[PATCH] D116930: [DAGCombine] Fold SRA of a load into a narrower sign-extending load

[Bjorn Pettersson via Phabricator via llvm-commits]

bjope created this revision.
bjope added reviewers: RKSimon, samparker, nemanjai.
Herald added subscribers: ecnelises, pengfei, hiraditya.
bjope requested review of this revision.
Herald added a project: LLVM.

An sra is basically sign-extending a narrower value. Fold away the
shift by doing a sextload of a narrower value, when it is legal to
reduce the load width accordingly.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D116930

Files:
  llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
  llvm/test/CodeGen/PowerPC/pr13891.ll
  llvm/test/CodeGen/X86/combine-sra-load.ll

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