XCoreSelectionDAGInfo.cpp

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//===-- XCoreSelectionDAGInfo.cpp - XCore SelectionDAG Info ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the XCoreSelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//
 
#include "XCoreSelectionDAGInfo.h"
#include "XCoreTargetMachine.h"
 
#define GET_SDNODE_DESC
#include "XCoreGenSDNodeInfo.inc"
 
using namespace llvm;
 
#define DEBUG_TYPE "xcore-selectiondag-info"
 
XCoreSelectionDAGInfo::XCoreSelectionDAGInfo()
    : SelectionDAGGenTargetInfo(XCoreGenSDNodeInfo) {}
 
SDValue XCoreSelectionDAGInfo::EmitTargetCodeForMemcpy(
    SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
    SDValue Size, Align Alignment, bool isVolatile, bool AlwaysInline,
    MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  unsigned SizeBitWidth = Size.getValueSizeInBits();
  // Call __memcpy_4 if the src, dst and size are all 4 byte aligned.
  if (!AlwaysInline && Alignment >= Align(4) &&
      DAG.MaskedValueIsZero(Size, APInt(SizeBitWidth, 3))) {
    const TargetLowering &TLI = *DAG.getSubtarget().getTargetLowering();
    TargetLowering::ArgListTy Args;
    Type *ArgTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
    Args.emplace_back(Dst, ArgTy);
    Args.emplace_back(Src, ArgTy);
    Args.emplace_back(Size, ArgTy);
 
    const char *MemcpyAlign4Name = TLI.getLibcallName(RTLIB::MEMCPY_ALIGN_4);
    CallingConv::ID CC = TLI.getLibcallCallingConv(RTLIB::MEMCPY_ALIGN_4);
 
    TargetLowering::CallLoweringInfo CLI(DAG);
    CLI.setDebugLoc(dl)
        .setChain(Chain)
        .setLibCallee(
            CC, Type::getVoidTy(*DAG.getContext()),
            DAG.getExternalSymbol(MemcpyAlign4Name,
                                  TLI.getPointerTy(DAG.getDataLayout())),
            std::move(Args))
        .setDiscardResult();
 
    std::pair<SDValue,SDValue> CallResult = TLI.LowerCallTo(CLI);
    return CallResult.second;
  }
 
  // Otherwise have the target-independent code call memcpy.
  return SDValue();
}