llvm-project/llvm/lib/Target/RISCV/RISCVExpandPseudoInsts.cpp

467 lines
16 KiB
C++

//===-- 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 expandCCOp(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandBarrier(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandCompareSelect(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI);
bool expandVIIMM11(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;
}
// TODO: Expand macro instruction with more than 32 registers here?
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.
if (RISCVII::isVOPIMM11(MBBI->getDesc().TSFlags))
return expandVIIMM11(MBB, MBBI);
switch (MBBI->getOpcode()) {
case RISCV::PseudoCCMOVGPR:
return expandCCOp(MBB, MBBI, NextMBBI);
case RISCV::PseudoBarrier:
case RISCV::PseudoSubGroupBarrier:
return expandBarrier(MBB, MBBI, NextMBBI);
case RISCV::PseudoVMSLTU_VI:
case RISCV::PseudoVMSLT_VI:
case RISCV::PseudoVMSGE_VI:
case RISCV::PseudoVMSGEU_VI:
return expandCompareSelect(MBB, MBBI, NextMBBI);
}
return false;
}
bool RISCVExpandPseudo::expandVIIMM11(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI) {
const TargetRegisterInfo *TRI =
MBB.getParent()->getSubtarget().getRegisterInfo();
const MCInstrDesc *MCID = nullptr;
switch (MBBI->getOpcode()) {
default:
llvm_unreachable("Please add IMM11 Pseudo case here!");
case RISCV::PseudoVOR_VI_IMM11:
MCID = &TII->get(RISCV::VOR_VI);
break;
case RISCV::PseudoVXOR_VI_IMM11:
MCID = &TII->get(RISCV::VXOR_VI);
break;
case RISCV::PseudoVRSUB_VI_IMM11:
MCID = &TII->get(RISCV::VRSUB_VI);
break;
case RISCV::PseudoVAND_VI_IMM11:
MCID = &TII->get(RISCV::VAND_VI);
break;
case RISCV::PseudoVMSNE_VI_IMM11:
MCID = &TII->get(RISCV::VMSNE_VI);
break;
case RISCV::PseudoVMSEQ_VI_IMM11:
MCID = &TII->get(RISCV::VMSEQ_VI);
break;
}
assert(MCID && "Unexpected opcode");
MBBI->setDesc(*MCID);
int64_t Imm = 0;
signed LowImm = 0;
signed HighImm = 0;
unsigned uImm = 0;
signed Offsets = 0;
for (unsigned i = 0; i < MBBI->getNumOperands(); ++i) {
MachineOperand &Op = MBBI->getOperand(i);
if (Op.isImm()) {
Imm = Op.getImm();
assert((Imm <= 1023 && Imm >= -1024) && "imm not in Imm11 range!");
uImm = Imm & 0x7FF;
unsigned uLowImm = uImm & 0x1F;
if (uLowImm & 0x10) {
if (uLowImm == 0x10) {
LowImm = -16;
} else {
LowImm = -(((~uLowImm) + 1) & 0x1F);
}
} else {
LowImm = uLowImm;
}
unsigned uHighImm = (uImm >> 5) & 0x3F;
if (uHighImm & 0x20) {
if (uHighImm == 0x20) {
HighImm = -32;
} else {
HighImm = -(((~uHighImm) + 1) & 0x3F);
}
} else {
HighImm = uHighImm;
}
Op.ChangeToImmediate(LowImm);
continue;
}
if (!Op.isReg() ||
MBBI->getDesc().getOperandConstraint(i, MCOI::TIED_TO) != -1)
continue;
// deal with register numbers larger than 32.
if (Op.isReg() &&
MBBI->getDesc().getOperandConstraint(i, MCOI::TIED_TO) == -1) {
uint16_t RegEncodingValue = TRI->getEncodingValue(Op.getReg());
if (RegEncodingValue > 31) {
int Pos = MBBI->getDesc().getOperandConstraint(i, MCOI::CUSTOM);
assert(Pos != -1 && "Out of range[0, 31] register operand custom "
"constraint that must be present.");
assert(Pos != 1 && Pos != 3 && "Unexpected Pos!");
Offsets |= (RegEncodingValue >> 5 & 0x7) << (3 * (Pos == 2 ? 1 : Pos));
}
}
}
DebugLoc DL = MBBI->getDebugLoc();
// Create instruction to expand imm5 or register basic offset as imm * 32.
BuildMI(MBB, MBBI, DL, TII->get(RISCV::REGEXTI), RISCV::X0)
.addReg(RISCV::X0)
.addImm((HighImm << 6) | Offsets);
return true;
}
bool RISCVExpandPseudo::expandBarrier(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
assert((MBBI->getOpcode() == RISCV::PseudoBarrier ||
MBBI->getOpcode() == RISCV::PseudoSubGroupBarrier) &&
"Unexpected opcode");
bool isBarrier = MBBI->getOpcode() == RISCV::PseudoBarrier;
unsigned BarrierOpcode = isBarrier ? RISCV::BARRIER : RISCV::SUBGROUP_BARRIER;
uint32_t MemFlag = MBBI->getOperand(0).getImm();
// when use barriersub, MemScope is default to be 0
uint32_t MemScope = isBarrier ? MBBI->getOperand(1).getImm() : 0;
BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII->get(BarrierOpcode))
.addImm((MemScope << 3) + MemFlag);
MBBI->eraseFromParent();
return true;
}
bool RISCVExpandPseudo::expandCompareSelect(
MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
unsigned Opcode = MBBI->getOpcode();
if (Opcode == RISCV::PseudoVMSLT_VI) {
Opcode = RISCV::VMSLE_VI;
} else if (Opcode == RISCV::PseudoVMSLTU_VI) {
Opcode = RISCV::VMSLEU_VI;
} else if (Opcode == RISCV::PseudoVMSGE_VI) {
Opcode = RISCV::VMSGT_VI;
} else if (Opcode == RISCV::PseudoVMSGEU_VI) {
Opcode = RISCV::VMSGTU_VI;
} else {
llvm_unreachable("Unexpected Opcode!");
}
BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII->get(Opcode),
MBBI->getOperand(0).getReg())
.addReg(MBBI->getOperand(1).getReg())
.addImm(MBBI->getOperand(2).getImm() - 1);
MBBI->eraseFromParent();
return true;
}
bool RISCVExpandPseudo::expandCCOp(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
MachineBasicBlock::iterator &NextMBBI) {
assert(MBBI->getOpcode() == RISCV::PseudoCCMOVGPR && "Unexpected opcode");
MachineFunction *MF = MBB.getParent();
MachineInstr &MI = *MBBI;
DebugLoc DL = MI.getDebugLoc();
MachineBasicBlock *TrueBB = MF->CreateMachineBasicBlock(MBB.getBasicBlock());
MachineBasicBlock *MergeBB = MF->CreateMachineBasicBlock(MBB.getBasicBlock());
MF->insert(++MBB.getIterator(), TrueBB);
MF->insert(++TrueBB->getIterator(), MergeBB);
// We want to copy the "true" value when the condition is true which means
// we need to invert the branch condition to jump over TrueBB when the
// condition is false.
auto CC = static_cast<RISCVCC::CondCode>(MI.getOperand(3).getImm());
CC = RISCVCC::getOppositeBranchCondition(CC);
// Insert branch instruction.
BuildMI(MBB, MBBI, DL, TII->getBrCond(CC))
.addReg(MI.getOperand(1).getReg())
.addReg(MI.getOperand(2).getReg())
.addMBB(MergeBB);
Register DestReg = MI.getOperand(0).getReg();
assert(MI.getOperand(4).getReg() == DestReg);
// Add MV.
BuildMI(TrueBB, DL, TII->get(RISCV::ADDI), DestReg)
.add(MI.getOperand(5))
.addImm(0);
TrueBB->addSuccessor(MergeBB);
MergeBB->splice(MergeBB->end(), &MBB, MI, MBB.end());
MergeBB->transferSuccessors(&MBB);
MBB.addSuccessor(TrueBB);
MBB.addSuccessor(MergeBB);
NextMBBI = MBB.end();
MI.eraseFromParent();
// Make sure live-ins are correctly attached to this new basic block.
LivePhysRegs LiveRegs;
computeAndAddLiveIns(LiveRegs, *TrueBB);
computeAndAddLiveIns(LiveRegs, *MergeBB);
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