lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp

//===-- HexagonSelectionDAGInfo.cpp - Hexagon 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 HexagonSelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//

#include "HexagonTargetMachine.h"
#include "llvm/CodeGen/SelectionDAG.h"
using namespace llvm;

#define DEBUG_TYPE "hexagon-selectiondag-info"

SDValue
HexagonSelectionDAGInfo::
EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc dl, SDValue Chain,
                        SDValue Dst, SDValue Src, SDValue Size, unsigned Align,
                        bool isVolatile, bool AlwaysInline,
                        MachinePointerInfo DstPtrInfo,
                        MachinePointerInfo SrcPtrInfo) const {
  ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
  if (AlwaysInline || (Align & 0x3) != 0 || !ConstantSize)
    return SDValue();

  uint64_t SizeVal = ConstantSize->getZExtValue();
  if (SizeVal < 32 || (SizeVal % 8) != 0)
    return SDValue();

  // Special case aligned memcpys with size >= 32 bytes and a multiple of 8.
  //
  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);

  const char *SpecialMemcpyName =
      "__hexagon_memcpy_likely_aligned_min32bytes_mult8bytes";

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

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