[llvm] [AMDGPU][SDAG] Support source modifiers on select integer operands (PR #147325)

[Matt Arsenault via llvm-commits]

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@@ -4830,6 +4830,52 @@ AMDGPUTargetLowering::foldFreeOpFromSelect(TargetLowering::DAGCombinerInfo &DCI,
   return SDValue();
 }
 
+static EVT getFloatVT(EVT VT) {
+  EVT FT = MVT::getFloatingPointVT(VT.getScalarSizeInBits());
+  return VT.isVector() ? VT.changeVectorElementType(FT) : FT;
+}
+
+static SDValue getBitwiseToSrcModifierOp(SDValue N,
+                                         TargetLowering::DAGCombinerInfo &DCI) {
+
+  unsigned Opc = N.getNode()->getOpcode();
+  if (Opc != ISD::AND && Opc != ISD::XOR && Opc != ISD::OR)
+    return SDValue();
+
+  SelectionDAG &DAG = DCI.DAG;
+  SDValue LHS = N->getOperand(0);
+  SDValue RHS = N->getOperand(1);
+  ConstantSDNode *CRHS = isConstOrConstSplat(RHS);
+
+  if (!CRHS)
+    return SDValue();
+
+  EVT VT = RHS.getValueType();
+  EVT FVT = getFloatVT(VT);
+  SDLoc SL = SDLoc(N);
+  SDValue BC = DAG.getNode(ISD::BITCAST, SL, FVT, LHS);
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arsenm wrote:

I'd just inline this into each of the uses instead of speculatively creating a node which may never be used 

https://github.com/llvm/llvm-project/pull/147325