtime tests can be created for the accesses at hand.)


https://reviews.llvm.org/D28044

Files:
  llvm/lib/Analysis/LoopAccessAnalysis.cpp
  llvm/test/Analysis/LoopAccessAnalysis/multiple-strides-rt-memory-checks.ll
  llvm/test/Transforms/LoopVectorize/multiple-strides-vectorization.ll
  llvm/test/Transforms/LoopVectorize/pr31098.ll

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