[PATCH] D83953: [HWLoops] Stop converting to a while loop when it would be unsafe to

[Sam Tebbs via Phabricator via llvm-commits]

samtebbs created this revision.
samtebbs added reviewers: samparker, SjoerdMeijer, dmgreen, t.p.northover, simon_tatham, olista01.
Herald added subscribers: llvm-commits, javed.absar, hiraditya.
Herald added a project: LLVM.

There are cases where a do-while loop would be converted to a while loop before finding out that it would be unsafe to expand the SCEV in this situation and then bailing out of hardware loop conversion.

This patch checks if it would be unsafe to expand the SCEV and if so stops converting the do-while into a while, allowing conversion to a hardware loop.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83953

Files:
  llvm/lib/CodeGen/HardwareLoops.cpp
  llvm/test/CodeGen/Thumb2/LowOverheadLoops/exitcount.ll

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