lib/Target/Hexagon/HexagonSelectionDAGInfo.cpp

   1 //===-- HexagonSelectionDAGInfo.cpp - Hexagon 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 HexagonSelectionDAGInfo class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "HexagonTargetMachine.h"
  14 #include "llvm/CodeGen/SelectionDAG.h"
  15 using namespace llvm;
  16
  17 #define DEBUG_TYPE "hexagon-selectiondag-info"
  18
  19 SDValue HexagonSelectionDAGInfo::EmitTargetCodeForMemcpy(
  20     SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
  21     SDValue Size, unsigned Align, bool isVolatile, bool AlwaysInline,
  22     MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  23   ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
  24   if (AlwaysInline || (Align & 0x3) != 0 || !ConstantSize)
  25     return SDValue();
  26
  27   uint64_t SizeVal = ConstantSize->getZExtValue();
  28   if (SizeVal < 32 || (SizeVal % 8) != 0)
  29     return SDValue();
  30
  31   // Special case aligned memcpys with size >= 32 bytes and a multiple of 8.
  32   //
  33   const TargetLowering &TLI = *DAG.getSubtarget().getTargetLowering();
  34   TargetLowering::ArgListTy Args;
  35   TargetLowering::ArgListEntry Entry;
  36   Entry.Ty = DAG.getDataLayout().getIntPtrType(*DAG.getContext());
  37   Entry.Node = Dst;
  38   Args.push_back(Entry);
  39   Entry.Node = Src;
  40   Args.push_back(Entry);
  41   Entry.Node = Size;
  42   Args.push_back(Entry);
  43
  44   const char *SpecialMemcpyName =
  45       "__hexagon_memcpy_likely_aligned_min32bytes_mult8bytes";
  46   const MachineFunction &MF = DAG.getMachineFunction();
  47   bool LongCalls = MF.getSubtarget<HexagonSubtarget>().useLongCalls();
  48   unsigned Flags = LongCalls ? HexagonII::HMOTF_ConstExtended : 0;
  49
  50   TargetLowering::CallLoweringInfo CLI(DAG);
  51   CLI.setDebugLoc(dl)
  52       .setChain(Chain)
  53       .setLibCallee(
  54           TLI.getLibcallCallingConv(RTLIB::MEMCPY),
  55           Type::getVoidTy(*DAG.getContext()),
  56           DAG.getTargetExternalSymbol(
  57               SpecialMemcpyName, TLI.getPointerTy(DAG.getDataLayout()), Flags),
  58           std::move(Args))
  59       .setDiscardResult();
  60
  61   std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
  62   return CallResult.second;
  63 }