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 
19 AArch64SelectionDAGInfo::AArch64SelectionDAGInfo(const DataLayout *DL)
20     : TargetSelectionDAGInfo(DL) {}
21 
22 AArch64SelectionDAGInfo::~AArch64SelectionDAGInfo() {}
23 
24 SDValue AArch64SelectionDAGInfo::EmitTargetCodeForMemset(
25     SelectionDAG &DAG, SDLoc dl, SDValue Chain, SDValue Dst, SDValue Src,
26     SDValue Size, unsigned Align, bool isVolatile,
27     MachinePointerInfo DstPtrInfo) const {
28   // Check to see if there is a specialized entry-point for memory zeroing.
29   ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
30   ConstantSDNode *SizeValue = dyn_cast<ConstantSDNode>(Size);
31   const char *bzeroEntry =
32       (V && V->isNullValue())
33           ? DAG.getTarget().getSubtarget<AArch64Subtarget>().getBZeroEntry()
34           : nullptr;
35   // For small size (< 256), it is not beneficial to use bzero
36   // instead of memset.
37   if (bzeroEntry && (!SizeValue || SizeValue->getZExtValue() > 256)) {
38     const AArch64TargetLowering &TLI =
39         *DAG.getTarget().getSubtarget<AArch64Subtarget>().getTargetLowering();
40 
41     EVT IntPtr = TLI.getPointerTy();
42     Type *IntPtrTy = getDataLayout()->getIntPtrType(*DAG.getContext());
43     TargetLowering::ArgListTy Args;
44     TargetLowering::ArgListEntry Entry;
45     Entry.Node = Dst;
46     Entry.Ty = IntPtrTy;
47     Args.push_back(Entry);
48     Entry.Node = Size;
49     Args.push_back(Entry);
50     TargetLowering::CallLoweringInfo CLI(DAG);
51     CLI.setDebugLoc(dl).setChain(Chain)
52       .setCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
53                  DAG.getExternalSymbol(bzeroEntry, IntPtr), std::move(Args), 0)
54       .setDiscardResult();
55     std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
56     return CallResult.second;
57   }
58   return SDValue();
59 }
60