lib/Target/AArch64/AArch64SelectionDAGInfo.cpp

   1 //===-- AArch64SelectionDAGInfo.cpp - AArch64 SelectionDAG Info -----------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the AArch64SelectionDAGInfo class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "AArch64TargetMachine.h"
  14 using namespace llvm;
  15
  16 #define DEBUG_TYPE "aarch64-selectiondag-info"
  17
  18 SDValue AArch64SelectionDAGInfo::EmitTargetCodeForMemset(
  19     SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
  20     SDValue Size, unsigned Align, bool isVolatile,
  21     MachinePointerInfo DstPtrInfo) const {
  22   // Check to see if there is a specialized entry-point for memory zeroing.
  23   ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
  24   ConstantSDNode *SizeValue = dyn_cast<ConstantSDNode>(Size);
  25   const AArch64Subtarget &STI =
  26       DAG.getMachineFunction().getSubtarget<AArch64Subtarget>();
  27   const char *bzeroName = (V && V->isNullValue())
  28       ? DAG.getTargetLoweringInfo().getLibcallName(RTLIB::BZERO) : nullptr;
  29   // For small size (< 256), it is not beneficial to use bzero
  30   // instead of memset.
  31   if (bzeroName && (!SizeValue || SizeValue->getZExtValue() > 256)) {
  32     const AArch64TargetLowering &TLI = *STI.getTargetLowering();
  33
  34     EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
  35     Type *IntPtrTy = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
  36     TargetLowering::ArgListTy Args;
  37     TargetLowering::ArgListEntry Entry;
  38     Entry.Node = Dst;
  39     Entry.Ty = IntPtrTy;
  40     Args.push_back(Entry);
  41     Entry.Node = Size;
  42     Args.push_back(Entry);
  43     TargetLowering::CallLoweringInfo CLI(DAG);
  44     CLI.setDebugLoc(dl)
  45         .setChain(Chain)
  46         .setLibCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
  47                       DAG.getExternalSymbol(bzeroName, IntPtr),
  48                       std::move(Args))
  49         .setDiscardResult();
  50     std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
  51     return CallResult.second;
  52   }
  53   return SDValue();
  54 }
  55 bool AArch64SelectionDAGInfo::generateFMAsInMachineCombiner(
  56     CodeGenOpt::Level OptLevel) const {
  57   return OptLevel >= CodeGenOpt::Aggressive;
  58 }