1 files changed, 45 insertions, 11 deletions
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 62073ec..4393f6e 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -4721,9 +4721,6 @@ bool X86DAGToDAGISel::tryVPTERNLOG(SDNode *N) {
   if (!(Subtarget->hasVLX() || NVT.is512BitVector()))
     return false;
 
-  SDValue N0 = N->getOperand(0);
-  SDValue N1 = N->getOperand(1);
-
   auto getFoldableLogicOp = [](SDValue Op) {
     // Peek through single use bitcast.
     if (Op.getOpcode() == ISD::BITCAST && Op.hasOneUse())
@@ -4740,13 +4737,47 @@ bool X86DAGToDAGISel::tryVPTERNLOG(SDNode *N) {
     return SDValue();
   };
 
-  SDValue A, FoldableOp;
-  if ((FoldableOp = getFoldableLogicOp(N1))) {
-    A = N0;
-  } else if ((FoldableOp = getFoldableLogicOp(N0))) {
-    A = N1;
-  } else
-    return false;
+  SDValue N0, N1, A, FoldableOp;
+
+  // Identify and (optionally) peel an outer NOT that wraps a pure logic tree
+  auto tryPeelOuterNotWrappingLogic = [&](SDNode *Op) {
+    if (Op->getOpcode() == ISD::XOR && Op->hasOneUse() &&
+        ISD::isBuildVectorAllOnes(Op->getOperand(1).getNode())) {
+      SDValue InnerOp = Op->getOperand(0);
+
+      if (!getFoldableLogicOp(InnerOp))
+        return SDValue();
+
+      N0 = InnerOp.getOperand(0);
+      N1 = InnerOp.getOperand(1);
+      if ((FoldableOp = getFoldableLogicOp(N1))) {
+        A = N0;
+        return InnerOp;
+      }
+      if ((FoldableOp = getFoldableLogicOp(N0))) {
+        A = N1;
+        return InnerOp;
+      }
+    }
+    return SDValue();
+  };
+
+  bool PeeledOuterNot = false;
+  SDNode *OriN = N;
+  if (SDValue InnerOp = tryPeelOuterNotWrappingLogic(N)) {
+    PeeledOuterNot = true;
+    N = InnerOp.getNode();
+  } else {
+    N0 = N->getOperand(0);
+    N1 = N->getOperand(1);
+
+    if ((FoldableOp = getFoldableLogicOp(N1)))
+      A = N0;
+    else if ((FoldableOp = getFoldableLogicOp(N0)))
+      A = N1;
+    else
+      return false;
+  }
 
   SDValue B = FoldableOp.getOperand(0);
   SDValue C = FoldableOp.getOperand(1);
@@ -4798,7 +4829,10 @@ bool X86DAGToDAGISel::tryVPTERNLOG(SDNode *N) {
   case ISD::XOR: Imm ^= TernlogMagicA; break;
   }
 
-  return matchVPTERNLOG(N, ParentA, ParentB, ParentC, A, B, C, Imm);
+  if (PeeledOuterNot)
+    Imm = ~Imm;
+
+  return matchVPTERNLOG(OriN, ParentA, ParentB, ParentC, A, B, C, Imm);
 }
 
 /// If the high bits of an 'and' operand are known zero, try setting the