[PATCH] D107148: [InstCombine] Fold two-value clamp patterns

[Qiu Chaofan via Phabricator via llvm-commits]

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This patch is for PR43053 <https://bugs.llvm.org/show_bug.cgi?id=43053>, the following pattern:

  %cmp1 = icmp slt i32 %num, C1
  %s1 = select i1 %cmp1, i32 %num, i32 C1
  %cmp2 = icmp sgt i32 %s1, C2
  %r = select i1 %cmp2, i32 %s1, i32 C2
  ; C2 = C1 - 1

can be folded into

  %cmp3 = icmp sgt %num, C2
  %z = zext i1 %cmp3 to i32
  %r = add i32 %z, C2


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D107148

Files:
  llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
  llvm/test/Transforms/InstCombine/icmp-dom.ll
  llvm/test/Transforms/InstCombine/minmax-fold.ll

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