[CodeGen] Use isAllOnesConstant and isNullConstant (NFC)

Author: kazutakahirata

llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

@@ -5149,16 +5149,11 @@ void DAGTypeLegalizer::IntegerExpandSetCCOperands(SDValue &NewLHS,
   GetExpandedInteger(NewRHS, RHSLo, RHSHi);
 
   if (CCCode == ISD::SETEQ || CCCode == ISD::SETNE) {
-    if (RHSLo == RHSHi) {
-      if (ConstantSDNode *RHSCST = dyn_cast<ConstantSDNode>(RHSLo)) {
-        if (RHSCST->isAllOnes()) {
-          // Equality comparison to -1.
-          NewLHS = DAG.getNode(ISD::AND, dl,
-                               LHSLo.getValueType(), LHSLo, LHSHi);
-          NewRHS = RHSLo;
-          return;
-        }
-      }
+    if (RHSLo == RHSHi && isAllOnesConstant(RHSLo)) {
+      // Equality comparison to -1.
+      NewLHS = DAG.getNode(ISD::AND, dl, LHSLo.getValueType(), LHSLo, LHSHi);
+      NewRHS = RHSLo;
+      return;
     }
 
     NewLHS = DAG.getNode(ISD::XOR, dl, LHSLo.getValueType(), LHSLo, RHSLo);

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -2145,11 +2145,8 @@ SDValue SelectionDAG::getVectorShuffle(EVT VT, const SDLoc &dl, SDValue N1,
       if (Splat && UndefElements.none()) {
         // Splat of <x, x, ..., x>, return <x, x, ..., x>, provided that the
         // number of elements match or the value splatted is a zero constant.
-        if (SameNumElts)
+        if (SameNumElts || isNullConstant(Splat))
           return N1;
-        if (auto *C = dyn_cast<ConstantSDNode>(Splat))
-          if (C->isZero())
-            return N1;
       }
 
       // If the shuffle itself creates a splat, build the vector directly.
@@ -8028,8 +8025,6 @@ SDValue SelectionDAG::getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
   // FIXME: pass in SDLoc
   CLI.setDebugLoc(dl).setChain(Chain);
 
-  ConstantSDNode *ConstantSrc = dyn_cast<ConstantSDNode>(Src);
-  const bool SrcIsZero = ConstantSrc && ConstantSrc->isZero();
   const char *BzeroName = getTargetLoweringInfo().getLibcallName(RTLIB::BZERO);
 
   // Helper function to create an Entry from Node and Type.
@@ -8041,7 +8036,7 @@ SDValue SelectionDAG::getMemset(SDValue Chain, const SDLoc &dl, SDValue Dst,
   };
 
   // If zeroing out and bzero is present, use it.
-  if (SrcIsZero && BzeroName) {
+  if (isNullConstant(Src) && BzeroName) {
     TargetLowering::ArgListTy Args;
     Args.push_back(CreateEntry(Dst, PointerType::getUnqual(Ctx)));
     Args.push_back(CreateEntry(Size, DL.getIntPtrType(Ctx)));

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -3900,8 +3900,7 @@ SDValue TargetLowering::foldSetCCWithAnd(EVT VT, SDValue N0, SDValue N1,
 
     // Bail out if the compare operand that we want to turn into a zero is
     // already a zero (otherwise, infinite loop).
-    auto *YConst = dyn_cast<ConstantSDNode>(Y);
-    if (YConst && YConst->isZero())
+    if (isNullConstant(Y))
       return SDValue();
 
     // Transform this into: ~X & Y == 0.