[PATCH] D88687: [InstCombine] visitTrunc - pass through undefs for trunc(shift(trunc/ext(x),c)) patterns

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon updated this revision to Diff 297832.
RKSimon edited the summary of this revision.
RKSimon added a comment.

Reworked with a Constant::mergeUndefsWith helper as suggested by @lebedev.ri


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D88687/new/

https://reviews.llvm.org/D88687

Files:
  llvm/include/llvm/IR/Constant.h
  llvm/lib/IR/Constants.cpp
  llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
  llvm/test/Transforms/InstCombine/cast.ll
  llvm/test/Transforms/InstCombine/trunc-shift-trunc.ll

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