//===- SIPeepholeSDWA.cpp - Peephole optimization for SDWA instructions ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file This pass tries to apply several peephole SDWA patterns.
///
/// E.g. original:
/// V_LSHRREV_B32_e32 %0, 16, %1
/// V_ADD_I32_e32 %2, %0, %3
/// V_LSHLREV_B32_e32 %4, 16, %2
///
/// Replace:
/// V_ADD_I32_sdwa %4, %1, %3
/// dst_sel:WORD_1 dst_unused:UNUSED_PAD src0_sel:WORD_1 src1_sel:DWORD
///
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "AMDGPUSubtarget.h"
#include "SIDefines.h"
#include "SIInstrInfo.h"
#include "SIRegisterInfo.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "Utils/AMDGPUBaseInfo.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/MC/LaneBitmask.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <memory>
#include <unordered_map>
using namespace llvm;
#define DEBUG_TYPE "si-peephole-sdwa"
STATISTIC(NumSDWAPatternsFound, "Number of SDWA patterns found.");
STATISTIC(NumSDWAInstructionsPeepholed,
"Number of instruction converted to SDWA.");
namespace {
class SDWAOperand;
class SDWADstOperand;
class SIPeepholeSDWA : public MachineFunctionPass {
public:
using SDWAOperandsVector = SmallVector<SDWAOperand *, 4>;
private:
MachineRegisterInfo *MRI;
const SIRegisterInfo *TRI;
const SIInstrInfo *TII;
std::unordered_map<MachineInstr *, std::unique_ptr<SDWAOperand>> SDWAOperands;
std::unordered_map<MachineInstr *, SDWAOperandsVector> PotentialMatches;
SmallVector<MachineInstr *, 8> ConvertedInstructions;
Optional<int64_t> foldToImm(const MachineOperand &Op) const;
public:
static char ID;
SIPeepholeSDWA() : MachineFunctionPass(ID) {
initializeSIPeepholeSDWAPass(*PassRegistry::getPassRegistry());
}
bool runOnMachineFunction(MachineFunction &MF) override;
void matchSDWAOperands(MachineBasicBlock &MBB);
std::unique_ptr<SDWAOperand> matchSDWAOperand(MachineInstr &MI);
bool isConvertibleToSDWA(const MachineInstr &MI, const GCNSubtarget &ST) const;
bool convertToSDWA(MachineInstr &MI, const SDWAOperandsVector &SDWAOperands);
void legalizeScalarOperands(MachineInstr &MI, const GCNSubtarget &ST) const;
StringRef getPassName() const override { return "SI Peephole SDWA"; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
};
class SDWAOperand {
private:
MachineOperand *Target; // Operand that would be used in converted instruction
MachineOperand *Replaced; // Operand that would be replace by Target
public:
SDWAOperand(MachineOperand *TargetOp, MachineOperand *ReplacedOp)
: Target(TargetOp), Replaced(ReplacedOp) {
assert(Target->isReg());
assert(Replaced->isReg());
}
virtual ~SDWAOperand() = default;
virtual MachineInstr *potentialToConvert(const SIInstrInfo *TII) = 0;
virtual bool convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) = 0;
MachineOperand *getTargetOperand() const { return Target; }
MachineOperand *getReplacedOperand() const { return Replaced; }
MachineInstr *getParentInst() const { return Target->getParent(); }
MachineRegisterInfo *getMRI() const {
return &getParentInst()->getParent()->getParent()->getRegInfo();
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
virtual void print(raw_ostream& OS) const = 0;
void dump() const { print(dbgs()); }
#endif
};
using namespace AMDGPU::SDWA;
class SDWASrcOperand : public SDWAOperand {
private:
SdwaSel SrcSel;
bool Abs;
bool Neg;
bool Sext;
public:
SDWASrcOperand(MachineOperand *TargetOp, MachineOperand *ReplacedOp,
SdwaSel SrcSel_ = DWORD, bool Abs_ = false, bool Neg_ = false,
bool Sext_ = false)
: SDWAOperand(TargetOp, ReplacedOp),
SrcSel(SrcSel_), Abs(Abs_), Neg(Neg_), Sext(Sext_) {}
MachineInstr *potentialToConvert(const SIInstrInfo *TII) override;
bool convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) override;
SdwaSel getSrcSel() const { return SrcSel; }
bool getAbs() const { return Abs; }
bool getNeg() const { return Neg; }
bool getSext() const { return Sext; }
uint64_t getSrcMods(const SIInstrInfo *TII,
const MachineOperand *SrcOp) const;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void print(raw_ostream& OS) const override;
#endif
};
class SDWADstOperand : public SDWAOperand {
private:
SdwaSel DstSel;
DstUnused DstUn;
public:
SDWADstOperand(MachineOperand *TargetOp, MachineOperand *ReplacedOp,
SdwaSel DstSel_ = DWORD, DstUnused DstUn_ = UNUSED_PAD)
: SDWAOperand(TargetOp, ReplacedOp), DstSel(DstSel_), DstUn(DstUn_) {}
MachineInstr *potentialToConvert(const SIInstrInfo *TII) override;
bool convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) override;
SdwaSel getDstSel() const { return DstSel; }
DstUnused getDstUnused() const { return DstUn; }
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void print(raw_ostream& OS) const override;
#endif
};
class SDWADstPreserveOperand : public SDWADstOperand {
private:
MachineOperand *Preserve;
public:
SDWADstPreserveOperand(MachineOperand *TargetOp, MachineOperand *ReplacedOp,
MachineOperand *PreserveOp, SdwaSel DstSel_ = DWORD)
: SDWADstOperand(TargetOp, ReplacedOp, DstSel_, UNUSED_PRESERVE),
Preserve(PreserveOp) {}
bool convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) override;
MachineOperand *getPreservedOperand() const { return Preserve; }
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void print(raw_ostream& OS) const override;
#endif
};
} // end anonymous namespace
INITIALIZE_PASS(SIPeepholeSDWA, DEBUG_TYPE, "SI Peephole SDWA", false, false)
char SIPeepholeSDWA::ID = 0;
char &llvm::SIPeepholeSDWAID = SIPeepholeSDWA::ID;
FunctionPass *llvm::createSIPeepholeSDWAPass() {
return new SIPeepholeSDWA();
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
static raw_ostream& operator<<(raw_ostream &OS, SdwaSel Sel) {
switch(Sel) {
case BYTE_0: OS << "BYTE_0"; break;
case BYTE_1: OS << "BYTE_1"; break;
case BYTE_2: OS << "BYTE_2"; break;
case BYTE_3: OS << "BYTE_3"; break;
case WORD_0: OS << "WORD_0"; break;
case WORD_1: OS << "WORD_1"; break;
case DWORD: OS << "DWORD"; break;
}
return OS;
}
static raw_ostream& operator<<(raw_ostream &OS, const DstUnused &Un) {
switch(Un) {
case UNUSED_PAD: OS << "UNUSED_PAD"; break;
case UNUSED_SEXT: OS << "UNUSED_SEXT"; break;
case UNUSED_PRESERVE: OS << "UNUSED_PRESERVE"; break;
}
return OS;
}
static raw_ostream& operator<<(raw_ostream &OS, const SDWAOperand &Operand) {
Operand.print(OS);
return OS;
}
LLVM_DUMP_METHOD
void SDWASrcOperand::print(raw_ostream& OS) const {
OS << "SDWA src: " << *getTargetOperand()
<< " src_sel:" << getSrcSel()
<< " abs:" << getAbs() << " neg:" << getNeg()
<< " sext:" << getSext() << '\n';
}
LLVM_DUMP_METHOD
void SDWADstOperand::print(raw_ostream& OS) const {
OS << "SDWA dst: " << *getTargetOperand()
<< " dst_sel:" << getDstSel()
<< " dst_unused:" << getDstUnused() << '\n';
}
LLVM_DUMP_METHOD
void SDWADstPreserveOperand::print(raw_ostream& OS) const {
OS << "SDWA preserve dst: " << *getTargetOperand()
<< " dst_sel:" << getDstSel()
<< " preserve:" << *getPreservedOperand() << '\n';
}
#endif
static void copyRegOperand(MachineOperand &To, const MachineOperand &From) {
assert(To.isReg() && From.isReg());
To.setReg(From.getReg());
To.setSubReg(From.getSubReg());
To.setIsUndef(From.isUndef());
if (To.isUse()) {
To.setIsKill(From.isKill());
} else {
To.setIsDead(From.isDead());
}
}
static bool isSameReg(const MachineOperand &LHS, const MachineOperand &RHS) {
return LHS.isReg() &&
RHS.isReg() &&
LHS.getReg() == RHS.getReg() &&
LHS.getSubReg() == RHS.getSubReg();
}
static MachineOperand *findSingleRegUse(const MachineOperand *Reg,
const MachineRegisterInfo *MRI) {
if (!Reg->isReg() || !Reg->isDef())
return nullptr;
MachineOperand *ResMO = nullptr;
for (MachineOperand &UseMO : MRI->use_nodbg_operands(Reg->getReg())) {
// If there exist use of subreg of Reg then return nullptr
if (!isSameReg(UseMO, *Reg))
return nullptr;
// Check that there is only one instruction that uses Reg
if (!ResMO) {
ResMO = &UseMO;
} else if (ResMO->getParent() != UseMO.getParent()) {
return nullptr;
}
}
return ResMO;
}
static MachineOperand *findSingleRegDef(const MachineOperand *Reg,
const MachineRegisterInfo *MRI) {
if (!Reg->isReg())
return nullptr;
MachineInstr *DefInstr = MRI->getUniqueVRegDef(Reg->getReg());
if (!DefInstr)
return nullptr;
for (auto &DefMO : DefInstr->defs()) {
if (DefMO.isReg() && DefMO.getReg() == Reg->getReg())
return &DefMO;
}
// Ignore implicit defs.
return nullptr;
}
uint64_t SDWASrcOperand::getSrcMods(const SIInstrInfo *TII,
const MachineOperand *SrcOp) const {
uint64_t Mods = 0;
const auto *MI = SrcOp->getParent();
if (TII->getNamedOperand(*MI, AMDGPU::OpName::src0) == SrcOp) {
if (auto *Mod = TII->getNamedOperand(*MI, AMDGPU::OpName::src0_modifiers)) {
Mods = Mod->getImm();
}
} else if (TII->getNamedOperand(*MI, AMDGPU::OpName::src1) == SrcOp) {
if (auto *Mod = TII->getNamedOperand(*MI, AMDGPU::OpName::src1_modifiers)) {
Mods = Mod->getImm();
}
}
if (Abs || Neg) {
assert(!Sext &&
"Float and integer src modifiers can't be set simulteniously");
Mods |= Abs ? SISrcMods::ABS : 0;
Mods ^= Neg ? SISrcMods::NEG : 0;
} else if (Sext) {
Mods |= SISrcMods::SEXT;
}
return Mods;
}
MachineInstr *SDWASrcOperand::potentialToConvert(const SIInstrInfo *TII) {
// For SDWA src operand potential instruction is one that use register
// defined by parent instruction
MachineOperand *PotentialMO = findSingleRegUse(getReplacedOperand(), getMRI());
if (!PotentialMO)
return nullptr;
return PotentialMO->getParent();
}
bool SDWASrcOperand::convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) {
// Find operand in instruction that matches source operand and replace it with
// target operand. Set corresponding src_sel
bool IsPreserveSrc = false;
MachineOperand *Src = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
MachineOperand *SrcSel = TII->getNamedOperand(MI, AMDGPU::OpName::src0_sel);
MachineOperand *SrcMods =
TII->getNamedOperand(MI, AMDGPU::OpName::src0_modifiers);
assert(Src && (Src->isReg() || Src->isImm()));
if (!isSameReg(*Src, *getReplacedOperand())) {
// If this is not src0 then it could be src1
Src = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
SrcSel = TII->getNamedOperand(MI, AMDGPU::OpName::src1_sel);
SrcMods = TII->getNamedOperand(MI, AMDGPU::OpName::src1_modifiers);
if (!Src ||
!isSameReg(*Src, *getReplacedOperand())) {
// It's possible this Src is a tied operand for
// UNUSED_PRESERVE, in which case we can either
// abandon the peephole attempt, or if legal we can
// copy the target operand into the tied slot
// if the preserve operation will effectively cause the same
// result by overwriting the rest of the dst.
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
MachineOperand *DstUnused =
TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
if (Dst &&
DstUnused->getImm() == AMDGPU::SDWA::DstUnused::UNUSED_PRESERVE) {
// This will work if the tied src is acessing WORD_0, and the dst is
// writing WORD_1. Modifiers don't matter because all the bits that
// would be impacted are being overwritten by the dst.
// Any other case will not work.
SdwaSel DstSel = static_cast<SdwaSel>(
TII->getNamedImmOperand(MI, AMDGPU::OpName::dst_sel));
if (DstSel == AMDGPU::SDWA::SdwaSel::WORD_1 &&
getSrcSel() == AMDGPU::SDWA::SdwaSel::WORD_0) {
IsPreserveSrc = true;
auto DstIdx = AMDGPU::getNamedOperandIdx(MI.getOpcode(),
AMDGPU::OpName::vdst);
auto TiedIdx = MI.findTiedOperandIdx(DstIdx);
Src = &MI.getOperand(TiedIdx);
SrcSel = nullptr;
SrcMods = nullptr;
} else {
// Not legal to convert this src
return false;
}
}
}
assert(Src && Src->isReg());
if ((MI.getOpcode() == AMDGPU::V_MAC_F16_sdwa ||
MI.getOpcode() == AMDGPU::V_MAC_F32_sdwa) &&
!isSameReg(*Src, *getReplacedOperand())) {
// In case of v_mac_f16/32_sdwa this pass can try to apply src operand to
// src2. This is not allowed.
return false;
}
assert(isSameReg(*Src, *getReplacedOperand()) &&
(IsPreserveSrc || (SrcSel && SrcMods)));
}
copyRegOperand(*Src, *getTargetOperand());
if (!IsPreserveSrc) {
SrcSel->setImm(getSrcSel());
SrcMods->setImm(getSrcMods(TII, Src));
}
getTargetOperand()->setIsKill(false);
return true;
}
MachineInstr *SDWADstOperand::potentialToConvert(const SIInstrInfo *TII) {
// For SDWA dst operand potential instruction is one that defines register
// that this operand uses
MachineRegisterInfo *MRI = getMRI();
MachineInstr *ParentMI = getParentInst();
MachineOperand *PotentialMO = findSingleRegDef(getReplacedOperand(), MRI);
if (!PotentialMO)
return nullptr;
// Check that ParentMI is the only instruction that uses replaced register
for (MachineInstr &UseInst : MRI->use_nodbg_instructions(PotentialMO->getReg())) {
if (&UseInst != ParentMI)
return nullptr;
}
return PotentialMO->getParent();
}
bool SDWADstOperand::convertToSDWA(MachineInstr &MI, const SIInstrInfo *TII) {
// Replace vdst operand in MI with target operand. Set dst_sel and dst_unused
if ((MI.getOpcode() == AMDGPU::V_MAC_F16_sdwa ||
MI.getOpcode() == AMDGPU::V_MAC_F32_sdwa) &&
getDstSel() != AMDGPU::SDWA::DWORD) {
// v_mac_f16/32_sdwa allow dst_sel to be equal only to DWORD
return false;
}
MachineOperand *Operand = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
assert(Operand &&
Operand->isReg() &&
isSameReg(*Operand, *getReplacedOperand()));
copyRegOperand(*Operand, *getTargetOperand());
MachineOperand *DstSel= TII->getNamedOperand(MI, AMDGPU::OpName::dst_sel);
assert(DstSel);
DstSel->setImm(getDstSel());
MachineOperand *DstUnused= TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
assert(DstUnused);
DstUnused->setImm(getDstUnused());
// Remove original instruction because it would conflict with our new
// instruction by register definition
getParentInst()->eraseFromParent();
return true;
}
bool SDWADstPreserveOperand::convertToSDWA(MachineInstr &MI,
const SIInstrInfo *TII) {
// MI should be moved right before v_or_b32.
// For this we should clear all kill flags on uses of MI src-operands or else
// we can encounter problem with use of killed operand.
for (MachineOperand &MO : MI.uses()) {
if (!MO.isReg())
continue;
getMRI()->clearKillFlags(MO.getReg());
}
// Move MI before v_or_b32
auto MBB = MI.getParent();
MBB->remove(&MI);
MBB->insert(getParentInst(), &MI);
// Add Implicit use of preserved register
MachineInstrBuilder MIB(*MBB->getParent(), MI);
MIB.addReg(getPreservedOperand()->getReg(),
RegState::ImplicitKill,
getPreservedOperand()->getSubReg());
// Tie dst to implicit use
MI.tieOperands(AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::vdst),
MI.getNumOperands() - 1);
// Convert MI as any other SDWADstOperand and remove v_or_b32
return SDWADstOperand::convertToSDWA(MI, TII);
}
Optional<int64_t> SIPeepholeSDWA::foldToImm(const MachineOperand &Op) const {
if (Op.isImm()) {
return Op.getImm();
}
// If this is not immediate then it can be copy of immediate value, e.g.:
// %1 = S_MOV_B32 255;
if (Op.isReg()) {
for (const MachineOperand &Def : MRI->def_operands(Op.getReg())) {
if (!isSameReg(Op, Def))
continue;
const MachineInstr *DefInst = Def.getParent();
if (!TII->isFoldableCopy(*DefInst))
return None;
const MachineOperand &Copied = DefInst->getOperand(1);
if (!Copied.isImm())
return None;
return Copied.getImm();
}
}
return None;
}
std::unique_ptr<SDWAOperand>
SIPeepholeSDWA::matchSDWAOperand(MachineInstr &MI) {
unsigned Opcode = MI.getOpcode();
switch (Opcode) {
case AMDGPU::V_LSHRREV_B32_e32:
case AMDGPU::V_ASHRREV_I32_e32:
case AMDGPU::V_LSHLREV_B32_e32:
case AMDGPU::V_LSHRREV_B32_e64:
case AMDGPU::V_ASHRREV_I32_e64:
case AMDGPU::V_LSHLREV_B32_e64: {
// from: v_lshrrev_b32_e32 v1, 16/24, v0
// to SDWA src:v0 src_sel:WORD_1/BYTE_3
// from: v_ashrrev_i32_e32 v1, 16/24, v0
// to SDWA src:v0 src_sel:WORD_1/BYTE_3 sext:1
// from: v_lshlrev_b32_e32 v1, 16/24, v0
// to SDWA dst:v1 dst_sel:WORD_1/BYTE_3 dst_unused:UNUSED_PAD
MachineOperand *Src0 = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
auto Imm = foldToImm(*Src0);
if (!Imm)
break;
if (*Imm != 16 && *Imm != 24)
break;
MachineOperand *Src1 = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
if (TRI->isPhysicalRegister(Src1->getReg()) ||
TRI->isPhysicalRegister(Dst->getReg()))
break;
if (Opcode == AMDGPU::V_LSHLREV_B32_e32 ||
Opcode == AMDGPU::V_LSHLREV_B32_e64) {
return make_unique<SDWADstOperand>(
Dst, Src1, *Imm == 16 ? WORD_1 : BYTE_3, UNUSED_PAD);
} else {
return make_unique<SDWASrcOperand>(
Src1, Dst, *Imm == 16 ? WORD_1 : BYTE_3, false, false,
Opcode != AMDGPU::V_LSHRREV_B32_e32 &&
Opcode != AMDGPU::V_LSHRREV_B32_e64);
}
break;
}
case AMDGPU::V_LSHRREV_B16_e32:
case AMDGPU::V_ASHRREV_I16_e32:
case AMDGPU::V_LSHLREV_B16_e32:
case AMDGPU::V_LSHRREV_B16_e64:
case AMDGPU::V_ASHRREV_I16_e64:
case AMDGPU::V_LSHLREV_B16_e64: {
// from: v_lshrrev_b16_e32 v1, 8, v0
// to SDWA src:v0 src_sel:BYTE_1
// from: v_ashrrev_i16_e32 v1, 8, v0
// to SDWA src:v0 src_sel:BYTE_1 sext:1
// from: v_lshlrev_b16_e32 v1, 8, v0
// to SDWA dst:v1 dst_sel:BYTE_1 dst_unused:UNUSED_PAD
MachineOperand *Src0 = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
auto Imm = foldToImm(*Src0);
if (!Imm || *Imm != 8)
break;
MachineOperand *Src1 = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
if (TRI->isPhysicalRegister(Src1->getReg()) ||
TRI->isPhysicalRegister(Dst->getReg()))
break;
if (Opcode == AMDGPU::V_LSHLREV_B16_e32 ||
Opcode == AMDGPU::V_LSHLREV_B16_e64) {
return make_unique<SDWADstOperand>(Dst, Src1, BYTE_1, UNUSED_PAD);
} else {
return make_unique<SDWASrcOperand>(
Src1, Dst, BYTE_1, false, false,
Opcode != AMDGPU::V_LSHRREV_B16_e32 &&
Opcode != AMDGPU::V_LSHRREV_B16_e64);
}
break;
}
case AMDGPU::V_BFE_I32:
case AMDGPU::V_BFE_U32: {
// e.g.:
// from: v_bfe_u32 v1, v0, 8, 8
// to SDWA src:v0 src_sel:BYTE_1
// offset | width | src_sel
// ------------------------
// 0 | 8 | BYTE_0
// 0 | 16 | WORD_0
// 0 | 32 | DWORD ?
// 8 | 8 | BYTE_1
// 16 | 8 | BYTE_2
// 16 | 16 | WORD_1
// 24 | 8 | BYTE_3
MachineOperand *Src1 = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
auto Offset = foldToImm(*Src1);
if (!Offset)
break;
MachineOperand *Src2 = TII->getNamedOperand(MI, AMDGPU::OpName::src2);
auto Width = foldToImm(*Src2);
if (!Width)
break;
SdwaSel SrcSel = DWORD;
if (*Offset == 0 && *Width == 8)
SrcSel = BYTE_0;
else if (*Offset == 0 && *Width == 16)
SrcSel = WORD_0;
else if (*Offset == 0 && *Width == 32)
SrcSel = DWORD;
else if (*Offset == 8 && *Width == 8)
SrcSel = BYTE_1;
else if (*Offset == 16 && *Width == 8)
SrcSel = BYTE_2;
else if (*Offset == 16 && *Width == 16)
SrcSel = WORD_1;
else if (*Offset == 24 && *Width == 8)
SrcSel = BYTE_3;
else
break;
MachineOperand *Src0 = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
if (TRI->isPhysicalRegister(Src0->getReg()) ||
TRI->isPhysicalRegister(Dst->getReg()))
break;
return make_unique<SDWASrcOperand>(
Src0, Dst, SrcSel, false, false, Opcode != AMDGPU::V_BFE_U32);
}
case AMDGPU::V_AND_B32_e32:
case AMDGPU::V_AND_B32_e64: {
// e.g.:
// from: v_and_b32_e32 v1, 0x0000ffff/0x000000ff, v0
// to SDWA src:v0 src_sel:WORD_0/BYTE_0
MachineOperand *Src0 = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
MachineOperand *Src1 = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
auto ValSrc = Src1;
auto Imm = foldToImm(*Src0);
if (!Imm) {
Imm = foldToImm(*Src1);
ValSrc = Src0;
}
if (!Imm || (*Imm != 0x0000ffff && *Imm != 0x000000ff))
break;
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
if (TRI->isPhysicalRegister(ValSrc->getReg()) ||
TRI->isPhysicalRegister(Dst->getReg()))
break;
return make_unique<SDWASrcOperand>(
ValSrc, Dst, *Imm == 0x0000ffff ? WORD_0 : BYTE_0);
}
case AMDGPU::V_OR_B32_e32:
case AMDGPU::V_OR_B32_e64: {
// Patterns for dst_unused:UNUSED_PRESERVE.
// e.g., from:
// v_add_f16_sdwa v0, v1, v2 dst_sel:WORD_1 dst_unused:UNUSED_PAD
// src1_sel:WORD_1 src2_sel:WORD1
// v_add_f16_e32 v3, v1, v2
// v_or_b32_e32 v4, v0, v3
// to SDWA preserve dst:v4 dst_sel:WORD_1 dst_unused:UNUSED_PRESERVE preserve:v3
// Check if one of operands of v_or_b32 is SDWA instruction
using CheckRetType = Optional<std::pair<MachineOperand *, MachineOperand *>>;
auto CheckOROperandsForSDWA =
[&](const MachineOperand *Op1, const MachineOperand *Op2) -> CheckRetType {
if (!Op1 || !Op1->isReg() || !Op2 || !Op2->isReg())
return CheckRetType(None);
MachineOperand *Op1Def = findSingleRegDef(Op1, MRI);
if (!Op1Def)
return CheckRetType(None);
MachineInstr *Op1Inst = Op1Def->getParent();
if (!TII->isSDWA(*Op1Inst))
return CheckRetType(None);
MachineOperand *Op2Def = findSingleRegDef(Op2, MRI);
if (!Op2Def)
return CheckRetType(None);
return CheckRetType(std::make_pair(Op1Def, Op2Def));
};
MachineOperand *OrSDWA = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
MachineOperand *OrOther = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
assert(OrSDWA && OrOther);
auto Res = CheckOROperandsForSDWA(OrSDWA, OrOther);
if (!Res) {
OrSDWA = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
OrOther = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
assert(OrSDWA && OrOther);
Res = CheckOROperandsForSDWA(OrSDWA, OrOther);
if (!Res)
break;
}
MachineOperand *OrSDWADef = Res->first;
MachineOperand *OrOtherDef = Res->second;
assert(OrSDWADef && OrOtherDef);
MachineInstr *SDWAInst = OrSDWADef->getParent();
MachineInstr *OtherInst = OrOtherDef->getParent();
// Check that OtherInstr is actually bitwise compatible with SDWAInst = their
// destination patterns don't overlap. Compatible instruction can be either
// regular instruction with compatible bitness or SDWA instruction with
// correct dst_sel
// SDWAInst | OtherInst bitness / OtherInst dst_sel
// -----------------------------------------------------
// DWORD | no / no
// WORD_0 | no / BYTE_2/3, WORD_1
// WORD_1 | 8/16-bit instructions / BYTE_0/1, WORD_0
// BYTE_0 | no / BYTE_1/2/3, WORD_1
// BYTE_1 | 8-bit / BYTE_0/2/3, WORD_1
// BYTE_2 | 8/16-bit / BYTE_0/1/3. WORD_0
// BYTE_3 | 8/16/24-bit / BYTE_0/1/2, WORD_0
// E.g. if SDWAInst is v_add_f16_sdwa dst_sel:WORD_1 then v_add_f16 is OK
// but v_add_f32 is not.
// TODO: add support for non-SDWA instructions as OtherInst.
// For now this only works with SDWA instructions. For regular instructions
// there is no way to determine if the instruction writes only 8/16/24-bit
// out of full register size and all registers are at min 32-bit wide.
if (!TII->isSDWA(*OtherInst))
break;
SdwaSel DstSel = static_cast<SdwaSel>(
TII->getNamedImmOperand(*SDWAInst, AMDGPU::OpName::dst_sel));;
SdwaSel OtherDstSel = static_cast<SdwaSel>(
TII->getNamedImmOperand(*OtherInst, AMDGPU::OpName::dst_sel));
bool DstSelAgree = false;
switch (DstSel) {
case WORD_0: DstSelAgree = ((OtherDstSel == BYTE_2) ||
(OtherDstSel == BYTE_3) ||
(OtherDstSel == WORD_1));
break;
case WORD_1: DstSelAgree = ((OtherDstSel == BYTE_0) ||
(OtherDstSel == BYTE_1) ||
(OtherDstSel == WORD_0));
break;
case BYTE_0: DstSelAgree = ((OtherDstSel == BYTE_1) ||
(OtherDstSel == BYTE_2) ||
(OtherDstSel == BYTE_3) ||
(OtherDstSel == WORD_1));
break;
case BYTE_1: DstSelAgree = ((OtherDstSel == BYTE_0) ||
(OtherDstSel == BYTE_2) ||
(OtherDstSel == BYTE_3) ||
(OtherDstSel == WORD_1));
break;
case BYTE_2: DstSelAgree = ((OtherDstSel == BYTE_0) ||
(OtherDstSel == BYTE_1) ||
(OtherDstSel == BYTE_3) ||
(OtherDstSel == WORD_0));
break;
case BYTE_3: DstSelAgree = ((OtherDstSel == BYTE_0) ||
(OtherDstSel == BYTE_1) ||
(OtherDstSel == BYTE_2) ||
(OtherDstSel == WORD_0));
break;
default: DstSelAgree = false;
}
if (!DstSelAgree)
break;
// Also OtherInst dst_unused should be UNUSED_PAD
DstUnused OtherDstUnused = static_cast<DstUnused>(
TII->getNamedImmOperand(*OtherInst, AMDGPU::OpName::dst_unused));
if (OtherDstUnused != DstUnused::UNUSED_PAD)
break;
// Create DstPreserveOperand
MachineOperand *OrDst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
assert(OrDst && OrDst->isReg());
return make_unique<SDWADstPreserveOperand>(
OrDst, OrSDWADef, OrOtherDef, DstSel);
}
}
return std::unique_ptr<SDWAOperand>(nullptr);
}
void SIPeepholeSDWA::matchSDWAOperands(MachineBasicBlock &MBB) {
for (MachineInstr &MI : MBB) {
if (auto Operand = matchSDWAOperand(MI)) {
LLVM_DEBUG(dbgs() << "Match: " << MI << "To: " << *Operand << '\n');
SDWAOperands[&MI] = std::move(Operand);
++NumSDWAPatternsFound;
}
}
}
bool SIPeepholeSDWA::isConvertibleToSDWA(const MachineInstr &MI,
const GCNSubtarget &ST) const {
// Check if this is already an SDWA instruction
unsigned Opc = MI.getOpcode();
if (TII->isSDWA(Opc))
return true;
// Check if this instruction has opcode that supports SDWA
if (AMDGPU::getSDWAOp(Opc) == -1)
Opc = AMDGPU::getVOPe32(Opc);
if (AMDGPU::getSDWAOp(Opc) == -1)
return false;
if (!ST.hasSDWAOmod() && TII->hasModifiersSet(MI, AMDGPU::OpName::omod))
return false;
if (TII->isVOPC(Opc)) {
if (!ST.hasSDWASdst()) {
const MachineOperand *SDst = TII->getNamedOperand(MI, AMDGPU::OpName::sdst);
if (SDst && SDst->getReg() != AMDGPU::VCC)
return false;
}
if (!ST.hasSDWAOutModsVOPC() &&
(TII->hasModifiersSet(MI, AMDGPU::OpName::clamp) ||
TII->hasModifiersSet(MI, AMDGPU::OpName::omod)))
return false;
} else if (TII->getNamedOperand(MI, AMDGPU::OpName::sdst) ||
!TII->getNamedOperand(MI, AMDGPU::OpName::vdst)) {
return false;
}
if (!ST.hasSDWAMac() && (Opc == AMDGPU::V_MAC_F16_e32 ||
Opc == AMDGPU::V_MAC_F32_e32))
return false;
// FIXME: has SDWA but require handling of implicit VCC use
if (Opc == AMDGPU::V_CNDMASK_B32_e32)
return false;
return true;
}
bool SIPeepholeSDWA::convertToSDWA(MachineInstr &MI,
const SDWAOperandsVector &SDWAOperands) {
LLVM_DEBUG(dbgs() << "Convert instruction:" << MI);
// Convert to sdwa
int SDWAOpcode;
unsigned Opcode = MI.getOpcode();
if (TII->isSDWA(Opcode)) {
SDWAOpcode = Opcode;
} else {
SDWAOpcode = AMDGPU::getSDWAOp(Opcode);
if (SDWAOpcode == -1)
SDWAOpcode = AMDGPU::getSDWAOp(AMDGPU::getVOPe32(Opcode));
}
assert(SDWAOpcode != -1);
const MCInstrDesc &SDWADesc = TII->get(SDWAOpcode);
// Create SDWA version of instruction MI and initialize its operands
MachineInstrBuilder SDWAInst =
BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), SDWADesc);
// Copy dst, if it is present in original then should also be present in SDWA
MachineOperand *Dst = TII->getNamedOperand(MI, AMDGPU::OpName::vdst);
if (Dst) {
assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::vdst) != -1);
SDWAInst.add(*Dst);
} else if ((Dst = TII->getNamedOperand(MI, AMDGPU::OpName::sdst))) {
assert(Dst &&
AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::sdst) != -1);
SDWAInst.add(*Dst);
} else {
assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::sdst) != -1);
SDWAInst.addReg(AMDGPU::VCC, RegState::Define);
}
// Copy src0, initialize src0_modifiers. All sdwa instructions has src0 and
// src0_modifiers (except for v_nop_sdwa, but it can't get here)
MachineOperand *Src0 = TII->getNamedOperand(MI, AMDGPU::OpName::src0);
assert(
Src0 &&
AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src0) != -1 &&
AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src0_modifiers) != -1);
if (auto *Mod = TII->getNamedOperand(MI, AMDGPU::OpName::src0_modifiers))
SDWAInst.addImm(Mod->getImm());
else
SDWAInst.addImm(0);
SDWAInst.add(*Src0);
// Copy src1 if present, initialize src1_modifiers.
MachineOperand *Src1 = TII->getNamedOperand(MI, AMDGPU::OpName::src1);
if (Src1) {
assert(
AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src1) != -1 &&
AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src1_modifiers) != -1);
if (auto *Mod = TII->getNamedOperand(MI, AMDGPU::OpName::src1_modifiers))
SDWAInst.addImm(Mod->getImm());
else
SDWAInst.addImm(0);
SDWAInst.add(*Src1);
}
if (SDWAOpcode == AMDGPU::V_MAC_F16_sdwa ||
SDWAOpcode == AMDGPU::V_MAC_F32_sdwa) {
// v_mac_f16/32 has additional src2 operand tied to vdst
MachineOperand *Src2 = TII->getNamedOperand(MI, AMDGPU::OpName::src2);
assert(Src2);
SDWAInst.add(*Src2);
}
// Copy clamp if present, initialize otherwise
assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::clamp) != -1);
MachineOperand *Clamp = TII->getNamedOperand(MI, AMDGPU::OpName::clamp);
if (Clamp) {
SDWAInst.add(*Clamp);
} else {
SDWAInst.addImm(0);
}
// Copy omod if present, initialize otherwise if needed
if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::omod) != -1) {
MachineOperand *OMod = TII->getNamedOperand(MI, AMDGPU::OpName::omod);
if (OMod) {
SDWAInst.add(*OMod);
} else {
SDWAInst.addImm(0);
}
}
// Copy dst_sel if present, initialize otherwise if needed
if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_sel) != -1) {
MachineOperand *DstSel = TII->getNamedOperand(MI, AMDGPU::OpName::dst_sel);
if (DstSel) {
SDWAInst.add(*DstSel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
}
// Copy dst_unused if present, initialize otherwise if needed
if (AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::dst_unused) != -1) {
MachineOperand *DstUnused = TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
if (DstUnused) {
SDWAInst.add(*DstUnused);
} else {
SDWAInst.addImm(AMDGPU::SDWA::DstUnused::UNUSED_PAD);
}
}
// Copy src0_sel if present, initialize otherwise
assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src0_sel) != -1);
MachineOperand *Src0Sel = TII->getNamedOperand(MI, AMDGPU::OpName::src0_sel);
if (Src0Sel) {
SDWAInst.add(*Src0Sel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
// Copy src1_sel if present, initialize otherwise if needed
if (Src1) {
assert(AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::src1_sel) != -1);
MachineOperand *Src1Sel = TII->getNamedOperand(MI, AMDGPU::OpName::src1_sel);
if (Src1Sel) {
SDWAInst.add(*Src1Sel);
} else {
SDWAInst.addImm(AMDGPU::SDWA::SdwaSel::DWORD);
}
}
// Check for a preserved register that needs to be copied.
auto DstUnused = TII->getNamedOperand(MI, AMDGPU::OpName::dst_unused);
if (DstUnused &&
DstUnused->getImm() == AMDGPU::SDWA::DstUnused::UNUSED_PRESERVE) {
// We expect, if we are here, that the instruction was already in it's SDWA form,
// with a tied operand.
assert(Dst && Dst->isTied());
assert(Opcode == static_cast<unsigned int>(SDWAOpcode));
// We also expect a vdst, since sdst can't preserve.
auto PreserveDstIdx = AMDGPU::getNamedOperandIdx(SDWAOpcode, AMDGPU::OpName::vdst);
assert(PreserveDstIdx != -1);
auto TiedIdx = MI.findTiedOperandIdx(PreserveDstIdx);
auto Tied = MI.getOperand(TiedIdx);
SDWAInst.add(Tied);
SDWAInst->tieOperands(PreserveDstIdx, SDWAInst->getNumOperands() - 1);
}
// Apply all sdwa operand patterns.
bool Converted = false;
for (auto &Operand : SDWAOperands) {
LLVM_DEBUG(dbgs() << *SDWAInst << "\nOperand: " << *Operand);
// There should be no intesection between SDWA operands and potential MIs
// e.g.:
// v_and_b32 v0, 0xff, v1 -> src:v1 sel:BYTE_0
// v_and_b32 v2, 0xff, v0 -> src:v0 sel:BYTE_0
// v_add_u32 v3, v4, v2
//
// In that example it is possible that we would fold 2nd instruction into 3rd
// (v_add_u32_sdwa) and then try to fold 1st instruction into 2nd (that was
// already destroyed). So if SDWAOperand is also a potential MI then do not
// apply it.
if (PotentialMatches.count(Operand->getParentInst()) == 0)
Converted |= Operand->convertToSDWA(*SDWAInst, TII);
}
if (Converted) {
ConvertedInstructions.push_back(SDWAInst);
} else {
SDWAInst->eraseFromParent();
return false;
}
LLVM_DEBUG(dbgs() << "\nInto:" << *SDWAInst << '\n');
++NumSDWAInstructionsPeepholed;
MI.eraseFromParent();
return true;
}
// If an instruction was converted to SDWA it should not have immediates or SGPR
// operands (allowed one SGPR on GFX9). Copy its scalar operands into VGPRs.
void SIPeepholeSDWA::legalizeScalarOperands(MachineInstr &MI,
const GCNSubtarget &ST) const {
const MCInstrDesc &Desc = TII->get(MI.getOpcode());
unsigned ConstantBusCount = 0;
for (MachineOperand &Op : MI.explicit_uses()) {
if (!Op.isImm() && !(Op.isReg() && !TRI->isVGPR(*MRI, Op.getReg())))
continue;
unsigned I = MI.getOperandNo(&Op);
if (Desc.OpInfo[I].RegClass == -1 ||
!TRI->hasVGPRs(TRI->getRegClass(Desc.OpInfo[I].RegClass)))
continue;
if (ST.hasSDWAScalar() && ConstantBusCount == 0 && Op.isReg() &&
TRI->isSGPRReg(*MRI, Op.getReg())) {
++ConstantBusCount;
continue;
}
unsigned VGPR = MRI->createVirtualRegister(&AMDGPU::VGPR_32RegClass);
auto Copy = BuildMI(*MI.getParent(), MI.getIterator(), MI.getDebugLoc(),
TII->get(AMDGPU::V_MOV_B32_e32), VGPR);
if (Op.isImm())
Copy.addImm(Op.getImm());
else if (Op.isReg())
Copy.addReg(Op.getReg(), Op.isKill() ? RegState::Kill : 0,
Op.getSubReg());
Op.ChangeToRegister(VGPR, false);
}
}
bool SIPeepholeSDWA::runOnMachineFunction(MachineFunction &MF) {
const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>();
if (!ST.hasSDWA() || skipFunction(MF.getFunction()))
return false;
MRI = &MF.getRegInfo();
TRI = ST.getRegisterInfo();
TII = ST.getInstrInfo();
// Find all SDWA operands in MF.
bool Ret = false;
for (MachineBasicBlock &MBB : MF) {
bool Changed = false;
do {
matchSDWAOperands(MBB);
for (const auto &OperandPair : SDWAOperands) {
const auto &Operand = OperandPair.second;
MachineInstr *PotentialMI = Operand->potentialToConvert(TII);
if (PotentialMI && isConvertibleToSDWA(*PotentialMI, ST)) {
PotentialMatches[PotentialMI].push_back(Operand.get());
}
}
for (auto &PotentialPair : PotentialMatches) {
MachineInstr &PotentialMI = *PotentialPair.first;
convertToSDWA(PotentialMI, PotentialPair.second);
}
PotentialMatches.clear();
SDWAOperands.clear();
Changed = !ConvertedInstructions.empty();
if (Changed)
Ret = true;
while (!ConvertedInstructions.empty())
legalizeScalarOperands(*ConvertedInstructions.pop_back_val(), ST);
} while (Changed);
}
return Ret;
}