lib/Target/XCore/XCoreSelectionDAGInfo.cpp

//===-- XCoreSelectionDAGInfo.cpp - XCore SelectionDAG Info ---------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the XCoreSelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//

#include "XCoreTargetMachine.h"
using namespace llvm;

#define DEBUG_TYPE "xcore-selectiondag-info"

SDValue XCoreSelectionDAGInfo::
EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc dl, SDValue Chain,
                        SDValue Dst, SDValue Src, SDValue Size, unsigned Align,
                        bool isVolatile, bool AlwaysInline,
                        MachinePointerInfo DstPtrInfo,
                        MachinePointerInfo SrcPtrInfo) const
{
  unsigned SizeBitWidth = Size.getValueType().getSizeInBits();
  // Call __memcpy_4 if the src, dst and size are all 4 byte aligned.
  if (!AlwaysInline && (Align & 3) == 0 &&
      DAG.MaskedValueIsZero(Size, APInt(SizeBitWidth, 3))) {
    const TargetLowering &TLI = *DAG.getSubtarget().getTargetLowering();
    TargetLowering::ArgListTy Args;
    TargetLowering::ArgListEntry Entry;
    Entry.Ty = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
    Entry.Node = Dst; Args.push_back(Entry);
    Entry.Node = Src; Args.push_back(Entry);
    Entry.Node = Size; Args.push_back(Entry);

    TargetLowering::CallLoweringInfo CLI(DAG);
    CLI.setDebugLoc(dl)
        .setChain(Chain)
        .setCallee(TLI.getLibcallCallingConv(RTLIB::MEMCPY),
                   Type::getVoidTy(*DAG.getContext()),
                   DAG.getExternalSymbol("__memcpy_4",
                                         TLI.getPointerTy(DAG.getDataLayout())),
                   std::move(Args), 0)
        .setDiscardResult();

    std::pair<SDValue,SDValue> CallResult = TLI.LowerCallTo(CLI);
    return CallResult.second;
  }

  // Otherwise have the target-independent code call memcpy.
  return SDValue();
}