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llvm-mirror/lib/Target/XCore/XCoreSelectionDAGInfo.cpp
Richard Osborne 5ac74685fd [XCore] Target optimized library function __memcpy_4()
Summary:
If the src, dst and size of a memcpy are known to be 4 byte aligned we
can call __memcpy_4() instead of memcpy().

Reviewers: robertlytton

Reviewed By: robertlytton

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2871

llvm-svn: 202395
2014-02-27 13:39:07 +00:00

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2.2 KiB
C++

//===-- 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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "xcore-selectiondag-info"
#include "XCoreTargetMachine.h"
using namespace llvm;
XCoreSelectionDAGInfo::XCoreSelectionDAGInfo(const XCoreTargetMachine &TM)
: TargetSelectionDAGInfo(TM) {
}
XCoreSelectionDAGInfo::~XCoreSelectionDAGInfo() {
}
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.getTarget().getTargetLowering();
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Entry.Ty = TLI.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(Chain, Type::getVoidTy(*DAG.getContext()), false, false, false, false,
0, TLI.getLibcallCallingConv(RTLIB::MEMCPY), /*isTailCall=*/false,
/*doesNotRet=*/false, /*isReturnValueUsed=*/false,
DAG.getExternalSymbol("__memcpy_4", TLI.getPointerTy()), Args, DAG, dl);
std::pair<SDValue,SDValue> CallResult =
TLI.LowerCallTo(CLI);
return CallResult.second;
}
// Otherwise have the target-independent code call memcpy.
return SDValue();
}