[llvm] [DAGCombiner] Add support for scalarising extracts of a vector setcc (PR #116031)

[Paul Walker via llvm-commits]

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@@ -22743,14 +22743,20 @@ SDValue DAGCombiner::scalarizeExtractedVectorLoad(SDNode *EVE, EVT InVecVT,
 
 /// Transform a vector binary operation into a scalar binary operation by moving
 /// the math/logic after an extract element of a vector.
-static SDValue scalarizeExtractedBinop(SDNode *ExtElt, SelectionDAG &DAG,
-                                       const SDLoc &DL, bool LegalOperations) {
+static SDValue scalarizeExtractedBinOp(SDNode *ExtElt, SelectionDAG &DAG,
+                                       const SDLoc &DL) {
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   SDValue Vec = ExtElt->getOperand(0);
   SDValue Index = ExtElt->getOperand(1);
   auto *IndexC = dyn_cast<ConstantSDNode>(Index);
-  if (!IndexC || !TLI.isBinOp(Vec.getOpcode()) || !Vec.hasOneUse() ||
-      Vec->getNumValues() != 1)
+  if (!IndexC ||
+      (!TLI.isBinOp(Vec.getOpcode()) && Vec.getOpcode() != ISD::SETCC) ||
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paulwalker-arm wrote:

`Vec.getOpcode()` is used four times so perhaps worth pulling out?

https://github.com/llvm/llvm-project/pull/116031