1 //===-- AArch64SelectionDAGInfo.cpp - AArch64 SelectionDAG Info -----------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the AArch64SelectionDAGInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "AArch64TargetMachine.h"
15 using namespace llvm;
16
17 #define DEBUG_TYPE "aarch64-selectiondag-info"
18
EmitTargetCodeForMemset(SelectionDAG & DAG,SDLoc dl,SDValue Chain,SDValue Dst,SDValue Src,SDValue Size,unsigned Align,bool isVolatile,MachinePointerInfo DstPtrInfo) const19 SDValue AArch64SelectionDAGInfo::EmitTargetCodeForMemset(
20 SelectionDAG &DAG, SDLoc dl, SDValue Chain, SDValue Dst, SDValue Src,
21 SDValue Size, unsigned Align, bool isVolatile,
22 MachinePointerInfo DstPtrInfo) const {
23 // Check to see if there is a specialized entry-point for memory zeroing.
24 ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
25 ConstantSDNode *SizeValue = dyn_cast<ConstantSDNode>(Size);
26 const AArch64Subtarget &STI =
27 DAG.getMachineFunction().getSubtarget<AArch64Subtarget>();
28 const char *bzeroEntry =
29 (V && V->isNullValue()) ? STI.getBZeroEntry() : nullptr;
30 // For small size (< 256), it is not beneficial to use bzero
31 // instead of memset.
32 if (bzeroEntry && (!SizeValue || SizeValue->getZExtValue() > 256)) {
33 const AArch64TargetLowering &TLI = *STI.getTargetLowering();
34
35 EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
36 Type *IntPtrTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
37 TargetLowering::ArgListTy Args;
38 TargetLowering::ArgListEntry Entry;
39 Entry.Node = Dst;
40 Entry.Ty = IntPtrTy;
41 Args.push_back(Entry);
42 Entry.Node = Size;
43 Args.push_back(Entry);
44 TargetLowering::CallLoweringInfo CLI(DAG);
45 CLI.setDebugLoc(dl).setChain(Chain)
46 .setCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
47 DAG.getExternalSymbol(bzeroEntry, IntPtr), std::move(Args), 0)
48 .setDiscardResult();
49 std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
50 return CallResult.second;
51 }
52 return SDValue();
53 }
54