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//===-- RISCVExpandPseudoInsts.cpp - Expand pseudo instructions -----------===//
//
// 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 contains a pass that expands pseudo instructions into target
// instructions. This pass should be run after register allocation but before
// the post-regalloc scheduling pass.
//
//===----------------------------------------------------------------------===//
#include "RISCV.h"
#include "RISCVInstrInfo.h"
#include "RISCVTargetMachine.h"
#include "llvm/CodeGen/LivePhysRegs.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/MC/MCContext.h"
using namespace llvm;
#define RISCV_EXPAND_PSEUDO_NAME "RISCV pseudo instruction expansion pass"
#define RISCV_PRERA_EXPAND_PSEUDO_NAME "RISCV Pre-RA pseudo instruction expansion pass"
namespace {
class RISCVExpandPseudo : public MachineFunctionPass {
public:
const RISCVInstrInfo *TII;
static char ID;
RISCVExpandPseudo() : MachineFunctionPass(ID) {
initializeRISCVExpandPseudoPass(*PassRegistry::getPassRegistry());
}
bool runOnMachineFunction(MachineFunction &MF) override;
StringRef getPassName() const override { return RISCV_EXPAND_PSEUDO_NAME; }
private:
bool expandMBB(MachineBasicBlock &MBB);
bool expandMI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandVSetVL(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
bool expandVMSET_VMCLR(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, unsigned Opcode);
bool expandVSPILL(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
bool expandVRELOAD(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
};
char RISCVExpandPseudo::ID = 0;
bool RISCVExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
TII = static_cast<const RISCVInstrInfo *>(MF.getSubtarget().getInstrInfo());
bool Modified = false;
for (auto &MBB : MF)
Modified |= expandMBB(MBB);
return Modified;
}
bool RISCVExpandPseudo::expandMBB(MachineBasicBlock &MBB) {
bool Modified = false;
MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
while (MBBI != E) {
MachineBasicBlock::iterator NMBBI = std::next(MBBI);
Modified |= expandMI(MBB, MBBI, NMBBI);
MBBI = NMBBI;
}
return Modified;
}
bool RISCVExpandPseudo::expandMI(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
// RISCVInstrInfo::getInstSizeInBytes expects that the total size of the
// expanded instructions for each pseudo is correct in the Size field of the
// tablegen definition for the pseudo.
switch (MBBI->getOpcode()) {
case RISCV::PseudoVSETVLI:
case RISCV::PseudoVSETVLIX0:
case RISCV::PseudoVSETIVLI:
return expandVSetVL(MBB, MBBI);
case RISCV::PseudoVMCLR_M_B1:
case RISCV::PseudoVMCLR_M_B2:
case RISCV::PseudoVMCLR_M_B4:
case RISCV::PseudoVMCLR_M_B8:
case RISCV::PseudoVMCLR_M_B16:
case RISCV::PseudoVMCLR_M_B32:
case RISCV::PseudoVMCLR_M_B64:
// vmclr.m vd => vmxor.mm vd, vd, vd
return expandVMSET_VMCLR(MBB, MBBI, RISCV::VMXOR_MM);
case RISCV::PseudoVMSET_M_B1:
case RISCV::PseudoVMSET_M_B2:
case RISCV::PseudoVMSET_M_B4:
case RISCV::PseudoVMSET_M_B8:
case RISCV::PseudoVMSET_M_B16:
case RISCV::PseudoVMSET_M_B32:
case RISCV::PseudoVMSET_M_B64:
// vmset.m vd => vmxnor.mm vd, vd, vd
return expandVMSET_VMCLR(MBB, MBBI, RISCV::VMXNOR_MM);
case RISCV::PseudoVSPILL2_M1:
case RISCV::PseudoVSPILL2_M2:
case RISCV::PseudoVSPILL2_M4:
case RISCV::PseudoVSPILL3_M1:
case RISCV::PseudoVSPILL3_M2:
case RISCV::PseudoVSPILL4_M1:
case RISCV::PseudoVSPILL4_M2:
case RISCV::PseudoVSPILL5_M1:
case RISCV::PseudoVSPILL6_M1:
case RISCV::PseudoVSPILL7_M1:
case RISCV::PseudoVSPILL8_M1:
return expandVSPILL(MBB, MBBI);
case RISCV::PseudoVRELOAD2_M1:
case RISCV::PseudoVRELOAD2_M2:
case RISCV::PseudoVRELOAD2_M4:
case RISCV::PseudoVRELOAD3_M1:
case RISCV::PseudoVRELOAD3_M2:
case RISCV::PseudoVRELOAD4_M1:
case RISCV::PseudoVRELOAD4_M2:
case RISCV::PseudoVRELOAD5_M1:
case RISCV::PseudoVRELOAD6_M1:
case RISCV::PseudoVRELOAD7_M1:
case RISCV::PseudoVRELOAD8_M1:
return expandVRELOAD(MBB, MBBI);
}
return false;
}
bool RISCVExpandPseudo::expandVSetVL(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI) {
assert(MBBI->getNumExplicitOperands() == 3 && MBBI->getNumOperands() >= 5 &&
"Unexpected instruction format");
DebugLoc DL = MBBI->getDebugLoc();
assert((MBBI->getOpcode() == RISCV::PseudoVSETVLI ||
MBBI->getOpcode() == RISCV::PseudoVSETVLIX0 ||
MBBI->getOpcode() == RISCV::PseudoVSETIVLI) &&
"Unexpected pseudo instruction");
unsigned Opcode;
if (MBBI->getOpcode() == RISCV::PseudoVSETIVLI)
Opcode = RISCV::VSETIVLI;
else
Opcode = RISCV::VSETVLI;
const MCInstrDesc &Desc = TII->get(Opcode);
assert(Desc.getNumOperands() == 3 && "Unexpected instruction format");
Register DstReg = MBBI->getOperand(0).getReg();
bool DstIsDead = MBBI->getOperand(0).isDead();
BuildMI(MBB, MBBI, DL, Desc)
.addReg(DstReg, RegState::Define | getDeadRegState(DstIsDead))
.add(MBBI->getOperand(1)) // VL
.add(MBBI->getOperand(2)); // VType
MBBI->eraseFromParent(); // The pseudo instruction is gone now.
return true;
}
bool RISCVExpandPseudo::expandVMSET_VMCLR(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned Opcode) {
DebugLoc DL = MBBI->getDebugLoc();
Register DstReg = MBBI->getOperand(0).getReg();
const MCInstrDesc &Desc = TII->get(Opcode);
BuildMI(MBB, MBBI, DL, Desc, DstReg)
.addReg(DstReg, RegState::Undef)
.addReg(DstReg, RegState::Undef);
MBBI->eraseFromParent(); // The pseudo instruction is gone now.
return true;
}
bool RISCVExpandPseudo::expandVSPILL(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI) {
const TargetRegisterInfo *TRI =
MBB.getParent()->getSubtarget().getRegisterInfo();
DebugLoc DL = MBBI->getDebugLoc();
Register SrcReg = MBBI->getOperand(0).getReg();
Register Base = MBBI->getOperand(1).getReg();
Register VL = MBBI->getOperand(2).getReg();
auto ZvlssegInfo = RISCV::isRVVSpillForZvlsseg(MBBI->getOpcode());
if (!ZvlssegInfo)
return false;
unsigned NF = ZvlssegInfo->first;
unsigned LMUL = ZvlssegInfo->second;
assert(NF * LMUL <= 8 && "Invalid NF/LMUL combinations.");
unsigned Opcode = RISCV::VS1R_V;
unsigned SubRegIdx = RISCV::sub_vrm1_0;
static_assert(RISCV::sub_vrm1_7 == RISCV::sub_vrm1_0 + 7,
"Unexpected subreg numbering");
if (LMUL == 2) {
Opcode = RISCV::VS2R_V;
SubRegIdx = RISCV::sub_vrm2_0;
static_assert(RISCV::sub_vrm2_3 == RISCV::sub_vrm2_0 + 3,
"Unexpected subreg numbering");
} else if (LMUL == 4) {
Opcode = RISCV::VS4R_V;
SubRegIdx = RISCV::sub_vrm4_0;
static_assert(RISCV::sub_vrm4_1 == RISCV::sub_vrm4_0 + 1,
"Unexpected subreg numbering");
} else
assert(LMUL == 1 && "LMUL must be 1, 2, or 4.");
for (unsigned I = 0; I < NF; ++I) {
// Adding implicit-use of super register to describe we are using part of
// super register, that prevents machine verifier complaining when part of
// subreg is undef, see comment in MachineVerifier::checkLiveness for more
// detail.
BuildMI(MBB, MBBI, DL, TII->get(Opcode))
.addReg(TRI->getSubReg(SrcReg, SubRegIdx + I))
.addReg(Base)
.addMemOperand(*(MBBI->memoperands_begin()))
.addReg(SrcReg, RegState::Implicit);
if (I != NF - 1)
BuildMI(MBB, MBBI, DL, TII->get(RISCV::ADD), Base)
.addReg(Base)
.addReg(VL);
}
MBBI->eraseFromParent();
return true;
}
bool RISCVExpandPseudo::expandVRELOAD(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI) {
const TargetRegisterInfo *TRI =
MBB.getParent()->getSubtarget().getRegisterInfo();
DebugLoc DL = MBBI->getDebugLoc();
Register DestReg = MBBI->getOperand(0).getReg();
Register Base = MBBI->getOperand(1).getReg();
Register VL = MBBI->getOperand(2).getReg();
auto ZvlssegInfo = RISCV::isRVVSpillForZvlsseg(MBBI->getOpcode());
if (!ZvlssegInfo)
return false;
unsigned NF = ZvlssegInfo->first;
unsigned LMUL = ZvlssegInfo->second;
assert(NF * LMUL <= 8 && "Invalid NF/LMUL combinations.");
unsigned Opcode = RISCV::VL1RE8_V;
unsigned SubRegIdx = RISCV::sub_vrm1_0;
static_assert(RISCV::sub_vrm1_7 == RISCV::sub_vrm1_0 + 7,
"Unexpected subreg numbering");
if (LMUL == 2) {
Opcode = RISCV::VL2RE8_V;
SubRegIdx = RISCV::sub_vrm2_0;
static_assert(RISCV::sub_vrm2_3 == RISCV::sub_vrm2_0 + 3,
"Unexpected subreg numbering");
} else if (LMUL == 4) {
Opcode = RISCV::VL4RE8_V;
SubRegIdx = RISCV::sub_vrm4_0;
static_assert(RISCV::sub_vrm4_1 == RISCV::sub_vrm4_0 + 1,
"Unexpected subreg numbering");
} else
assert(LMUL == 1 && "LMUL must be 1, 2, or 4.");
for (unsigned I = 0; I < NF; ++I) {
BuildMI(MBB, MBBI, DL, TII->get(Opcode),
TRI->getSubReg(DestReg, SubRegIdx + I))
.addReg(Base)
.addMemOperand(*(MBBI->memoperands_begin()));
if (I != NF - 1)
BuildMI(MBB, MBBI, DL, TII->get(RISCV::ADD), Base)
.addReg(Base)
.addReg(VL);
}
MBBI->eraseFromParent();
return true;
}
class RISCVPreRAExpandPseudo : public MachineFunctionPass {
public:
const RISCVInstrInfo *TII;
static char ID;
RISCVPreRAExpandPseudo() : MachineFunctionPass(ID) {
initializeRISCVPreRAExpandPseudoPass(*PassRegistry::getPassRegistry());
}
bool runOnMachineFunction(MachineFunction &MF) override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
StringRef getPassName() const override {
return RISCV_PRERA_EXPAND_PSEUDO_NAME;
}
private:
bool expandMBB(MachineBasicBlock &MBB);
bool expandMI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandAuipcInstPair(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI,
unsigned FlagsHi, unsigned SecondOpcode);
bool expandLoadLocalAddress(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandLoadAddress(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandLoadTLSIEAddress(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandLoadTLSGDAddress(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
};
char RISCVPreRAExpandPseudo::ID = 0;
bool RISCVPreRAExpandPseudo::runOnMachineFunction(MachineFunction &MF) {
TII = static_cast<const RISCVInstrInfo *>(MF.getSubtarget().getInstrInfo());
bool Modified = false;
for (auto &MBB : MF)
Modified |= expandMBB(MBB);
return Modified;
}
bool RISCVPreRAExpandPseudo::expandMBB(MachineBasicBlock &MBB) {
bool Modified = false;
MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
while (MBBI != E) {
MachineBasicBlock::iterator NMBBI = std::next(MBBI);
Modified |= expandMI(MBB, MBBI, NMBBI);
MBBI = NMBBI;
}
return Modified;
}
bool RISCVPreRAExpandPseudo::expandMI(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
switch (MBBI->getOpcode()) {
case RISCV::PseudoLLA:
return expandLoadLocalAddress(MBB, MBBI, NextMBBI);
case RISCV::PseudoLA:
return expandLoadAddress(MBB, MBBI, NextMBBI);
case RISCV::PseudoLA_TLS_IE:
return expandLoadTLSIEAddress(MBB, MBBI, NextMBBI);
case RISCV::PseudoLA_TLS_GD:
return expandLoadTLSGDAddress(MBB, MBBI, NextMBBI);
}
return false;
}
bool RISCVPreRAExpandPseudo::expandAuipcInstPair(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI, unsigned FlagsHi,
unsigned SecondOpcode) {
MachineFunction *MF = MBB.getParent();
MachineInstr &MI = *MBBI;
DebugLoc DL = MI.getDebugLoc();
Register DestReg = MI.getOperand(0).getReg();
Register ScratchReg =
MF->getRegInfo().createVirtualRegister(&RISCV::GPRRegClass);
MachineOperand &Symbol = MI.getOperand(1);
Symbol.setTargetFlags(FlagsHi);
MCSymbol *AUIPCSymbol = MF->getContext().createNamedTempSymbol("pcrel_hi");
MachineInstr *MIAUIPC =
BuildMI(MBB, MBBI, DL, TII->get(RISCV::AUIPC), ScratchReg).add(Symbol);
MIAUIPC->setPreInstrSymbol(*MF, AUIPCSymbol);
MachineInstr *SecondMI =
BuildMI(MBB, MBBI, DL, TII->get(SecondOpcode), DestReg)
.addReg(ScratchReg)
.addSym(AUIPCSymbol, RISCVII::MO_PCREL_LO);
if (MI.hasOneMemOperand())
SecondMI->addMemOperand(*MF, *MI.memoperands_begin());
MI.eraseFromParent();
return true;
}
bool RISCVPreRAExpandPseudo::expandLoadLocalAddress(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
return expandAuipcInstPair(MBB, MBBI, NextMBBI, RISCVII::MO_PCREL_HI,
RISCV::ADDI);
}
bool RISCVPreRAExpandPseudo::expandLoadAddress(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
MachineFunction *MF = MBB.getParent();
assert(MF->getTarget().isPositionIndependent());
const auto &STI = MF->getSubtarget<RISCVSubtarget>();
unsigned SecondOpcode = STI.is64Bit() ? RISCV::LD : RISCV::LW;
return expandAuipcInstPair(MBB, MBBI, NextMBBI, RISCVII::MO_GOT_HI,
SecondOpcode);
}
bool RISCVPreRAExpandPseudo::expandLoadTLSIEAddress(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
MachineFunction *MF = MBB.getParent();
const auto &STI = MF->getSubtarget<RISCVSubtarget>();
unsigned SecondOpcode = STI.is64Bit() ? RISCV::LD : RISCV::LW;
return expandAuipcInstPair(MBB, MBBI, NextMBBI, RISCVII::MO_TLS_GOT_HI,
SecondOpcode);
}
bool RISCVPreRAExpandPseudo::expandLoadTLSGDAddress(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
return expandAuipcInstPair(MBB, MBBI, NextMBBI, RISCVII::MO_TLS_GD_HI,
RISCV::ADDI);
}
} // end of anonymous namespace
INITIALIZE_PASS(RISCVExpandPseudo, "riscv-expand-pseudo",
RISCV_EXPAND_PSEUDO_NAME, false, false)
INITIALIZE_PASS(RISCVPreRAExpandPseudo, "riscv-prera-expand-pseudo",
RISCV_PRERA_EXPAND_PSEUDO_NAME, false, false)
namespace llvm {
FunctionPass *createRISCVExpandPseudoPass() { return new RISCVExpandPseudo(); }
FunctionPass *createRISCVPreRAExpandPseudoPass() { return new RISCVPreRAExpandPseudo(); }
} // end of namespace llvm