AArch64SelectionDAGInfo.cpp
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//===-- AArch64SelectionDAGInfo.cpp - AArch64 SelectionDAG Info -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the AArch64SelectionDAGInfo class.
//
//===----------------------------------------------------------------------===//
#include "AArch64TargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "aarch64-selectiondag-info"
SDValue AArch64SelectionDAGInfo::EmitTargetCodeForMemset(
SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Dst, SDValue Src,
SDValue Size, Align Alignment, bool isVolatile,
MachinePointerInfo DstPtrInfo) const {
// Check to see if there is a specialized entry-point for memory zeroing.
ConstantSDNode *V = dyn_cast<ConstantSDNode>(Src);
ConstantSDNode *SizeValue = dyn_cast<ConstantSDNode>(Size);
const AArch64Subtarget &STI =
DAG.getMachineFunction().getSubtarget<AArch64Subtarget>();
const char *bzeroName = (V && V->isNullValue())
? DAG.getTargetLoweringInfo().getLibcallName(RTLIB::BZERO) : nullptr;
// For small size (< 256), it is not beneficial to use bzero
// instead of memset.
if (bzeroName && (!SizeValue || SizeValue->getZExtValue() > 256)) {
const AArch64TargetLowering &TLI = *STI.getTargetLowering();
EVT IntPtr = TLI.getPointerTy(DAG.getDataLayout());
Type *IntPtrTy = Type::getInt8PtrTy(*DAG.getContext());
TargetLowering::ArgListTy Args;
TargetLowering::ArgListEntry Entry;
Entry.Node = Dst;
Entry.Ty = IntPtrTy;
Args.push_back(Entry);
Entry.Node = Size;
Args.push_back(Entry);
TargetLowering::CallLoweringInfo CLI(DAG);
CLI.setDebugLoc(dl)
.setChain(Chain)
.setLibCallee(CallingConv::C, Type::getVoidTy(*DAG.getContext()),
DAG.getExternalSymbol(bzeroName, IntPtr),
std::move(Args))
.setDiscardResult();
std::pair<SDValue, SDValue> CallResult = TLI.LowerCallTo(CLI);
return CallResult.second;
}
return SDValue();
}
bool AArch64SelectionDAGInfo::generateFMAsInMachineCombiner(
CodeGenOpt::Level OptLevel) const {
return OptLevel >= CodeGenOpt::Aggressive;
}
static const int kSetTagLoopThreshold = 176;
static SDValue EmitUnrolledSetTag(SelectionDAG &DAG, const SDLoc &dl,
SDValue Chain, SDValue Ptr, uint64_t ObjSize,
const MachineMemOperand *BaseMemOperand,
bool ZeroData) {
MachineFunction &MF = DAG.getMachineFunction();
unsigned ObjSizeScaled = ObjSize / 16;
SDValue TagSrc = Ptr;
if (Ptr.getOpcode() == ISD::FrameIndex) {
int FI = cast<FrameIndexSDNode>(Ptr)->getIndex();
Ptr = DAG.getTargetFrameIndex(FI, MVT::i64);
// A frame index operand may end up as [SP + offset] => it is fine to use SP
// register as the tag source.
TagSrc = DAG.getRegister(AArch64::SP, MVT::i64);
}
const unsigned OpCode1 = ZeroData ? AArch64ISD::STZG : AArch64ISD::STG;
const unsigned OpCode2 = ZeroData ? AArch64ISD::STZ2G : AArch64ISD::ST2G;
SmallVector<SDValue, 8> OutChains;
unsigned OffsetScaled = 0;
while (OffsetScaled < ObjSizeScaled) {
if (ObjSizeScaled - OffsetScaled >= 2) {
SDValue AddrNode = DAG.getMemBasePlusOffset(Ptr, OffsetScaled * 16, dl);
SDValue St = DAG.getMemIntrinsicNode(
OpCode2, dl, DAG.getVTList(MVT::Other),
{Chain, TagSrc, AddrNode},
MVT::v4i64,
MF.getMachineMemOperand(BaseMemOperand, OffsetScaled * 16, 16 * 2));
OffsetScaled += 2;
OutChains.push_back(St);
continue;
}
if (ObjSizeScaled - OffsetScaled > 0) {
SDValue AddrNode = DAG.getMemBasePlusOffset(Ptr, OffsetScaled * 16, dl);
SDValue St = DAG.getMemIntrinsicNode(
OpCode1, dl, DAG.getVTList(MVT::Other),
{Chain, TagSrc, AddrNode},
MVT::v2i64,
MF.getMachineMemOperand(BaseMemOperand, OffsetScaled * 16, 16));
OffsetScaled += 1;
OutChains.push_back(St);
}
}
SDValue Res = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, OutChains);
return Res;
}
SDValue AArch64SelectionDAGInfo::EmitTargetCodeForSetTag(
SelectionDAG &DAG, const SDLoc &dl, SDValue Chain, SDValue Addr,
SDValue Size, MachinePointerInfo DstPtrInfo, bool ZeroData) const {
uint64_t ObjSize = cast<ConstantSDNode>(Size)->getZExtValue();
assert(ObjSize % 16 == 0);
MachineFunction &MF = DAG.getMachineFunction();
MachineMemOperand *BaseMemOperand = MF.getMachineMemOperand(
DstPtrInfo, MachineMemOperand::MOStore, ObjSize, Align(16));
bool UseSetTagRangeLoop =
kSetTagLoopThreshold >= 0 && (int)ObjSize >= kSetTagLoopThreshold;
if (!UseSetTagRangeLoop)
return EmitUnrolledSetTag(DAG, dl, Chain, Addr, ObjSize, BaseMemOperand,
ZeroData);
const EVT ResTys[] = {MVT::i64, MVT::i64, MVT::Other};
unsigned Opcode;
if (Addr.getOpcode() == ISD::FrameIndex) {
int FI = cast<FrameIndexSDNode>(Addr)->getIndex();
Addr = DAG.getTargetFrameIndex(FI, MVT::i64);
Opcode = ZeroData ? AArch64::STZGloop : AArch64::STGloop;
} else {
Opcode = ZeroData ? AArch64::STZGloop_wback : AArch64::STGloop_wback;
}
SDValue Ops[] = {DAG.getTargetConstant(ObjSize, dl, MVT::i64), Addr, Chain};
SDNode *St = DAG.getMachineNode(Opcode, dl, ResTys, Ops);
DAG.setNodeMemRefs(cast<MachineSDNode>(St), {BaseMemOperand});
return SDValue(St, 2);
}