[llvm] [InstCombine] Use KnownBits predicate helpers (PR #115874)

[Yingwei Zheng via llvm-commits]

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@@ -6544,6 +6544,35 @@ bool InstCombinerImpl::replacedSelectWithOperand(SelectInst *SI,
   return false;
 }
 
+static std::optional<bool> compareKnownBits(ICmpInst::Predicate Pred,
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dtcxzyw wrote:

We already implemented similar logic in `CombinerHelper::matchICmpToTrueFalseKnownBits`. Do we need a common helper?


https://github.com/llvm/llvm-project/pull/115874