[PATCH] D106010: [SimplifyCFG] Rerun PHI deduplication after common code sinkinkg (PR51092)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: RKSimon, spatel.
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`SinkCommonCodeFromPredecessors()` doesn't itself ensure that duplicate PHI nodes aren't created.
I suppose, we could teach it to do that on-the-fly (& account for the already-existing PHI nodes,
& adjust costmodel), the diff will be bigger than this.

The alternative is to schedule a new EarlyCSE pass invocation somewhere later in the pipeline.
Clearly, we don't have any EarlyCSE runs in module optimization passline, so this pattern isn't cleaned up...


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D106010

Files:
  llvm/lib/Transforms/Utils/SimplifyCFG.cpp
  llvm/test/Transforms/PhaseOrdering/X86/earlycse-after-simplifycfg-two-entry-phi-node-folding.ll
  llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll

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