[AMDGPU] Use isNullConstant and isOneConstant (NFC)

Author: kazutakahirata

llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp

@@ -81,10 +81,9 @@ static bool isExtractHiElt(SDValue In, SDValue &Out) {
 // same register.
 static SDValue stripExtractLoElt(SDValue In) {
   if (In.getOpcode() == ISD::EXTRACT_VECTOR_ELT) {
-    if (ConstantSDNode *Idx = dyn_cast<ConstantSDNode>(In.getOperand(1))) {
-      if (Idx->isZero() && In.getValueSizeInBits() <= 32)
-        return In.getOperand(0);
-    }
+    SDValue Idx = In.getOperand(1);
+    if (isNullConstant(Idx) && In.getValueSizeInBits() <= 32)
+      return In.getOperand(0);
   }
 
   if (In.getOpcode() == ISD::TRUNCATE) {

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp

@@ -4046,8 +4046,7 @@ static SDValue getAddOneOp(const SDNode *V) {
   if (V->getOpcode() != ISD::ADD)
     return SDValue();
 
-  auto *C = dyn_cast<ConstantSDNode>(V->getOperand(1));
-  return C && C->isOne() ? V->getOperand(0) : SDValue();
+  return isOneConstant(V->getOperand(1)) ? V->getOperand(0) : SDValue();
 }
 
 SDValue AMDGPUTargetLowering::performMulCombine(SDNode *N,
@@ -4277,8 +4276,7 @@ SDValue AMDGPUTargetLowering::getFFBX_U32(SelectionDAG &DAG,
 SDValue AMDGPUTargetLowering::performCtlz_CttzCombine(const SDLoc &SL, SDValue Cond,
                                                  SDValue LHS, SDValue RHS,
                                                  DAGCombinerInfo &DCI) const {
-  ConstantSDNode *CmpRhs = dyn_cast<ConstantSDNode>(Cond.getOperand(1));
-  if (!CmpRhs || !CmpRhs->isZero())
+  if (!isNullConstant(Cond.getOperand(1)))
     return SDValue();
 
   SelectionDAG &DAG = DCI.DAG;

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -8643,8 +8643,7 @@ SDValue SITargetLowering::LowerINTRINSIC_VOID(SDValue Op,
         IntrinsicID == Intrinsic::amdgcn_struct_ptr_buffer_load_lds;
     unsigned OpOffset = HasVIndex ? 1 : 0;
     SDValue VOffset = Op.getOperand(5 + OpOffset);
-    auto CVOffset = dyn_cast<ConstantSDNode>(VOffset);
-    bool HasVOffset = !CVOffset || !CVOffset->isZero();
+    bool HasVOffset = !isNullConstant(VOffset);
     unsigned Size = Op->getConstantOperandVal(4);
 
     switch (Size) {
@@ -11101,10 +11100,8 @@ SDValue SITargetLowering::performClassCombine(SDNode *N,
   SDValue Mask = N->getOperand(1);
 
   // fp_class x, 0 -> false
-  if (const ConstantSDNode *CMask = dyn_cast<ConstantSDNode>(Mask)) {
-    if (CMask->isZero())
-      return DAG.getConstant(0, SDLoc(N), MVT::i1);
-  }
+  if (isNullConstant(Mask))
+    return DAG.getConstant(0, SDLoc(N), MVT::i1);
 
   if (N->getOperand(0).isUndef())
     return DAG.getUNDEF(MVT::i1);
@@ -12378,8 +12375,7 @@ SDValue SITargetLowering::performSubCombine(SDNode *N,
 
   if (LHS.getOpcode() == ISD::USUBO_CARRY) {
     // sub (usubo_carry x, 0, cc), y => usubo_carry x, y, cc
-    auto C = dyn_cast<ConstantSDNode>(LHS.getOperand(1));
-    if (!C || !C->isZero())
+    if (!isNullConstant(LHS.getOperand(1)))
       return SDValue();
     SDValue Args[] = { LHS.getOperand(0), RHS, LHS.getOperand(2) };
     return DAG.getNode(ISD::USUBO_CARRY, SDLoc(N), LHS->getVTList(), Args);