[DAG] Add SDPatternMatch::m_BitwiseLogic common matcher for AND/OR/XOR nodes (llvm#138301)

Author: RKSimon

llvm/include/llvm/CodeGen/SDPatternMatch.h

@@ -729,6 +729,11 @@ inline BinaryOpc_match<LHS, RHS, true> m_Xor(const LHS &L, const RHS &R) {
   return BinaryOpc_match<LHS, RHS, true>(ISD::XOR, L, R);
 }
 
+template <typename LHS, typename RHS>
+inline auto m_BitwiseLogic(const LHS &L, const RHS &R) {
+  return m_AnyOf(m_And(L, R), m_Or(L, R), m_Xor(L, R));
+}
+
 template <typename LHS, typename RHS>
 inline BinaryOpc_match<LHS, RHS, true> m_SMin(const LHS &L, const RHS &R) {
   return BinaryOpc_match<LHS, RHS, true>(ISD::SMIN, L, R);

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -10553,29 +10553,20 @@ static SDValue foldBitOrderCrossLogicOp(SDNode *N, SelectionDAG &DAG) {
   SDValue N0 = N->getOperand(0);
   EVT VT = N->getValueType(0);
   SDLoc DL(N);
-  if (ISD::isBitwiseLogicOp(N0.getOpcode()) && N0.hasOneUse()) {
-    SDValue OldLHS = N0.getOperand(0);
-    SDValue OldRHS = N0.getOperand(1);
-
-    // If both operands are bswap/bitreverse, ignore the multiuse
-    // Otherwise need to ensure logic_op and bswap/bitreverse(x) have one use.
-    if (OldLHS.getOpcode() == Opcode && OldRHS.getOpcode() == Opcode) {
-      return DAG.getNode(N0.getOpcode(), DL, VT, OldLHS.getOperand(0),
-                         OldRHS.getOperand(0));
-    }
+  SDValue X, Y;
 
-    if (OldLHS.getOpcode() == Opcode && OldLHS.hasOneUse()) {
-      SDValue NewBitReorder = DAG.getNode(Opcode, DL, VT, OldRHS);
-      return DAG.getNode(N0.getOpcode(), DL, VT, OldLHS.getOperand(0),
-                         NewBitReorder);
-    }
+  // If both operands are bswap/bitreverse, ignore the multiuse
+  if (sd_match(N0, m_OneUse(m_BitwiseLogic(m_UnaryOp(Opcode, m_Value(X)),
+                                           m_UnaryOp(Opcode, m_Value(Y))))))
+    return DAG.getNode(N0.getOpcode(), DL, VT, X, Y);
 
-    if (OldRHS.getOpcode() == Opcode && OldRHS.hasOneUse()) {
-      SDValue NewBitReorder = DAG.getNode(Opcode, DL, VT, OldLHS);
-      return DAG.getNode(N0.getOpcode(), DL, VT, NewBitReorder,
-                         OldRHS.getOperand(0));
-    }
+  // Otherwise need to ensure logic_op and bswap/bitreverse(x) have one use.
+  if (sd_match(N0, m_OneUse(m_BitwiseLogic(
+                       m_OneUse(m_UnaryOp(Opcode, m_Value(X))), m_Value(Y))))) {
+    SDValue NewBitReorder = DAG.getNode(Opcode, DL, VT, Y);
+    return DAG.getNode(N0.getOpcode(), DL, VT, X, NewBitReorder);
   }
+
   return SDValue();
 }
 

llvm/test/CodeGen/ARM/combine-bswap.ll

@@ -23,7 +23,7 @@ define i64 @bs_or_rhs_bs64(i64 %a, i64 %b) #0 {
 ; CHECK-NEXT:    rev r1, r1
 ; CHECK-NEXT:    rev r0, r0
 ; CHECK-NEXT:    orrs r2, r1
-; CHECK-NEXT:    orr.w r1, r0, r3
+; CHECK-NEXT:    orr.w r1, r3, r0
 ; CHECK-NEXT:    mov r0, r2
 ; CHECK-NEXT:    bx lr
   %1 = tail call i64 @llvm.bswap.i64(i64 %b)

llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp

@@ -302,13 +302,18 @@ TEST_F(SelectionDAGPatternMatchTest, matchBinaryOp) {
   EXPECT_TRUE(
       sd_match(SFAdd, m_ChainedBinOp(ISD::STRICT_FADD, m_SpecificVT(Float32VT),
                                      m_SpecificVT(Float32VT))));
+  EXPECT_FALSE(sd_match(Add, m_BitwiseLogic(m_Value(), m_Value())));
+  EXPECT_FALSE(sd_match(Sub, m_BitwiseLogic(m_Value(), m_Value())));
 
   EXPECT_TRUE(sd_match(And, m_c_BinOp(ISD::AND, m_Value(), m_Value())));
   EXPECT_TRUE(sd_match(And, m_And(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(And, m_BitwiseLogic(m_Value(), m_Value())));
   EXPECT_TRUE(sd_match(Xor, m_c_BinOp(ISD::XOR, m_Value(), m_Value())));
   EXPECT_TRUE(sd_match(Xor, m_Xor(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(Xor, m_BitwiseLogic(m_Value(), m_Value())));
   EXPECT_TRUE(sd_match(Or, m_c_BinOp(ISD::OR, m_Value(), m_Value())));
   EXPECT_TRUE(sd_match(Or, m_Or(m_Value(), m_Value())));
+  EXPECT_TRUE(sd_match(Or, m_BitwiseLogic(m_Value(), m_Value())));
   EXPECT_FALSE(sd_match(Or, m_DisjointOr(m_Value(), m_Value())));
 
   EXPECT_TRUE(sd_match(DisOr, m_Or(m_Value(), m_Value())));