[PATCH] D152772: [LoopSink] Allow sinking to PHI-use

[Wenlei He via Phabricator via llvm-commits]

wenlei created this revision.
wenlei added reviewers: nikic, asbirlea, reames.
Herald added subscribers: wlei, StephenFan, hoy, modimo, hiraditya.
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This change allows sinking defs from loop preheader with PHI-use into loop body. Loop sink can now see through PHI-use and select incoming blocks of value being used as candidate sink destination.

It makes loop sink more effective so more LICM can be undone if proven unprofitable with profile info. It addresses the motivating case in D87551 <https://reviews.llvm.org/D87551>, without resorting to profile guided LICM which breaks canonicalization.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D152772

Files:
  llvm/lib/Transforms/Scalar/LoopSink.cpp
  llvm/test/Transforms/LICM/loopsink-phi.ll

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