[X86][NFC] Rename 'Src' to 'Val'.

[courbet]

Summary

'Src' looks like it was borrowed from memcpy, 'Val' makes more sense for
memset and is consistent with naming within the function.

(pulled out from D32481)

[zvi]

LGTM, thanks

lib/Target/X86/X86SelectionDAGInfo.cpp

bool X86SelectionDAGInfo::isBaseRegConflictPossible(
   unsigned BaseReg = TRI->getBaseRegister();
   for (unsigned R : ClobberSet)
     if (BaseReg == R)
       return true;
   return false;
 }
 
 SDValue X86SelectionDAGInfo::EmitTargetCodeForMemset(
-    SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
+    SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Val,
     SDValue Size, unsigned Align, bool isVolatile,
     MachinePointerInfo DstPtrInfo) const {
   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
   const X86Subtarget &Subtarget =
       DAG.getMachineFunction().getSubtarget<X86Subtarget>();
 
 #ifndef NDEBUG
   // If the base register might conflict with our physical registers, bail out.
   const MCPhysReg ClobberSet[] = {X86::RCX, X86::RAX, X86::RDI,
                                   X86::ECX, X86::EAX, X86::EDI};
   assert(!isBaseRegConflictPossible(DAG, ClobberSet));
 #endif
 
   // If to a segment-relative address space, use the default lowering.
   if (DstPtrInfo.getAddrSpace() >= 256)
     return SDValue();
 
   // If not DWORD aligned or size is more than the threshold, call the library.
   // The libc version is likely to be faster for these cases. It can use the
   // address value and run time information about the CPU.
   if ((Align & 3) != 0 || !ConstantSize ||
       ConstantSize->getZExtValue() > Subtarget.getMaxInlineSizeThreshold()) {
     // Check to see if there is a specialized entry-point for memory zeroing.
-    ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
+    ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);
 
-    if (const char *bzeroEntry = V &&
-        V->isNullValue() ? Subtarget.getBZeroEntry() : nullptr) {
+    if (const char *bzeroEntry = ValC &&
+        ValC->isNullValue() ? Subtarget.getBZeroEntry() : nullptr) {
       const TargetLowering &TLI = DAG.getTargetLoweringInfo();
       EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
       Type *IntPtrTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
       TargetLowering::ArgListTy Args;
       TargetLowering::ArgListEntry Entry;
       Entry.Node = Dst;
       Entry.Ty = IntPtrTy;
       Args.push_back(Entry);
if ((Align & 3) != 0 || !ConstantSize ||
     // Otherwise have the target-independent code call memset.
     return SDValue();
   }
 
   uint64_t SizeVal = ConstantSize->getZExtValue();
   SDValue InFlag;
   EVT AVT;
   SDValue Count;
-  ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Src);
+  ConstantSDNode *ValC = dyn_cast<ConstantSDNode>(Val);
   unsigned BytesLeft = 0;
   if (ValC) {
     unsigned ValReg;
     uint64_t Val = ValC->getZExtValue() & 255;
 
     // If the value is a constant, then we can potentially use larger sets.
     switch (Align & 3) {
     case 2:   // WORD aligned
if (ValC) {
     }
 
     Chain = DAG.getCopyToReg(Chain, dl, ValReg, DAG.getConstant(Val, dl, AVT),
                              InFlag);
     InFlag = Chain.getValue(1);
   } else {
     AVT = MVT::i8;
     Count  = DAG.getIntPtrConstant(SizeVal, dl);
-    Chain  = DAG.getCopyToReg(Chain, dl, X86::AL, Src, InFlag);
+    Chain  = DAG.getCopyToReg(Chain, dl, X86::AL, Val, InFlag);
     InFlag = Chain.getValue(1);
   }
 
   Chain = DAG.getCopyToReg(Chain, dl, Subtarget.is64Bit() ? X86::RCX : X86::ECX,
                            Count, InFlag);
   InFlag = Chain.getValue(1);
   Chain = DAG.getCopyToReg(Chain, dl, Subtarget.is64Bit() ? X86::RDI : X86::EDI,
                            Dst, InFlag);
   InFlag = Chain.getValue(1);
 
   SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
   SDValue Ops[] = { Chain, DAG.getValueType(AVT), InFlag };
   Chain = DAG.getNode(X86ISD::REP_STOS, dl, Tys, Ops);
 
   if (BytesLeft) {
     // Handle the last 1 - 7 bytes.
     unsigned Offset = SizeVal - BytesLeft;
     EVT AddrVT = Dst.getValueType();
     EVT SizeVT = Size.getValueType();
 
     Chain = DAG.getMemset(Chain, dl,
                           DAG.getNode(ISD::ADD, dl, AddrVT, Dst,
                                       DAG.getConstant(Offset, dl, AddrVT)),
-                          Src,
+                          Val,
                           DAG.getConstant(BytesLeft, dl, SizeVT),
                           Align, isVolatile, false,
                           DstPtrInfo.getWithOffset(Offset));
   }
 
   // TODO: Use a Tokenfactor, as in memcpy, instead of a single chain.
   return Chain;
 }