diff options
Diffstat (limited to 'llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCShuffler.cpp')
| -rw-r--r-- | llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCShuffler.cpp | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCShuffler.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCShuffler.cpp new file mode 100644 index 00000000000..1d38761e374 --- /dev/null +++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCShuffler.cpp @@ -0,0 +1,181 @@ +//===----- 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" + +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; +} + +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; +} |
