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//===- GCNCreateVOPD.cpp - Create VOPD 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
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Combine VALU pairs into VOPD instructions
/// Only works on wave32
/// Has register requirements, we reject creating VOPD if the requirements are
/// not met.
/// shouldCombineVOPD mutator in postRA machine scheduler puts candidate
/// instructions for VOPD back-to-back
///
//
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "GCNSubtarget.h"
#include "GCNVOPDUtils.h"
#include "SIInstrInfo.h"
#include "Utils/AMDGPUBaseInfo.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachinePassManager.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "gcn-create-vopd"
STATISTIC(NumVOPDCreated, "Number of VOPD Insts Created.");
using namespace llvm;
namespace {
class GCNCreateVOPD {
private:
class VOPDCombineInfo {
public:
VOPDCombineInfo() = default;
VOPDCombineInfo(MachineInstr *First, MachineInstr *Second,
bool VOPD3 = false)
: FirstMI(First), SecondMI(Second), IsVOPD3(VOPD3) {}
MachineInstr *FirstMI;
MachineInstr *SecondMI;
bool IsVOPD3;
};
public:
const GCNSubtarget *ST = nullptr;
bool doReplace(const SIInstrInfo *SII, VOPDCombineInfo &CI) {
auto *FirstMI = CI.FirstMI;
auto *SecondMI = CI.SecondMI;
unsigned Opc1 = FirstMI->getOpcode();
unsigned Opc2 = SecondMI->getOpcode();
unsigned EncodingFamily =
AMDGPU::getVOPDEncodingFamily(SII->getSubtarget());
int NewOpcode = AMDGPU::getVOPDFull(AMDGPU::getVOPDOpcode(Opc1, CI.IsVOPD3),
AMDGPU::getVOPDOpcode(Opc2, CI.IsVOPD3),
EncodingFamily, CI.IsVOPD3);
assert(NewOpcode != -1 &&
"Should have previously determined this as a possible VOPD\n");
auto VOPDInst = BuildMI(*FirstMI->getParent(), FirstMI,
FirstMI->getDebugLoc(), SII->get(NewOpcode))
.setMIFlags(FirstMI->getFlags() | SecondMI->getFlags());
namespace VOPD = AMDGPU::VOPD;
MachineInstr *MI[] = {FirstMI, SecondMI};
auto InstInfo =
AMDGPU::getVOPDInstInfo(FirstMI->getDesc(), SecondMI->getDesc());
for (auto CompIdx : VOPD::COMPONENTS) {
auto MCOprIdx = InstInfo[CompIdx].getIndexOfDstInMCOperands();
VOPDInst.add(MI[CompIdx]->getOperand(MCOprIdx));
}
const AMDGPU::OpName Mods[2][3] = {
{AMDGPU::OpName::src0X_modifiers, AMDGPU::OpName::vsrc1X_modifiers,
AMDGPU::OpName::vsrc2X_modifiers},
{AMDGPU::OpName::src0Y_modifiers, AMDGPU::OpName::vsrc1Y_modifiers,
AMDGPU::OpName::vsrc2Y_modifiers}};
const AMDGPU::OpName SrcMods[3] = {AMDGPU::OpName::src0_modifiers,
AMDGPU::OpName::src1_modifiers,
AMDGPU::OpName::src2_modifiers};
const unsigned VOPDOpc = VOPDInst->getOpcode();
for (auto CompIdx : VOPD::COMPONENTS) {
auto CompSrcOprNum = InstInfo[CompIdx].getCompSrcOperandsNum();
bool IsVOP3 = SII->isVOP3(*MI[CompIdx]);
for (unsigned CompSrcIdx = 0; CompSrcIdx < CompSrcOprNum; ++CompSrcIdx) {
if (AMDGPU::hasNamedOperand(VOPDOpc, Mods[CompIdx][CompSrcIdx])) {
const MachineOperand *Mod =
SII->getNamedOperand(*MI[CompIdx], SrcMods[CompSrcIdx]);
VOPDInst.addImm(Mod ? Mod->getImm() : 0);
}
auto MCOprIdx =
InstInfo[CompIdx].getIndexOfSrcInMCOperands(CompSrcIdx, IsVOP3);
VOPDInst.add(MI[CompIdx]->getOperand(MCOprIdx));
}
if (MI[CompIdx]->getOpcode() == AMDGPU::V_CNDMASK_B32_e32 && CI.IsVOPD3)
VOPDInst.addReg(AMDGPU::VCC_LO);
}
if (CI.IsVOPD3) {
if (unsigned BitOp2 = AMDGPU::getBitOp2(Opc2))
VOPDInst.addImm(BitOp2);
}
SII->fixImplicitOperands(*VOPDInst);
for (auto CompIdx : VOPD::COMPONENTS)
VOPDInst.copyImplicitOps(*MI[CompIdx]);
LLVM_DEBUG(dbgs() << "VOPD Fused: " << *VOPDInst << " from\tX: "
<< *CI.FirstMI << "\tY: " << *CI.SecondMI << "\n");
for (auto CompIdx : VOPD::COMPONENTS)
MI[CompIdx]->eraseFromParent();
++NumVOPDCreated;
return true;
}
bool run(MachineFunction &MF) {
ST = &MF.getSubtarget<GCNSubtarget>();
if (!AMDGPU::hasVOPD(*ST) || !ST->isWave32())
return false;
LLVM_DEBUG(dbgs() << "CreateVOPD Pass:\n");
const SIInstrInfo *SII = ST->getInstrInfo();
bool Changed = false;
unsigned EncodingFamily = AMDGPU::getVOPDEncodingFamily(*ST);
bool HasVOPD3 = ST->hasVOPD3();
SmallVector<VOPDCombineInfo> ReplaceCandidates;
for (auto &MBB : MF) {
auto MII = MBB.begin(), E = MBB.end();
while (MII != E) {
auto *FirstMI = &*MII;
MII = next_nodbg(MII, MBB.end());
if (MII == MBB.end())
break;
if (FirstMI->isDebugInstr())
continue;
auto *SecondMI = &*MII;
unsigned Opc = FirstMI->getOpcode();
unsigned Opc2 = SecondMI->getOpcode();
VOPDCombineInfo CI;
const auto checkVOPD = [&](bool VOPD3) -> bool {
llvm::AMDGPU::CanBeVOPD FirstCanBeVOPD =
AMDGPU::getCanBeVOPD(Opc, EncodingFamily, VOPD3);
llvm::AMDGPU::CanBeVOPD SecondCanBeVOPD =
AMDGPU::getCanBeVOPD(Opc2, EncodingFamily, VOPD3);
if (FirstCanBeVOPD.X && SecondCanBeVOPD.Y)
CI = VOPDCombineInfo(FirstMI, SecondMI, VOPD3);
else if (FirstCanBeVOPD.Y && SecondCanBeVOPD.X)
CI = VOPDCombineInfo(SecondMI, FirstMI, VOPD3);
else
return false;
// checkVOPDRegConstraints cares about program order, but doReplace
// cares about X-Y order in the constituted VOPD
return llvm::checkVOPDRegConstraints(*SII, *FirstMI, *SecondMI,
VOPD3);
};
if (checkVOPD(false) || (HasVOPD3 && checkVOPD(true))) {
ReplaceCandidates.push_back(CI);
++MII;
}
}
}
for (auto &CI : ReplaceCandidates) {
Changed |= doReplace(SII, CI);
}
return Changed;
}
};
class GCNCreateVOPDLegacy : public MachineFunctionPass {
public:
static char ID;
GCNCreateVOPDLegacy() : MachineFunctionPass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
StringRef getPassName() const override {
return "GCN Create VOPD Instructions";
}
bool runOnMachineFunction(MachineFunction &MF) override {
if (skipFunction(MF.getFunction()))
return false;
return GCNCreateVOPD().run(MF);
}
};
} // namespace
PreservedAnalyses
llvm::GCNCreateVOPDPass::run(MachineFunction &MF,
MachineFunctionAnalysisManager &AM) {
if (!GCNCreateVOPD().run(MF))
return PreservedAnalyses::all();
return getMachineFunctionPassPreservedAnalyses().preserveSet<CFGAnalyses>();
}
char GCNCreateVOPDLegacy::ID = 0;
char &llvm::GCNCreateVOPDID = GCNCreateVOPDLegacy::ID;
INITIALIZE_PASS(GCNCreateVOPDLegacy, DEBUG_TYPE, "GCN Create VOPD Instructions",
false, false)
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