[PATCH] D67677: [InstCombine] dropRedundantMaskingOfLeftShiftInput(): pat. a/b with mask (PR42563)

[Sanjay Patel via Phabricator via llvm-commits]

spatel added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp:176-180
+      Type *ExtendedScalarTy = Type::getIntNTy(Ty->getContext(), 2 * BitWidth);
+      Type *ExtendedTy =
+          Ty->isVectorTy()
+              ? VectorType::get(ExtendedScalarTy, Ty->getVectorNumElements())
+              : ExtendedScalarTy;
----------------
Is there a test showing that we need this ext+trunc complexity?

See if I've botched this Alive somehow, but the simpler constant mask appears to work:
https://rise4fun.com/Alive/ArQC


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D67677/new/

https://reviews.llvm.org/D67677