[DAGCombiner] ISD::AND/OR/XOR - use general SelectionDAG::FoldConstantArithmetic

This handles all the constant splat / opaque testing for us.

Author: RKSimon

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -5165,17 +5165,19 @@ SDValue DAGCombiner::visitAND(SDNode *N) {
   }
 
   // fold (and c1, c2) -> c1&c2
-  ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
   ConstantSDNode *N1C = isConstOrConstSplat(N1);
-  if (N0C && N1C && !N1C->isOpaque())
-    return DAG.FoldConstantArithmetic(ISD::AND, SDLoc(N), VT, N0C, N1C);
+  if (SDValue C = DAG.FoldConstantArithmetic(ISD::AND, SDLoc(N), VT, {N0, N1}))
+    return C;
+
   // canonicalize constant to RHS
   if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
       !DAG.isConstantIntBuildVectorOrConstantInt(N1))
     return DAG.getNode(ISD::AND, SDLoc(N), VT, N1, N0);
+
   // fold (and x, -1) -> x
   if (isAllOnesConstant(N1))
     return N0;
+
   // if (and x, c) is known to be zero, return 0
   unsigned BitWidth = VT.getScalarSizeInBits();
   if (N1C && DAG.MaskedValueIsZero(SDValue(N, 0),
@@ -5866,17 +5868,19 @@ SDValue DAGCombiner::visitOR(SDNode *N) {
   }
 
   // fold (or c1, c2) -> c1|c2
-  ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
   ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1);
-  if (N0C && N1C && !N1C->isOpaque())
-    return DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N), VT, N0C, N1C);
+  if (SDValue C = DAG.FoldConstantArithmetic(ISD::OR, SDLoc(N), VT, {N0, N1}))
+    return C;
+
   // canonicalize constant to RHS
   if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
      !DAG.isConstantIntBuildVectorOrConstantInt(N1))
     return DAG.getNode(ISD::OR, SDLoc(N), VT, N1, N0);
+
   // fold (or x, 0) -> x
   if (isNullConstant(N1))
     return N0;
+
   // fold (or x, -1) -> -1
   if (isAllOnesConstant(N1))
     return N1;
@@ -7021,20 +7025,22 @@ SDValue DAGCombiner::visitXOR(SDNode *N) {
   SDLoc DL(N);
   if (N0.isUndef() && N1.isUndef())
     return DAG.getConstant(0, DL, VT);
+
   // fold (xor x, undef) -> undef
   if (N0.isUndef())
     return N0;
   if (N1.isUndef())
     return N1;
+
   // fold (xor c1, c2) -> c1^c2
-  ConstantSDNode *N0C = getAsNonOpaqueConstant(N0);
-  ConstantSDNode *N1C = getAsNonOpaqueConstant(N1);
-  if (N0C && N1C)
-    return DAG.FoldConstantArithmetic(ISD::XOR, DL, VT, N0C, N1C);
+  if (SDValue C = DAG.FoldConstantArithmetic(ISD::XOR, DL, VT, {N0, N1}))
+    return C;
+
   // canonicalize constant to RHS
   if (DAG.isConstantIntBuildVectorOrConstantInt(N0) &&
      !DAG.isConstantIntBuildVectorOrConstantInt(N1))
     return DAG.getNode(ISD::XOR, DL, VT, N1, N0);
+
   // fold (xor x, 0) -> x
   if (isNullConstant(N1))
     return N0;