fix: modify review for code details

Author: woruyu

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -1937,8 +1937,14 @@ LLVM_ABI bool isOneOrOneSplat(SDValue V, bool AllowUndefs = false);
 /// Does not permit build vector implicit truncation.
 LLVM_ABI bool isAllOnesOrAllOnesSplat(SDValue V, bool AllowUndefs = false);
 
+/// Return true if the value is a constant 1 integer or a splatted vector of a
+/// constant 1 integer (with no undefs).
+/// Does not permit build vector implicit truncation.
 LLVM_ABI bool isOnesOrOnesSplat(SDValue N, bool AllowUndefs = false);
 
+/// Return true if the value is a constant 0 integer or a splatted vector of a
+/// constant 0 integer (with no undefs).
+/// Does not permit build vector implicit truncation.
 LLVM_ABI bool isZeroOrZeroSplat(SDValue N, bool AllowUndefs = false);
 
 /// Return true if \p V is either a integer or FP constant.

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -4281,7 +4281,8 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
     return V;
 
   // (A - B) - 1  ->  add (xor B, -1), A
-  if (sd_match(N, m_Sub(m_OneUse(m_Sub(m_Value(A), m_Value(B))), m_One(true))))
+  if (sd_match(N, m_Sub(m_OneUse(m_Sub(m_Value(A), m_Value(B))),
+                        m_One(/*AllowUndefs=*/true))))
     return DAG.getNode(ISD::ADD, DL, VT, A, DAG.getNOT(DL, B, VT));
 
   // Look for:

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -12570,9 +12570,9 @@ bool llvm::isAllOnesOrAllOnesSplat(SDValue N, bool AllowUndefs) {
 }
 
 bool llvm::isOnesOrOnesSplat(SDValue N, bool AllowUndefs) {
-  N = peekThroughBitcasts(N);
   ConstantSDNode *C = isConstOrConstSplat(N, AllowUndefs);
-  return C && C->getAPIntValue() == 1;
+  return C && APInt::isSameValue(C->getAPIntValue(),
+                                 APInt(C->getAPIntValue().getBitWidth(), 1));
 }
 
 bool llvm::isZeroOrZeroSplat(SDValue N, bool AllowUndefs) {

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -57925,20 +57925,22 @@ static SDValue combineAdd(SDNode *N, SelectionDAG &DAG,
     }
   }
 
-  SDValue X, Y;
-
   // add(psadbw(X,0),psadbw(Y,0)) -> psadbw(add(X,Y),0)
   // iff X and Y won't overflow.
-  if (sd_match(Op0, m_c_BinOp(X86ISD::PSADBW, m_Value(X), m_Zero())) &&
-      sd_match(Op1, m_c_BinOp(X86ISD::PSADBW, m_Value(Y), m_Zero())) &&
-      DAG.willNotOverflowAdd(/*IsSigned=*/false, X, Y)) {
-    MVT OpVT = X.getSimpleValueType();
-    SDValue Sum = DAG.getNode(ISD::ADD, DL, OpVT, X, Y);
-    return DAG.getNode(X86ISD::PSADBW, DL, VT, Sum,
-                       getZeroVector(OpVT, Subtarget, DAG, DL));
+  if (Op0.getOpcode() == X86ISD::PSADBW && Op1.getOpcode() == X86ISD::PSADBW &&
+      ISD::isBuildVectorAllZeros(Op0.getOperand(1).getNode()) &&
+      ISD::isBuildVectorAllZeros(Op1.getOperand(1).getNode())) {
+    if (DAG.willNotOverflowAdd(false, Op0.getOperand(0), Op1.getOperand(0))) {
+      MVT OpVT = Op0.getOperand(1).getSimpleValueType();
+      SDValue Sum =
+          DAG.getNode(ISD::ADD, DL, OpVT, Op0.getOperand(0), Op1.getOperand(0));
+      return DAG.getNode(X86ISD::PSADBW, DL, VT, Sum,
+                         getZeroVector(OpVT, Subtarget, DAG, DL));
+    }
   }
 
   if (VT.isVector()) {
+    SDValue X, Y;
     EVT BoolVT = EVT::getVectorVT(*DAG.getContext(), MVT::i1,
                                   VT.getVectorElementCount());
 

llvm/unittests/CodeGen/SelectionDAGPatternMatchTest.cpp

@@ -867,7 +867,7 @@ TEST_F(SelectionDAGPatternMatchTest, MatchZeroOneAllOnes) {
     SDValue SplatVal = DAG->getConstant(1, DL, MVT::i32);
     SDValue VecSplat = DAG->getSplatBuildVector(VecVT, DL, SplatVal);
     SDValue Bitcasted = DAG->getNode(ISD::BITCAST, DL, VecF32, VecSplat);
-    EXPECT_TRUE(sd_match(Bitcasted, DAG.get(), m_One()));
+    EXPECT_FALSE(sd_match(Bitcasted, DAG.get(), m_One()));
   }
 
   // m_AllOnes: splat vector of -1 → bitcast
@@ -887,9 +887,8 @@ TEST_F(SelectionDAGPatternMatchTest, MatchZeroOneAllOnes) {
     SmallVector<SDValue, 4> Ops(4, Zero);
     Ops[2] = Undef;
     SDValue Vec = DAG->getBuildVector(VecVT, DL, Ops);
-    SDValue Bitcasted = DAG->getNode(ISD::BITCAST, DL, VecF32, Vec);
-    EXPECT_FALSE(sd_match(Bitcasted, DAG.get(), m_Zero()));
-    EXPECT_TRUE(sd_match(Bitcasted, DAG.get(), m_Zero(true)));
+    EXPECT_FALSE(sd_match(Vec, DAG.get(), m_Zero()));
+    EXPECT_TRUE(sd_match(Vec, DAG.get(), m_Zero(true)));
   }
 
   {
@@ -898,9 +897,8 @@ TEST_F(SelectionDAGPatternMatchTest, MatchZeroOneAllOnes) {
     SmallVector<SDValue, 4> Ops(4, One);
     Ops[1] = Undef;
     SDValue Vec = DAG->getBuildVector(VecVT, DL, Ops);
-    SDValue Bitcasted = DAG->getNode(ISD::BITCAST, DL, VecF32, Vec);
-    EXPECT_FALSE(sd_match(Bitcasted, DAG.get(), m_One()));
-    EXPECT_TRUE(sd_match(Bitcasted, DAG.get(), m_One(true)));
+    EXPECT_FALSE(sd_match(Vec, DAG.get(), m_One()));
+    EXPECT_TRUE(sd_match(Vec, DAG.get(), m_One(true)));
   }
 
   {
@@ -909,8 +907,7 @@ TEST_F(SelectionDAGPatternMatchTest, MatchZeroOneAllOnes) {
     SmallVector<SDValue, 4> Ops(4, AllOnes);
     Ops[0] = Undef;
     SDValue Vec = DAG->getBuildVector(VecVT, DL, Ops);
-    SDValue Bitcasted = DAG->getNode(ISD::BITCAST, DL, VecF32, Vec);
-    EXPECT_FALSE(sd_match(Bitcasted, DAG.get(), m_AllOnes()));
-    EXPECT_TRUE(sd_match(Bitcasted, DAG.get(), m_AllOnes(true)));
+    EXPECT_FALSE(sd_match(Vec, DAG.get(), m_AllOnes()));
+    EXPECT_TRUE(sd_match(Vec, DAG.get(), m_AllOnes(true)));
   }
 }