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llvm-project/llvm/lib/Target/Mips/Mips16ISelDAGToDAG.cpp

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//===-- Mips16ISelDAGToDAG.cpp - A Dag to Dag Inst Selector for Mips16 ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Subclass of MipsDAGToDAGISel specialized for mips16.
//
//===----------------------------------------------------------------------===//
#include "Mips16ISelDAGToDAG.h"
#include "MCTargetDesc/MipsBaseInfo.h"
#include "Mips.h"
#include "MipsAnalyzeImmediate.h"
#include "MipsMachineFunction.h"
#include "MipsRegisterInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "mips-isel"
bool Mips16DAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
Subtarget = &static_cast<const MipsSubtarget &>(MF.getSubtarget());
if (!Subtarget->inMips16Mode())
return false;
return MipsDAGToDAGISel::runOnMachineFunction(MF);
}
/// Select multiply instructions.
std::pair<SDNode*, SDNode*>
Mips16DAGToDAGISel::selectMULT(SDNode *N, unsigned Opc, SDLoc DL, EVT Ty,
bool HasLo, bool HasHi) {
SDNode *Lo = nullptr, *Hi = nullptr;
SDNode *Mul = CurDAG->getMachineNode(Opc, DL, MVT::Glue, N->getOperand(0),
N->getOperand(1));
SDValue InFlag = SDValue(Mul, 0);
if (HasLo) {
unsigned Opcode = Mips::Mflo16;
Lo = CurDAG->getMachineNode(Opcode, DL, Ty, MVT::Glue, InFlag);
InFlag = SDValue(Lo, 1);
}
if (HasHi) {
unsigned Opcode = Mips::Mfhi16;
Hi = CurDAG->getMachineNode(Opcode, DL, Ty, InFlag);
}
return std::make_pair(Lo, Hi);
}
void Mips16DAGToDAGISel::initGlobalBaseReg(MachineFunction &MF) {
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
if (!MipsFI->globalBaseRegSet())
return;
MachineBasicBlock &MBB = MF.front();
MachineBasicBlock::iterator I = MBB.begin();
MachineRegisterInfo &RegInfo = MF.getRegInfo();
const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
DebugLoc DL;
unsigned V0, V1, V2, GlobalBaseReg = MipsFI->getGlobalBaseReg();
const TargetRegisterClass *RC = &Mips::CPU16RegsRegClass;
V0 = RegInfo.createVirtualRegister(RC);
V1 = RegInfo.createVirtualRegister(RC);
V2 = RegInfo.createVirtualRegister(RC);
BuildMI(MBB, I, DL, TII.get(Mips::GotPrologue16), V0).
addReg(V1, RegState::Define).
addExternalSymbol("_gp_disp", MipsII::MO_ABS_HI).
addExternalSymbol("_gp_disp", MipsII::MO_ABS_LO);
BuildMI(MBB, I, DL, TII.get(Mips::SllX16), V2).addReg(V0).addImm(16);
BuildMI(MBB, I, DL, TII.get(Mips::AdduRxRyRz16), GlobalBaseReg)
.addReg(V1).addReg(V2);
}
// Insert instructions to initialize the Mips16 SP Alias register in the
// first MBB of the function.
//
void Mips16DAGToDAGISel::initMips16SPAliasReg(MachineFunction &MF) {
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
if (!MipsFI->mips16SPAliasRegSet())
return;
MachineBasicBlock &MBB = MF.front();
MachineBasicBlock::iterator I = MBB.begin();
const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
unsigned Mips16SPAliasReg = MipsFI->getMips16SPAliasReg();
BuildMI(MBB, I, DL, TII.get(Mips::MoveR3216), Mips16SPAliasReg)
.addReg(Mips::SP);
}
void Mips16DAGToDAGISel::processFunctionAfterISel(MachineFunction &MF) {
initGlobalBaseReg(MF);
initMips16SPAliasReg(MF);
}
/// getMips16SPAliasReg - Output the instructions required to put the
/// SP into a Mips16 accessible aliased register.
SDValue Mips16DAGToDAGISel::getMips16SPAliasReg() {
unsigned Mips16SPAliasReg =
MF->getInfo<MipsFunctionInfo>()->getMips16SPAliasReg();
auto PtrVT = getTargetLowering()->getPointerTy(CurDAG->getDataLayout());
return CurDAG->getRegister(Mips16SPAliasReg, PtrVT);
}
void Mips16DAGToDAGISel::getMips16SPRefReg(SDNode *Parent, SDValue &AliasReg) {
auto PtrVT = getTargetLowering()->getPointerTy(CurDAG->getDataLayout());
SDValue AliasFPReg = CurDAG->getRegister(Mips::S0, PtrVT);
if (Parent) {
switch (Parent->getOpcode()) {
case ISD::LOAD: {
LoadSDNode *SD = dyn_cast<LoadSDNode>(Parent);
switch (SD->getMemoryVT().getSizeInBits()) {
case 8:
case 16:
AliasReg = Subtarget->getFrameLowering()->hasFP(*MF)
? AliasFPReg
: getMips16SPAliasReg();
return;
}
break;
}
case ISD::STORE: {
StoreSDNode *SD = dyn_cast<StoreSDNode>(Parent);
switch (SD->getMemoryVT().getSizeInBits()) {
case 8:
case 16:
AliasReg = Subtarget->getFrameLowering()->hasFP(*MF)
? AliasFPReg
: getMips16SPAliasReg();
return;
}
break;
}
}
}
AliasReg = CurDAG->getRegister(Mips::SP, PtrVT);
return;
}
bool Mips16DAGToDAGISel::selectAddr16(
SDNode *Parent, SDValue Addr, SDValue &Base, SDValue &Offset,
SDValue &Alias) {
SDLoc DL(Addr);
EVT ValTy = Addr.getValueType();
Alias = CurDAG->getTargetConstant(0, DL, ValTy);
// if Address is FI, get the TargetFrameIndex.
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>(Addr)) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
Offset = CurDAG->getTargetConstant(0, DL, ValTy);
getMips16SPRefReg(Parent, Alias);
return true;
}
// on PIC code Load GA
if (Addr.getOpcode() == MipsISD::Wrapper) {
Base = Addr.getOperand(0);
Offset = Addr.getOperand(1);
return true;
}
if (TM.getRelocationModel() != Reloc::PIC_) {
if ((Addr.getOpcode() == ISD::TargetExternalSymbol ||
Addr.getOpcode() == ISD::TargetGlobalAddress))
return false;
}
// Addresses of the form FI+const or FI|const
if (CurDAG->isBaseWithConstantOffset(Addr)) {
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Addr.getOperand(1));
if (isInt<16>(CN->getSExtValue())) {
// If the first operand is a FI, get the TargetFI Node
if (FrameIndexSDNode *FIN = dyn_cast<FrameIndexSDNode>
(Addr.getOperand(0))) {
Base = CurDAG->getTargetFrameIndex(FIN->getIndex(), ValTy);
getMips16SPRefReg(Parent, Alias);
}
else
Base = Addr.getOperand(0);
Offset = CurDAG->getTargetConstant(CN->getZExtValue(), DL, ValTy);
return true;
}
}
// Operand is a result from an ADD.
if (Addr.getOpcode() == ISD::ADD) {
// When loading from constant pools, load the lower address part in
// the instruction itself. Example, instead of:
// lui $2, %hi($CPI1_0)
// addiu $2, $2, %lo($CPI1_0)
// lwc1 $f0, 0($2)
// Generate:
// lui $2, %hi($CPI1_0)
// lwc1 $f0, %lo($CPI1_0)($2)
if (Addr.getOperand(1).getOpcode() == MipsISD::Lo ||
Addr.getOperand(1).getOpcode() == MipsISD::GPRel) {
SDValue Opnd0 = Addr.getOperand(1).getOperand(0);
if (isa<ConstantPoolSDNode>(Opnd0) || isa<GlobalAddressSDNode>(Opnd0) ||
isa<JumpTableSDNode>(Opnd0)) {
Base = Addr.getOperand(0);
Offset = Opnd0;
return true;
}
}
// If an indexed floating point load/store can be emitted, return false.
const LSBaseSDNode *LS = dyn_cast<LSBaseSDNode>(Parent);
if (LS) {
if (LS->getMemoryVT() == MVT::f32 && Subtarget->hasMips4_32r2())
return false;
if (LS->getMemoryVT() == MVT::f64 && Subtarget->hasMips4_32r2())
return false;
}
}
Base = Addr;
Offset = CurDAG->getTargetConstant(0, DL, ValTy);
return true;
}
/// Select instructions not customized! Used for
/// expanded, promoted and normal instructions
std::pair<bool, SDNode*> Mips16DAGToDAGISel::selectNode(SDNode *Node) {
unsigned Opcode = Node->getOpcode();
SDLoc DL(Node);
///
// Instruction Selection not handled by the auto-generated
// tablegen selection should be handled here.
///
EVT NodeTy = Node->getValueType(0);
unsigned MultOpc;
switch(Opcode) {
default: break;
case ISD::SUBE:
case ISD::ADDE: {
SDValue InFlag = Node->getOperand(2), CmpLHS;
unsigned Opc = InFlag.getOpcode(); (void)Opc;
assert(((Opc == ISD::ADDC || Opc == ISD::ADDE) ||
(Opc == ISD::SUBC || Opc == ISD::SUBE)) &&
"(ADD|SUB)E flag operand must come from (ADD|SUB)C/E insn");
unsigned MOp;
if (Opcode == ISD::ADDE) {
CmpLHS = InFlag.getValue(0);
MOp = Mips::AdduRxRyRz16;
} else {
CmpLHS = InFlag.getOperand(0);
MOp = Mips::SubuRxRyRz16;
}
SDValue Ops[] = { CmpLHS, InFlag.getOperand(1) };
SDValue LHS = Node->getOperand(0);
SDValue RHS = Node->getOperand(1);
EVT VT = LHS.getValueType();
unsigned Sltu_op = Mips::SltuRxRyRz16;
SDNode *Carry = CurDAG->getMachineNode(Sltu_op, DL, VT, Ops);
unsigned Addu_op = Mips::AdduRxRyRz16;
SDNode *AddCarry = CurDAG->getMachineNode(Addu_op, DL, VT,
SDValue(Carry,0), RHS);
SDNode *Result = CurDAG->SelectNodeTo(Node, MOp, VT, MVT::Glue, LHS,
SDValue(AddCarry,0));
return std::make_pair(true, Result);
}
/// Mul with two results
case ISD::SMUL_LOHI:
case ISD::UMUL_LOHI: {
MultOpc = (Opcode == ISD::UMUL_LOHI ? Mips::MultuRxRy16 : Mips::MultRxRy16);
std::pair<SDNode*, SDNode*> LoHi = selectMULT(Node, MultOpc, DL, NodeTy,
true, true);
if (!SDValue(Node, 0).use_empty())
ReplaceUses(SDValue(Node, 0), SDValue(LoHi.first, 0));
if (!SDValue(Node, 1).use_empty())
ReplaceUses(SDValue(Node, 1), SDValue(LoHi.second, 0));
return std::make_pair(true, nullptr);
}
case ISD::MULHS:
case ISD::MULHU: {
MultOpc = (Opcode == ISD::MULHU ? Mips::MultuRxRy16 : Mips::MultRxRy16);
SDNode *Result = selectMULT(Node, MultOpc, DL, NodeTy, false, true).second;
return std::make_pair(true, Result);
}
}
return std::make_pair(false, nullptr);
}
FunctionPass *llvm::createMips16ISelDag(MipsTargetMachine &TM) {
return new Mips16DAGToDAGISel(TM);
}
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