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llvm-project/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonShuffler.cpp

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//===----- HexagonShuffler.cpp - Instruction 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 "HexagonShuffler.h"
#include "Hexagon.h"
#include "MCTargetDesc/HexagonBaseInfo.h"
#include "MCTargetDesc/HexagonMCInstrInfo.h"
#include "MCTargetDesc/HexagonMCTargetDesc.h"
#include "llvm/MC/MCContext.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <utility>
using namespace llvm;
namespace {
// Insn shuffling priority.
class HexagonBid {
// The priority is directly proportional to how restricted the insn is based
// on its flexibility to run on the available slots. So, the fewer slots it
// may run on, the higher its priority.
enum { MAX = 360360 }; // LCD of 1/2, 1/3, 1/4,... 1/15.
unsigned Bid;
public:
HexagonBid() : Bid(0) {}
HexagonBid(unsigned B) { Bid = B ? MAX / countPopulation(B) : 0; }
// Check if the insn priority is overflowed.
bool isSold() const { return (Bid >= MAX); }
HexagonBid &operator+=(const HexagonBid &B) {
Bid += B.Bid;
return *this;
}
};
// Slot shuffling allocation.
class HexagonUnitAuction {
HexagonBid Scores[HEXAGON_PACKET_SIZE];
// Mask indicating which slot is unavailable.
unsigned isSold : HEXAGON_PACKET_SIZE;
public:
HexagonUnitAuction(unsigned cs = 0) : isSold(cs){};
// Allocate slots.
bool bid(unsigned B) {
// Exclude already auctioned slots from the bid.
unsigned b = B & ~isSold;
if (b) {
for (unsigned i = 0; i < HEXAGON_PACKET_SIZE; ++i)
if (b & (1 << i)) {
// Request candidate slots.
Scores[i] += HexagonBid(b);
isSold |= Scores[i].isSold() << i;
}
return true;
} else
// Error if the desired slots are already full.
return false;
}
};
} // end anonymous namespace
unsigned HexagonResource::setWeight(unsigned s) {
const unsigned SlotWeight = 8;
const unsigned MaskWeight = SlotWeight - 1;
unsigned Units = getUnits();
unsigned Key = ((1u << s) & Units) != 0;
// Calculate relative weight of the insn for the given slot, weighing it the
// heavier the more restrictive the insn is and the lowest the slots that the
// insn may be executed in.
if (Key == 0 || Units == 0 || (SlotWeight * s >= 32))
return Weight = 0;
unsigned Ctpop = countPopulation(Units);
unsigned Cttz = countTrailingZeros(Units);
Weight = (1u << (SlotWeight * s)) * ((MaskWeight - Ctpop) << Cttz);
return Weight;
}
void HexagonCVIResource::SetupTUL(TypeUnitsAndLanes *TUL, StringRef CPU) {
(*TUL)[HexagonII::TypeCVI_VA] =
UnitsAndLanes(CVI_XLANE | CVI_SHIFT | CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VA_DV] = UnitsAndLanes(CVI_XLANE | CVI_MPY0, 2);
(*TUL)[HexagonII::TypeCVI_VX] = UnitsAndLanes(CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VX_LATE] = UnitsAndLanes(CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VX_DV] = UnitsAndLanes(CVI_MPY0, 2);
(*TUL)[HexagonII::TypeCVI_VP] = UnitsAndLanes(CVI_XLANE, 1);
(*TUL)[HexagonII::TypeCVI_VP_VS] = UnitsAndLanes(CVI_XLANE, 2);
(*TUL)[HexagonII::TypeCVI_VS] = UnitsAndLanes(CVI_SHIFT, 1);
(*TUL)[HexagonII::TypeCVI_VINLANESAT] =
(CPU == "hexagonv60")
? UnitsAndLanes(CVI_SHIFT, 1)
: UnitsAndLanes(CVI_XLANE | CVI_SHIFT | CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VM_LD] =
UnitsAndLanes(CVI_XLANE | CVI_SHIFT | CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VM_TMP_LD] = UnitsAndLanes(CVI_NONE, 0);
(*TUL)[HexagonII::TypeCVI_VM_VP_LDU] = UnitsAndLanes(CVI_XLANE, 1);
(*TUL)[HexagonII::TypeCVI_VM_ST] =
UnitsAndLanes(CVI_XLANE | CVI_SHIFT | CVI_MPY0 | CVI_MPY1, 1);
(*TUL)[HexagonII::TypeCVI_VM_NEW_ST] = UnitsAndLanes(CVI_NONE, 0);
(*TUL)[HexagonII::TypeCVI_VM_STU] = UnitsAndLanes(CVI_XLANE, 1);
(*TUL)[HexagonII::TypeCVI_HIST] = UnitsAndLanes(CVI_XLANE, 4);
}
HexagonCVIResource::HexagonCVIResource(TypeUnitsAndLanes *TUL,
MCInstrInfo const &MCII, unsigned s,
MCInst const *id)
: HexagonResource(s), TUL(TUL) {
unsigned T = HexagonMCInstrInfo::getType(MCII, *id);
if (TUL->count(T)) {
// For an HVX insn.
Valid = true;
setUnits((*TUL)[T].first);
setLanes((*TUL)[T].second);
setLoad(HexagonMCInstrInfo::getDesc(MCII, *id).mayLoad());
setStore(HexagonMCInstrInfo::getDesc(MCII, *id).mayStore());
} else {
// For core insns.
Valid = false;
setUnits(0);
setLanes(0);
setLoad(false);
setStore(false);
}
}
struct CVIUnits {
unsigned Units;
unsigned Lanes;
};
typedef SmallVector<struct CVIUnits, 8> HVXInstsT;
static unsigned makeAllBits(unsigned startBit, unsigned Lanes)
{
for (unsigned i = 1; i < Lanes; ++i)
startBit = (startBit << 1) | startBit;
return startBit;
}
static bool checkHVXPipes(const HVXInstsT &hvxInsts, unsigned startIdx,
unsigned usedUnits)
{
if (startIdx < hvxInsts.size()) {
if (!hvxInsts[startIdx].Units)
return checkHVXPipes(hvxInsts, startIdx + 1, usedUnits);
for (unsigned b = 0x1; b <= 0x8; b <<= 1) {
if ((hvxInsts[startIdx].Units & b) == 0)
continue;
unsigned allBits = makeAllBits(b, hvxInsts[startIdx].Lanes);
if ((allBits & usedUnits) == 0) {
if (checkHVXPipes(hvxInsts, startIdx + 1, usedUnits | allBits))
return true;
}
}
return false;
}
return true;
}
HexagonShuffler::HexagonShuffler(MCContext &Context, bool ReportErrors,
MCInstrInfo const &MCII,
MCSubtargetInfo const &STI)
: Context(Context), MCII(MCII), STI(STI), ReportErrors(ReportErrors) {
reset();
HexagonCVIResource::SetupTUL(&TUL, STI.getCPU());
}
void HexagonShuffler::reset() {
Packet.clear();
BundleFlags = 0;
}
void HexagonShuffler::append(MCInst const &ID, MCInst const *Extender,
unsigned S) {
HexagonInstr PI(&TUL, MCII, &ID, Extender, S);
Packet.push_back(PI);
}
static struct {
unsigned first;
unsigned second;
} jumpSlots[] = {{8, 4}, {8, 2}, {8, 1}, {4, 2}, {4, 1}, {2, 1}};
#define MAX_JUMP_SLOTS (sizeof(jumpSlots) / sizeof(jumpSlots[0]))
/// Check that the packet is legal and enforce relative insn order.
bool HexagonShuffler::check() {
// Descriptive slot masks.
const unsigned slotSingleLoad = 0x1, slotSingleStore = 0x1, slotOne = 0x2,
slotThree = 0x8, // slotFirstJump = 0x8,
slotFirstLoadStore = 0x2, slotLastLoadStore = 0x1;
// Highest slots for branches and stores used to keep their original order.
// unsigned slotJump = slotFirstJump;
unsigned slotLoadStore = slotFirstLoadStore;
// Number of branches, solo branches, indirect branches.
unsigned jumps = 0, jump1 = 0;
// Number of memory operations, loads, solo loads, stores, solo stores, single
// stores.
unsigned memory = 0, loads = 0, load0 = 0, stores = 0, store0 = 0, store1 = 0;
// Number of duplex insns
unsigned duplex = 0;
// Number of insns restricting other insns in slot #1 to A type.
unsigned onlyAin1 = 0;
// Number of insns restricting any insn in slot #1, except A2_nop.
unsigned onlyNo1 = 0;
unsigned pSlot3Cnt = 0;
unsigned nvstores = 0;
unsigned memops = 0;
unsigned deallocs = 0;
iterator slot3ISJ = end();
std::vector<iterator> foundBranches;
unsigned reservedSlots = 0;
// Collect information from the insns in the packet.
for (iterator ISJ = begin(); ISJ != end(); ++ISJ) {
MCInst const &ID = ISJ->getDesc();
if (HexagonMCInstrInfo::isSoloAin1(MCII, ID))
++onlyAin1;
if (HexagonMCInstrInfo::prefersSlot3(MCII, ID)) {
++pSlot3Cnt;
slot3ISJ = ISJ;
}
reservedSlots |= HexagonMCInstrInfo::getOtherReservedSlots(MCII, STI, ID);
if (HexagonMCInstrInfo::isCofMax1(MCII, ID))
++jump1;
switch (HexagonMCInstrInfo::getType(MCII, ID)) {
case HexagonII::TypeS_2op:
case HexagonII::TypeS_3op:
case HexagonII::TypeALU64:
break;
case HexagonII::TypeJ:
++jumps;
foundBranches.push_back(ISJ);
break;
case HexagonII::TypeCVI_VM_VP_LDU:
++onlyNo1;
case HexagonII::TypeCVI_VM_LD:
case HexagonII::TypeCVI_VM_TMP_LD:
case HexagonII::TypeLD:
++loads;
++memory;
if (ISJ->Core.getUnits() == slotSingleLoad ||
HexagonMCInstrInfo::getType(MCII, ID) == HexagonII::TypeCVI_VM_VP_LDU)
++load0;
if (HexagonMCInstrInfo::getDesc(MCII, ID).isReturn()) {
++deallocs, ++jumps, ++jump1; // DEALLOC_RETURN is of type LD.
foundBranches.push_back(ISJ);
}
break;
case HexagonII::TypeCVI_VM_STU:
++onlyNo1;
case HexagonII::TypeCVI_VM_ST:
case HexagonII::TypeCVI_VM_NEW_ST:
case HexagonII::TypeST:
++stores;
++memory;
if (ISJ->Core.getUnits() == slotSingleStore ||
HexagonMCInstrInfo::getType(MCII, ID) == HexagonII::TypeCVI_VM_STU)
++store0;
break;
case HexagonII::TypeV4LDST:
++loads;
++stores;
++store1;
++memops;
++memory;
break;
case HexagonII::TypeNCJ:
++memory; // NV insns are memory-like.
++jumps, ++jump1;
foundBranches.push_back(ISJ);
break;
case HexagonII::TypeV2LDST:
if (HexagonMCInstrInfo::getDesc(MCII, ID).mayLoad()) {
++loads;
++memory;
if (ISJ->Core.getUnits() == slotSingleLoad ||
HexagonMCInstrInfo::getType(MCII, ID) ==
HexagonII::TypeCVI_VM_VP_LDU)
++load0;
} else {
assert(HexagonMCInstrInfo::getDesc(MCII, ID).mayStore());
++memory;
++stores;
if (HexagonMCInstrInfo::isNewValue(MCII, ID))
++nvstores;
}
break;
case HexagonII::TypeCR:
// Legacy conditional branch predicated on a register.
case HexagonII::TypeCJ:
if (HexagonMCInstrInfo::getDesc(MCII, ID).isBranch()) {
++jumps;
foundBranches.push_back(ISJ);
}
break;
case HexagonII::TypeDUPLEX: {
++duplex;
MCInst const &Inst0 = *ID.getOperand(0).getInst();
MCInst const &Inst1 = *ID.getOperand(1).getInst();
if (HexagonMCInstrInfo::isCofMax1(MCII, Inst0))
++jump1;
if (HexagonMCInstrInfo::isCofMax1(MCII, Inst1))
++jump1;
if (HexagonMCInstrInfo::getDesc(MCII, Inst0).isBranch()) {
++jumps;
foundBranches.push_back(ISJ);
}
if (HexagonMCInstrInfo::getDesc(MCII, Inst1).isBranch()) {
++jumps;
foundBranches.push_back(ISJ);
}
if (HexagonMCInstrInfo::getDesc(MCII, Inst0).isReturn()) {
++deallocs, ++jumps, ++jump1; // DEALLOC_RETURN is of type LD.
foundBranches.push_back(ISJ);
}
if (HexagonMCInstrInfo::getDesc(MCII, Inst1).isReturn()) {
++deallocs, ++jumps, ++jump1; // DEALLOC_RETURN is of type LD.
foundBranches.push_back(ISJ);
}
break;
}
}
}
// Check if the packet is legal.
if ((load0 > 1 || store0 > 1) ||
(duplex > 1 || (duplex && memory))) {
reportError(llvm::Twine("invalid instruction packet"));
return false;
}
if (jump1 && jumps > 1) {
// Error if single branch with another branch.
reportError(llvm::Twine("too many branches in packet"));
return false;
}
if ((nvstores || memops) && stores > 1) {
reportError(llvm::Twine("slot 0 instruction does not allow slot 1 store"));
return false;
}
if (deallocs && stores) {
reportError(llvm::Twine("slot 0 instruction does not allow slot 1 store"));
return false;
}
// Modify packet accordingly.
// TODO: need to reserve slots #0 and #1 for duplex insns.
bool bOnlySlot3 = false;
for (iterator ISJ = begin(); ISJ != end(); ++ISJ) {
MCInst const &ID = ISJ->getDesc();
if (!ISJ->Core.getUnits()) {
// Error if insn may not be executed in any slot.
return false;
}
// Exclude from slot #1 any insn but A2_nop.
if (HexagonMCInstrInfo::getDesc(MCII, ID).getOpcode() != Hexagon::A2_nop)
if (onlyNo1)
ISJ->Core.setUnits(ISJ->Core.getUnits() & ~slotOne);
// Exclude from slot #1 any insn but A-type.
if (HexagonMCInstrInfo::getType(MCII, ID) != HexagonII::TypeALU32_2op &&
HexagonMCInstrInfo::getType(MCII, ID) != HexagonII::TypeALU32_3op &&
HexagonMCInstrInfo::getType(MCII, ID) != HexagonII::TypeALU32_ADDI)
if (onlyAin1)
ISJ->Core.setUnits(ISJ->Core.getUnits() & ~slotOne);
// A single load must use slot #0.
if (HexagonMCInstrInfo::getDesc(MCII, ID).mayLoad()) {
if (loads == 1 && loads == memory && memops == 0)
// Pin the load to slot #0.
ISJ->Core.setUnits(ISJ->Core.getUnits() & slotSingleLoad);
}
// A single store must use slot #0.
if (HexagonMCInstrInfo::getDesc(MCII, ID).mayStore()) {
if (!store0) {
if (stores == 1)
ISJ->Core.setUnits(ISJ->Core.getUnits() & slotSingleStore);
else if (stores > 1) {
if (slotLoadStore < slotLastLoadStore) {
// Error if no more slots available for stores.
reportError(
llvm::Twine("invalid instruction packet: too many stores"));
return false;
}
// Pin the store to the highest slot available to it.
ISJ->Core.setUnits(ISJ->Core.getUnits() & slotLoadStore);
// Update the next highest slot available to stores.
slotLoadStore >>= 1;
}
}
if (store1 && stores > 1) {
// Error if a single store with another store.
reportError(llvm::Twine("invalid instruction packet: too many stores"));
return false;
}
}
// flag if an instruction requires to be in slot 3
if (ISJ->Core.getUnits() == slotThree)
bOnlySlot3 = true;
if (!ISJ->Core.getUnits()) {
// Error if insn may not be executed in any slot.
reportError(llvm::Twine("invalid instruction packet: out of slots"));
return false;
}
}
// preserve branch order
bool validateSlots = true;
if (jumps > 1) {
if (foundBranches.size() > 2) {
reportError(llvm::Twine("too many branches in packet"));
return false;
}
// try all possible choices
for (unsigned int i = 0; i < MAX_JUMP_SLOTS; ++i) {
// validate first jump with this slot rule
if (!(jumpSlots[i].first & foundBranches[0]->Core.getUnits()))
continue;
// validate second jump with this slot rule
if (!(jumpSlots[i].second & foundBranches[1]->Core.getUnits()))
continue;
// both valid for this configuration, set new slot rules
PacketSave = Packet;
foundBranches[0]->Core.setUnits(jumpSlots[i].first);
foundBranches[1]->Core.setUnits(jumpSlots[i].second);
HexagonUnitAuction AuctionCore(reservedSlots);
std::sort(begin(), end(), HexagonInstr::lessCore);
// see if things ok with that instruction being pinned to slot "slotJump"
bool bFail = false;
for (iterator I = begin(); I != end() && bFail != true; ++I)
if (!AuctionCore.bid(I->Core.getUnits()))
bFail = true;
// if yes, great, if not then restore original slot mask
if (!bFail) {
validateSlots = false; // all good, no need to re-do auction
break;
} else
// restore original values
Packet = PacketSave;
}
if (validateSlots == true) {
reportError(llvm::Twine("invalid instruction packet: out of slots"));
return false;
}
}
if (jumps <= 1 && bOnlySlot3 == false && pSlot3Cnt == 1 &&
slot3ISJ != end()) {
validateSlots = true;
// save off slot mask of instruction marked with A_PREFER_SLOT3
// and then pin it to slot #3
unsigned saveUnits = slot3ISJ->Core.getUnits();
slot3ISJ->Core.setUnits(saveUnits & slotThree);
HexagonUnitAuction AuctionCore(reservedSlots);
std::sort(begin(), end(), HexagonInstr::lessCore);
// see if things ok with that instruction being pinned to slot #3
bool bFail = false;
for (iterator I = begin(); I != end() && bFail != true; ++I)
if (!AuctionCore.bid(I->Core.getUnits()))
bFail = true;
// if yes, great, if not then restore original slot mask
if (!bFail)
validateSlots = false; // all good, no need to re-do auction
else
for (iterator ISJ = begin(); ISJ != end(); ++ISJ) {
MCInst const &ID = ISJ->getDesc();
if (HexagonMCInstrInfo::prefersSlot3(MCII, ID))
ISJ->Core.setUnits(saveUnits);
}
}
// Check if any slot, core or CVI, is over-subscribed.
// Verify the core slot subscriptions.
if (validateSlots) {
HexagonUnitAuction AuctionCore(reservedSlots);
std::sort(begin(), end(), HexagonInstr::lessCore);
for (iterator I = begin(); I != end(); ++I)
if (!AuctionCore.bid(I->Core.getUnits())) {
reportError(llvm::Twine("invalid instruction packet: slot error"));
return false;
}
}
// Verify the CVI slot subscriptions.
std::sort(begin(), end(), HexagonInstr::lessCVI);
// create vector of hvx instructions to check
HVXInstsT hvxInsts;
hvxInsts.clear();
for (iterator I = begin(); I != end(); ++I) {
struct CVIUnits inst;
inst.Units = I->CVI.getUnits();
inst.Lanes = I->CVI.getLanes();
if (inst.Units == 0)
continue; // not an hvx inst or an hvx inst that doesn't uses any pipes
hvxInsts.push_back(inst);
}
// if there are any hvx instructions in this packet, check pipe usage
if (hvxInsts.size() > 0) {
unsigned startIdx, usedUnits;
startIdx = usedUnits = 0x0;
if (checkHVXPipes(hvxInsts, startIdx, usedUnits) == false) {
// too many pipes used to be valid
reportError(llvm::Twine("invalid instruction packet: slot error"));
return false;
}
}
return true;
}
bool HexagonShuffler::shuffle() {
if (size() > HEXAGON_PACKET_SIZE) {
// Ignore a packet with with more than what a packet can hold
// or with compound or duplex insns for now.
reportError(llvm::Twine("invalid instruction packet"));
return false;
}
// Check and prepare packet.
bool Ok = true;
if (size() > 1 && (Ok = check()))
// Reorder the handles for each slot.
for (unsigned nSlot = 0, emptySlots = 0; nSlot < HEXAGON_PACKET_SIZE;
++nSlot) {
iterator ISJ, ISK;
unsigned slotSkip, slotWeight;
// Prioritize the handles considering their restrictions.
for (ISJ = ISK = Packet.begin(), slotSkip = slotWeight = 0;
ISK != Packet.end(); ++ISK, ++slotSkip)
if (slotSkip < nSlot - emptySlots)
// Note which handle to begin at.
++ISJ;
else
// Calculate the weight of the slot.
slotWeight += ISK->Core.setWeight(HEXAGON_PACKET_SIZE - nSlot - 1);
if (slotWeight)
// Sort the packet, favoring source order,
// beginning after the previous slot.
std::sort(ISJ, Packet.end());
else
// Skip unused slot.
++emptySlots;
}
for (iterator ISJ = begin(); ISJ != end(); ++ISJ)
DEBUG(dbgs().write_hex(ISJ->Core.getUnits()); if (ISJ->CVI.isValid()) {
dbgs() << '/';
dbgs().write_hex(ISJ->CVI.getUnits()) << '|';
dbgs() << ISJ->CVI.getLanes();
} dbgs() << ':'
<< HexagonMCInstrInfo::getDesc(MCII, ISJ->getDesc()).getOpcode();
dbgs() << '\n');
DEBUG(dbgs() << '\n');
return Ok;
}
void HexagonShuffler::reportError(llvm::Twine const &Msg) {
if (ReportErrors)
Context.reportError(Loc, Msg);
}
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