[llvm-branch-commits] [llvm] [SelectionDAG] Handle constants in SimplifyMultipleUseDemandedBits (PR #224882)

Matt Arsenault via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Sun Sep 20 01:14:14 PDT 2026


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@@ -766,6 +766,12 @@ SDValue TargetLowering::SimplifyMultipleUseDemandedBits(
   unsigned BitWidth = DemandedBits.getBitWidth();
   KnownBits LHSKnown, RHSKnown;
   switch (Op.getOpcode()) {
+  case ISD::Constant: {
+    const APInt &Value = Op->getAsAPIntVal();
+    if (!Value.isZero() && (Value & DemandedBits).isZero())
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arsenm wrote:

Value.isSubsetOf(DemandedBits)? I think that's what the IR version does 

https://github.com/llvm/llvm-project/pull/224882


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