[PATCH] D124897: Extend switch condition in optimizeSwitchPhiConst when free

[Matthias Braun via Phabricator via llvm-commits]

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In a case like:

  switch((i32)x) { case 42: phi((i64)42, ...); }

replace `(i64)42` with `zext(x)` when we can do so for free.

This fixes a part of https://github.com/llvm/llvm-project/issues/55153


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D124897

Files:
  llvm/lib/CodeGen/CodeGenPrepare.cpp
  llvm/test/CodeGen/X86/switch-phi-const.ll
  llvm/test/Transforms/CodeGenPrepare/X86/switch-phi-const.ll

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