1 files changed, 20 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 980db1012be..7caaa1fb58c 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -34109,6 +34109,23 @@ static SDValue lowerX86FPLogicOp(SDNode *N, SelectionDAG &DAG,
   return SDValue();
 }
 
+
+/// Fold a xor(setcc cond, val), 1 --> setcc (inverted(cond), val)
+static SDValue foldXor1SetCC(SDNode *N, SelectionDAG &DAG) {
+  if (N->getOpcode() != ISD::XOR)
+    return SDValue();
+
+  SDValue LHS = N->getOperand(0);
+  auto *RHSC = dyn_cast<ConstantSDNode>(N->getOperand(1));
+  if (!RHSC || RHSC->getZExtValue() != 1 || LHS->getOpcode() != X86ISD::SETCC)
+    return SDValue();
+
+  X86::CondCode NewCC = X86::GetOppositeBranchCondition(
+      X86::CondCode(LHS->getConstantOperandVal(0)));
+  SDLoc DL(N);
+  return getSETCC(NewCC, LHS->getOperand(1), DL, DAG);
+}
+
 static SDValue combineXor(SDNode *N, SelectionDAG &DAG,
                           TargetLowering::DAGCombinerInfo &DCI,
                           const X86Subtarget &Subtarget) {
@@ -34118,6 +34135,9 @@ static SDValue combineXor(SDNode *N, SelectionDAG &DAG,
   if (DCI.isBeforeLegalizeOps())
     return SDValue();
 
+  if (SDValue SetCC = foldXor1SetCC(N, DAG))
+    return SetCC;
+
   if (SDValue RV = foldXorTruncShiftIntoCmp(N, DAG))
     return RV;