[llvm] [DAG] Refactor X86 combineVSelectWithAllOnesOrZeros fold into a generic DAG Combine (PR #145298)

[via llvm-commits]

================
@@ -12945,6 +12945,85 @@ SDValue DAGCombiner::visitVP_SELECT(SDNode *N) {
   return SDValue();
 }
 
+static SDValue combineVSelectWithAllOnesOrZeros(SDValue Cond, SDValue TVal,
+                                                SDValue FVal,
+                                                const TargetLowering &TLI,
+                                                SelectionDAG &DAG,
+                                                const SDLoc &DL) {
+  if (!TLI.isTypeLegal(TVal.getValueType()))
+    return SDValue();
+
+  EVT VT = TVal.getValueType();
+  EVT CondVT = Cond.getValueType();
+
+  assert(CondVT.isVector() && "Vector select expects a vector selector!");
+
+  // Classify TVal/FVal content
+  bool IsTAllZero = ISD::isBuildVectorAllZeros(TVal.getNode());
+  bool IsTAllOne = ISD::isBuildVectorAllOnes(TVal.getNode());
+  bool IsFAllZero = ISD::isBuildVectorAllZeros(FVal.getNode());
+  bool IsFAllOne = ISD::isBuildVectorAllOnes(FVal.getNode());
+
+  // no vselect(cond, 0/-1, X) or vselect(cond, X, 0/-1), return
+  if (!(IsTAllZero || IsTAllOne || IsFAllZero || IsFAllOne))
----------------
woruyu wrote:

OK, understand, I will modify it.

https://github.com/llvm/llvm-project/pull/145298