[PATCH] D64422: [SCEV] teach SCEV symbolical execution about overflow intrinsics folding.

[ChenZheng via Phabricator via llvm-commits]

shchenz created this revision.
shchenz added reviewers: nikic, sanjoy, hfinkel.
Herald added subscribers: llvm-commits, wuzish, javed.absar, hiraditya.
Herald added a project: LLVM.

Teach SCEV `computeExitCountExhaustively()` function about folding overflow intrinsics, so we can get trip count.

With this patch, we can get trip count smaller than `MaxBruteForceIterations` in `computeExitCountExhaustively()`.

SCEV should also be able to get loop trip count for overflow intrinsics loop even the trip count is bigger than the MaxBruteForceIterations(default value is 100). Need another patch for it.


https://reviews.llvm.org/D64422

Files:
  llvm/lib/Analysis/ConstantFolding.cpp
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/overflow-intrinsics-trip-count.ll

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