[PATCH] D147597: [InstCombine] icmp(X | LHS, C) --> icmp(X, 0)

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp:1957
+  const APInt *LHS;
+  // icmp(X | LHS, C) --> icmp(X, 0)
+  if (C.isNonNegative() && match(Or, m_c_Or(m_Value(X), m_APInt(LHS)))) {
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Why is a constant that occurs on the RHS called LHS?


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Comment at: llvm/test/Transforms/InstCombine/icmp.ll:4633
 ; CHECK-LABEL: @mul_or_positive_sgt_zero(
 ; CHECK-NEXT:    [[MUL1:%.*]] = mul i8 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[MUL1]], -1
----------------
What's the purpose of the mul instruction in all these tests? It doesn't seem related?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D147597/new/

https://reviews.llvm.org/D147597