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//===----- HexagonMCShuffler.cpp - MC bundle shuffling --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements the shuffling of insns inside a bundle according to the
// packet formation rules of the Hexagon ISA.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "hexagon-shuffle"
#include "Hexagon.h"
#include "MCTargetDesc/HexagonMCInstrInfo.h"
#include "MCTargetDesc/HexagonMCShuffler.h"
#include "MCTargetDesc/HexagonMCTargetDesc.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static cl::opt<bool>
DisableShuffle("disable-hexagon-shuffle", cl::Hidden, cl::init(false),
cl::desc("Disable Hexagon instruction shuffling"));
void HexagonMCShuffler::init(MCInst &MCB) {
if (HexagonMCInstrInfo::isBundle(MCB)) {
MCInst const *Extender = nullptr;
// Copy the bundle for the shuffling.
for (const auto &I : HexagonMCInstrInfo::bundleInstructions(MCB)) {
assert(!HexagonMCInstrInfo::getDesc(MCII, *I.getInst()).isPseudo());
MCInst *MI = const_cast<MCInst *>(I.getInst());
if (!HexagonMCInstrInfo::isImmext(*MI)) {
append(MI, Extender, HexagonMCInstrInfo::getUnits(MCII, STI, *MI),
false);
Extender = nullptr;
} else
Extender = MI;
}
}
BundleFlags = MCB.getOperand(0).getImm();
}
void HexagonMCShuffler::init(MCInst &MCB, MCInst const *AddMI,
bool bInsertAtFront) {
if (HexagonMCInstrInfo::isBundle(MCB)) {
if (bInsertAtFront && AddMI)
append(AddMI, nullptr, HexagonMCInstrInfo::getUnits(MCII, STI, *AddMI),
false);
MCInst const *Extender = nullptr;
// Copy the bundle for the shuffling.
for (auto const &I : HexagonMCInstrInfo::bundleInstructions(MCB)) {
assert(!HexagonMCInstrInfo::getDesc(MCII, *I.getInst()).isPseudo());
MCInst *MI = const_cast<MCInst *>(I.getInst());
if (!HexagonMCInstrInfo::isImmext(*MI)) {
append(MI, Extender, HexagonMCInstrInfo::getUnits(MCII, STI, *MI),
false);
Extender = nullptr;
} else
Extender = MI;
}
if (!bInsertAtFront && AddMI)
append(AddMI, nullptr, HexagonMCInstrInfo::getUnits(MCII, STI, *AddMI),
false);
}
BundleFlags = MCB.getOperand(0).getImm();
}
void HexagonMCShuffler::copyTo(MCInst &MCB) {
MCB.clear();
MCB.addOperand(MCOperand::createImm(BundleFlags));
// Copy the results into the bundle.
for (HexagonShuffler::iterator I = begin(); I != end(); ++I) {
MCInst const *MI = I->getDesc();
MCInst const *Extender = I->getExtender();
if (Extender)
MCB.addOperand(MCOperand::createInst(Extender));
MCB.addOperand(MCOperand::createInst(MI));
}
}
bool HexagonMCShuffler::reshuffleTo(MCInst &MCB) {
if (shuffle()) {
// Copy the results into the bundle.
copyTo(MCB);
} else
DEBUG(MCB.dump());
return (!getError());
}
bool llvm::HexagonMCShuffle(MCInstrInfo const &MCII, MCSubtargetInfo const &STI,
MCInst &MCB) {
HexagonMCShuffler MCS(MCII, STI, MCB);
if (DisableShuffle)
// Ignore if user chose so.
return false;
if (!HexagonMCInstrInfo::bundleSize(MCB)) {
// There once was a bundle:
// BUNDLE %D2<imp-def>, %R4<imp-def>, %R5<imp-def>, %D7<imp-def>, ...
// * %D2<def> = IMPLICIT_DEF; flags:
// * %D7<def> = IMPLICIT_DEF; flags:
// After the IMPLICIT_DEFs were removed by the asm printer, the bundle
// became empty.
DEBUG(dbgs() << "Skipping empty bundle");
return false;
} else if (!HexagonMCInstrInfo::isBundle(MCB)) {
DEBUG(dbgs() << "Skipping stand-alone insn");
return false;
}
// Reorder the bundle and copy the result.
if (!MCS.reshuffleTo(MCB)) {
// Unless there is any error, which should not happen at this point.
unsigned shuffleError = MCS.getError();
switch (shuffleError) {
default:
llvm_unreachable("unknown error");
case HexagonShuffler::SHUFFLE_ERROR_INVALID:
llvm_unreachable("invalid packet");
case HexagonShuffler::SHUFFLE_ERROR_STORES:
llvm_unreachable("too many stores");
case HexagonShuffler::SHUFFLE_ERROR_LOADS:
llvm_unreachable("too many loads");
case HexagonShuffler::SHUFFLE_ERROR_BRANCHES:
llvm_unreachable("too many branches");
case HexagonShuffler::SHUFFLE_ERROR_NOSLOTS:
llvm_unreachable("no suitable slot");
case HexagonShuffler::SHUFFLE_ERROR_SLOTS:
llvm_unreachable("over-subscribed slots");
case HexagonShuffler::SHUFFLE_SUCCESS: // Single instruction case.
return true;
}
}
return true;
}
unsigned
llvm::HexagonMCShuffle(MCInstrInfo const &MCII, MCSubtargetInfo const &STI,
MCContext &Context, MCInst &MCB,
SmallVector<DuplexCandidate, 8> possibleDuplexes) {
if (DisableShuffle)
return HexagonShuffler::SHUFFLE_SUCCESS;
if (!HexagonMCInstrInfo::bundleSize(MCB)) {
// There once was a bundle:
// BUNDLE %D2<imp-def>, %R4<imp-def>, %R5<imp-def>, %D7<imp-def>, ...
// * %D2<def> = IMPLICIT_DEF; flags:
// * %D7<def> = IMPLICIT_DEF; flags:
// After the IMPLICIT_DEFs were removed by the asm printer, the bundle
// became empty.
DEBUG(dbgs() << "Skipping empty bundle");
return HexagonShuffler::SHUFFLE_SUCCESS;
} else if (!HexagonMCInstrInfo::isBundle(MCB)) {
DEBUG(dbgs() << "Skipping stand-alone insn");
return HexagonShuffler::SHUFFLE_SUCCESS;
}
bool doneShuffling = false;
unsigned shuffleError;
while (possibleDuplexes.size() > 0 && (!doneShuffling)) {
// case of Duplex Found
DuplexCandidate duplexToTry = possibleDuplexes.pop_back_val();
MCInst Attempt(MCB);
HexagonMCInstrInfo::replaceDuplex(Context, Attempt, duplexToTry);
HexagonMCShuffler MCS(MCII, STI, Attempt); // copy packet to the shuffler
if (MCS.size() == 1) { // case of one duplex
// copy the created duplex in the shuffler to the bundle
MCS.copyTo(MCB);
return HexagonShuffler::SHUFFLE_SUCCESS;
}
// try shuffle with this duplex
doneShuffling = MCS.reshuffleTo(MCB);
shuffleError = MCS.getError();
if (doneShuffling)
break;
}
if (doneShuffling == false) {
HexagonMCShuffler MCS(MCII, STI, MCB);
doneShuffling = MCS.reshuffleTo(MCB); // shuffle
shuffleError = MCS.getError();
}
if (!doneShuffling)
return shuffleError;
return HexagonShuffler::SHUFFLE_SUCCESS;
}
bool llvm::HexagonMCShuffle(MCInstrInfo const &MCII, MCSubtargetInfo const &STI,
MCInst &MCB, MCInst const *AddMI, int fixupCount) {
if (!HexagonMCInstrInfo::isBundle(MCB) || !AddMI)
return false;
// if fixups present, make sure we don't insert too many nops that would
// later prevent an extender from being inserted.
unsigned int bundleSize = HexagonMCInstrInfo::bundleSize(MCB);
if (bundleSize >= HEXAGON_PACKET_SIZE)
return false;
if (fixupCount >= 2) {
return false;
} else {
if (bundleSize == HEXAGON_PACKET_SIZE - 1 && fixupCount)
return false;
}
if (DisableShuffle)
return false;
HexagonMCShuffler MCS(MCII, STI, MCB, AddMI);
if (!MCS.reshuffleTo(MCB)) {
unsigned shuffleError = MCS.getError();
switch (shuffleError) {
default:
return false;
case HexagonShuffler::SHUFFLE_SUCCESS: // single instruction case
return true;
}
}
return true;
}
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