[llvm] [InstCombine] Add transforms `(icmp spred (and X, Y), X)` if `X` or `Y` are known signed/unsigned (PR #94417)

[Yingwei Zheng via llvm-commits]

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@@ -4745,6 +4745,40 @@ static Instruction *foldICmpAndXX(ICmpInst &I, const SimplifyQuery &Q,
                           Constant::getNullValue(Op1->getType()));
   }
 
+  if (!ICmpInst::isSigned(Pred))
+    return nullptr;
+
+  KnownBits KnownY = IC.computeKnownBits(A, /*Depth=*/0, &I);
+  // (X & NegY) spred X --> (X & NegY) upred X
+  if (KnownY.isNegative())
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dtcxzyw wrote:

Can you double check that all cases are covered by existing tests?


https://github.com/llvm/llvm-project/pull/94417