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llvm-mirror/lib/Target/Hexagon/HexagonVLIWPacketizer.cpp

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//===----- HexagonPacketizer.cpp - vliw packetizer ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements a simple VLIW packetizer using DFA. The packetizer works on
// machine basic blocks. For each instruction I in BB, the packetizer consults
// the DFA to see if machine resources are available to execute I. If so, the
// packetizer checks if I depends on any instruction J in the current packet.
// If no dependency is found, I is added to current packet and machine resource
// is marked as taken. If any dependency is found, a target API call is made to
// prune the dependence.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/DFAPacketizer.h"
#include "Hexagon.h"
#include "HexagonMachineFunctionInfo.h"
#include "HexagonRegisterInfo.h"
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LatencyPriorityQueue.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionAnalysis.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/ScheduleDAG.h"
#include "llvm/CodeGen/ScheduleDAGInstrs.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <map>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "packets"
static cl::opt<bool> PacketizeVolatiles("hexagon-packetize-volatiles",
cl::ZeroOrMore, cl::Hidden, cl::init(true),
cl::desc("Allow non-solo packetization of volatile memory references"));
namespace llvm {
void initializeHexagonPacketizerPass(PassRegistry&);
}
namespace {
class HexagonPacketizer : public MachineFunctionPass {
public:
static char ID;
HexagonPacketizer() : MachineFunctionPass(ID) {
initializeHexagonPacketizerPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<MachineDominatorTree>();
AU.addRequired<MachineBranchProbabilityInfo>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
const char *getPassName() const override {
return "Hexagon Packetizer";
}
bool runOnMachineFunction(MachineFunction &Fn) override;
};
char HexagonPacketizer::ID = 0;
class HexagonPacketizerList : public VLIWPacketizerList {
private:
// Has the instruction been promoted to a dot-new instruction.
bool PromotedToDotNew;
// Has the instruction been glued to allocframe.
bool GlueAllocframeStore;
// Has the feeder instruction been glued to new value jump.
bool GlueToNewValueJump;
// Check if there is a dependence between some instruction already in this
// packet and this instruction.
bool Dependence;
// Only check for dependence if there are resources available to
// schedule this instruction.
bool FoundSequentialDependence;
/// \brief A handle to the branch probability pass.
const MachineBranchProbabilityInfo *MBPI;
// Track MIs with ignored dependece.
std::vector<MachineInstr*> IgnoreDepMIs;
public:
// Ctor.
HexagonPacketizerList(MachineFunction &MF, MachineLoopInfo &MLI,
const MachineBranchProbabilityInfo *MBPI);
// initPacketizerState - initialize some internal flags.
void initPacketizerState() override;
// ignorePseudoInstruction - Ignore bundling of pseudo instructions.
bool ignorePseudoInstruction(MachineInstr *MI,
MachineBasicBlock *MBB) override;
// isSoloInstruction - return true if instruction MI can not be packetized
// with any other instruction, which means that MI itself is a packet.
bool isSoloInstruction(MachineInstr *MI) override;
// isLegalToPacketizeTogether - Is it legal to packetize SUI and SUJ
// together.
bool isLegalToPacketizeTogether(SUnit *SUI, SUnit *SUJ) override;
// isLegalToPruneDependencies - Is it legal to prune dependece between SUI
// and SUJ.
bool isLegalToPruneDependencies(SUnit *SUI, SUnit *SUJ) override;
MachineBasicBlock::iterator addToPacket(MachineInstr *MI) override;
private:
bool IsCallDependent(MachineInstr* MI, SDep::Kind DepType, unsigned DepReg);
bool PromoteToDotNew(MachineInstr* MI, SDep::Kind DepType,
MachineBasicBlock::iterator &MII,
const TargetRegisterClass* RC);
bool CanPromoteToDotNew(MachineInstr *MI, SUnit *PacketSU, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit,
MachineBasicBlock::iterator &MII,
const TargetRegisterClass *RC);
bool
CanPromoteToNewValue(MachineInstr *MI, SUnit *PacketSU, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit,
MachineBasicBlock::iterator &MII);
bool CanPromoteToNewValueStore(
MachineInstr *MI, MachineInstr *PacketMI, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit);
bool DemoteToDotOld(MachineInstr *MI);
bool ArePredicatesComplements(
MachineInstr *MI1, MachineInstr *MI2,
const std::map<MachineInstr *, SUnit *> &MIToSUnit);
bool RestrictingDepExistInPacket(MachineInstr *, unsigned,
const std::map<MachineInstr *, SUnit *> &);
bool isNewifiable(MachineInstr* MI);
bool isCondInst(MachineInstr* MI);
bool tryAllocateResourcesForConstExt(MachineInstr* MI);
bool canReserveResourcesForConstExt(MachineInstr *MI);
void reserveResourcesForConstExt(MachineInstr* MI);
bool isNewValueInst(MachineInstr* MI);
};
}
INITIALIZE_PASS_BEGIN(HexagonPacketizer, "packets", "Hexagon Packetizer",
false, false)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_END(HexagonPacketizer, "packets", "Hexagon Packetizer",
false, false)
// HexagonPacketizerList Ctor.
HexagonPacketizerList::HexagonPacketizerList(
MachineFunction &MF, MachineLoopInfo &MLI,
const MachineBranchProbabilityInfo *MBPI)
: VLIWPacketizerList(MF, MLI, true) {
this->MBPI = MBPI;
}
bool HexagonPacketizer::runOnMachineFunction(MachineFunction &Fn) {
const TargetInstrInfo *TII = Fn.getSubtarget().getInstrInfo();
MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>();
const MachineBranchProbabilityInfo *MBPI =
&getAnalysis<MachineBranchProbabilityInfo>();
// Instantiate the packetizer.
HexagonPacketizerList Packetizer(Fn, MLI, MBPI);
// DFA state table should not be empty.
assert(Packetizer.getResourceTracker() && "Empty DFA table!");
//
// Loop over all basic blocks and remove KILL pseudo-instructions
// These instructions confuse the dependence analysis. Consider:
// D0 = ... (Insn 0)
// R0 = KILL R0, D0 (Insn 1)
// R0 = ... (Insn 2)
// Here, Insn 1 will result in the dependence graph not emitting an output
// dependence between Insn 0 and Insn 2. This can lead to incorrect
// packetization
//
for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
MBB != MBBe; ++MBB) {
MachineBasicBlock::iterator End = MBB->end();
MachineBasicBlock::iterator MI = MBB->begin();
while (MI != End) {
if (MI->isKill()) {
MachineBasicBlock::iterator DeleteMI = MI;
++MI;
MBB->erase(DeleteMI);
End = MBB->end();
continue;
}
++MI;
}
}
// Loop over all of the basic blocks.
for (MachineFunction::iterator MBB = Fn.begin(), MBBe = Fn.end();
MBB != MBBe; ++MBB) {
// Find scheduling regions and schedule / packetize each region.
unsigned RemainingCount = MBB->size();
for(MachineBasicBlock::iterator RegionEnd = MBB->end();
RegionEnd != MBB->begin();) {
// The next region starts above the previous region. Look backward in the
// instruction stream until we find the nearest boundary.
MachineBasicBlock::iterator I = RegionEnd;
for(;I != MBB->begin(); --I, --RemainingCount) {
if (TII->isSchedulingBoundary(std::prev(I), MBB, Fn))
break;
}
I = MBB->begin();
// Skip empty scheduling regions.
if (I == RegionEnd) {
RegionEnd = std::prev(RegionEnd);
--RemainingCount;
continue;
}
// Skip regions with one instruction.
if (I == std::prev(RegionEnd)) {
RegionEnd = std::prev(RegionEnd);
continue;
}
Packetizer.PacketizeMIs(MBB, I, RegionEnd);
RegionEnd = I;
}
}
return true;
}
static bool IsIndirectCall(MachineInstr* MI) {
return MI->getOpcode() == Hexagon::J2_callr;
}
// Reserve resources for constant extender. Trigure an assertion if
// reservation fail.
void HexagonPacketizerList::reserveResourcesForConstExt(MachineInstr* MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
MachineFunction *MF = MI->getParent()->getParent();
MachineInstr *PseudoMI = MF->CreateMachineInstr(QII->get(Hexagon::A4_ext),
MI->getDebugLoc());
if (ResourceTracker->canReserveResources(PseudoMI)) {
ResourceTracker->reserveResources(PseudoMI);
MI->getParent()->getParent()->DeleteMachineInstr(PseudoMI);
} else {
MI->getParent()->getParent()->DeleteMachineInstr(PseudoMI);
llvm_unreachable("can not reserve resources for constant extender.");
}
return;
}
bool HexagonPacketizerList::canReserveResourcesForConstExt(MachineInstr *MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
assert((QII->isExtended(MI) || QII->isConstExtended(MI)) &&
"Should only be called for constant extended instructions");
MachineFunction *MF = MI->getParent()->getParent();
MachineInstr *PseudoMI = MF->CreateMachineInstr(QII->get(Hexagon::A4_ext),
MI->getDebugLoc());
bool CanReserve = ResourceTracker->canReserveResources(PseudoMI);
MF->DeleteMachineInstr(PseudoMI);
return CanReserve;
}
// Allocate resources (i.e. 4 bytes) for constant extender. If succeed, return
// true, otherwise, return false.
bool HexagonPacketizerList::tryAllocateResourcesForConstExt(MachineInstr* MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
MachineFunction *MF = MI->getParent()->getParent();
MachineInstr *PseudoMI = MF->CreateMachineInstr(QII->get(Hexagon::A4_ext),
MI->getDebugLoc());
if (ResourceTracker->canReserveResources(PseudoMI)) {
ResourceTracker->reserveResources(PseudoMI);
MI->getParent()->getParent()->DeleteMachineInstr(PseudoMI);
return true;
} else {
MI->getParent()->getParent()->DeleteMachineInstr(PseudoMI);
return false;
}
}
bool HexagonPacketizerList::IsCallDependent(MachineInstr* MI,
SDep::Kind DepType,
unsigned DepReg) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
const HexagonRegisterInfo *QRI =
(const HexagonRegisterInfo *)MF.getSubtarget().getRegisterInfo();
// Check for lr dependence
if (DepReg == QRI->getRARegister()) {
return true;
}
if (QII->isDeallocRet(MI)) {
if (DepReg == QRI->getFrameRegister() ||
DepReg == QRI->getStackRegister())
return true;
}
// Check if this is a predicate dependence
const TargetRegisterClass* RC = QRI->getMinimalPhysRegClass(DepReg);
if (RC == &Hexagon::PredRegsRegClass) {
return true;
}
//
// Lastly check for an operand used in an indirect call
// If we had an attribute for checking if an instruction is an indirect call,
// then we could have avoided this relatively brittle implementation of
// IsIndirectCall()
//
// Assumes that the first operand of the CALLr is the function address
//
if (IsIndirectCall(MI) && (DepType == SDep::Data)) {
MachineOperand MO = MI->getOperand(0);
if (MO.isReg() && MO.isUse() && (MO.getReg() == DepReg)) {
return true;
}
}
return false;
}
static bool IsRegDependence(const SDep::Kind DepType) {
return (DepType == SDep::Data || DepType == SDep::Anti ||
DepType == SDep::Output);
}
static bool IsDirectJump(MachineInstr* MI) {
return (MI->getOpcode() == Hexagon::J2_jump);
}
static bool IsSchedBarrier(MachineInstr* MI) {
switch (MI->getOpcode()) {
case Hexagon::Y2_barrier:
return true;
}
return false;
}
static bool IsControlFlow(MachineInstr* MI) {
return (MI->getDesc().isTerminator() || MI->getDesc().isCall());
}
static bool IsLoopN(MachineInstr *MI) {
return (MI->getOpcode() == Hexagon::J2_loop0i ||
MI->getOpcode() == Hexagon::J2_loop0r);
}
/// DoesModifyCalleeSavedReg - Returns true if the instruction modifies a
/// callee-saved register.
static bool DoesModifyCalleeSavedReg(MachineInstr *MI,
const TargetRegisterInfo *TRI) {
for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(); *CSR; ++CSR) {
unsigned CalleeSavedReg = *CSR;
if (MI->modifiesRegister(CalleeSavedReg, TRI))
return true;
}
return false;
}
// Returns true if an instruction can be promoted to .new predicate
// or new-value store.
bool HexagonPacketizerList::isNewifiable(MachineInstr* MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
if ( isCondInst(MI) || QII->mayBeNewStore(MI))
return true;
else
return false;
}
bool HexagonPacketizerList::isCondInst (MachineInstr* MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
const MCInstrDesc& TID = MI->getDesc();
// bug 5670: until that is fixed,
// this portion is disabled.
if ( TID.isConditionalBranch() // && !IsRegisterJump(MI)) ||
|| QII->isConditionalTransfer(MI)
|| QII->isConditionalALU32(MI)
|| QII->isConditionalLoad(MI)
|| QII->isConditionalStore(MI)) {
return true;
}
return false;
}
// Promote an instructiont to its .new form.
// At this time, we have already made a call to CanPromoteToDotNew
// and made sure that it can *indeed* be promoted.
bool HexagonPacketizerList::PromoteToDotNew(MachineInstr* MI,
SDep::Kind DepType, MachineBasicBlock::iterator &MII,
const TargetRegisterClass* RC) {
assert (DepType == SDep::Data);
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
int NewOpcode;
if (RC == &Hexagon::PredRegsRegClass)
NewOpcode = QII->GetDotNewPredOp(MI, MBPI);
else
NewOpcode = QII->GetDotNewOp(MI);
MI->setDesc(QII->get(NewOpcode));
return true;
}
bool HexagonPacketizerList::DemoteToDotOld(MachineInstr* MI) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
int NewOpcode = QII->GetDotOldOp(MI->getOpcode());
MI->setDesc(QII->get(NewOpcode));
return true;
}
enum PredicateKind {
PK_False,
PK_True,
PK_Unknown
};
/// Returns true if an instruction is predicated on p0 and false if it's
/// predicated on !p0.
static PredicateKind getPredicateSense(MachineInstr* MI,
const HexagonInstrInfo *QII) {
if (!QII->isPredicated(MI))
return PK_Unknown;
if (QII->isPredicatedTrue(MI))
return PK_True;
return PK_False;
}
static MachineOperand& GetPostIncrementOperand(MachineInstr *MI,
const HexagonInstrInfo *QII) {
assert(QII->isPostIncrement(MI) && "Not a post increment operation.");
#ifndef NDEBUG
// Post Increment means duplicates. Use dense map to find duplicates in the
// list. Caution: Densemap initializes with the minimum of 64 buckets,
// whereas there are at most 5 operands in the post increment.
DenseMap<unsigned, unsigned> DefRegsSet;
for(unsigned opNum = 0; opNum < MI->getNumOperands(); opNum++)
if (MI->getOperand(opNum).isReg() &&
MI->getOperand(opNum).isDef()) {
DefRegsSet[MI->getOperand(opNum).getReg()] = 1;
}
for(unsigned opNum = 0; opNum < MI->getNumOperands(); opNum++)
if (MI->getOperand(opNum).isReg() &&
MI->getOperand(opNum).isUse()) {
if (DefRegsSet[MI->getOperand(opNum).getReg()]) {
return MI->getOperand(opNum);
}
}
#else
if (MI->getDesc().mayLoad()) {
// The 2nd operand is always the post increment operand in load.
assert(MI->getOperand(1).isReg() &&
"Post increment operand has be to a register.");
return (MI->getOperand(1));
}
if (MI->getDesc().mayStore()) {
// The 1st operand is always the post increment operand in store.
assert(MI->getOperand(0).isReg() &&
"Post increment operand has be to a register.");
return (MI->getOperand(0));
}
#endif
// we should never come here.
llvm_unreachable("mayLoad or mayStore not set for Post Increment operation");
}
// get the value being stored
static MachineOperand& GetStoreValueOperand(MachineInstr *MI) {
// value being stored is always the last operand.
return (MI->getOperand(MI->getNumOperands()-1));
}
// can be new value store?
// Following restrictions are to be respected in convert a store into
// a new value store.
// 1. If an instruction uses auto-increment, its address register cannot
// be a new-value register. Arch Spec 5.4.2.1
// 2. If an instruction uses absolute-set addressing mode,
// its address register cannot be a new-value register.
// Arch Spec 5.4.2.1.TODO: This is not enabled as
// as absolute-set address mode patters are not implemented.
// 3. If an instruction produces a 64-bit result, its registers cannot be used
// as new-value registers. Arch Spec 5.4.2.2.
// 4. If the instruction that sets a new-value register is conditional, then
// the instruction that uses the new-value register must also be conditional,
// and both must always have their predicates evaluate identically.
// Arch Spec 5.4.2.3.
// 5. There is an implied restriction of a packet can not have another store,
// if there is a new value store in the packet. Corollary, if there is
// already a store in a packet, there can not be a new value store.
// Arch Spec: 3.4.4.2
bool HexagonPacketizerList::CanPromoteToNewValueStore(
MachineInstr *MI, MachineInstr *PacketMI, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
// Make sure we are looking at the store, that can be promoted.
if (!QII->mayBeNewStore(MI))
return false;
// Make sure there is dependency and can be new value'ed
if (GetStoreValueOperand(MI).isReg() &&
GetStoreValueOperand(MI).getReg() != DepReg)
return false;
const HexagonRegisterInfo *QRI =
(const HexagonRegisterInfo *)MF.getSubtarget().getRegisterInfo();
const MCInstrDesc& MCID = PacketMI->getDesc();
// first operand is always the result
const TargetRegisterClass* PacketRC = QII->getRegClass(MCID, 0, QRI, MF);
// if there is already an store in the packet, no can do new value store
// Arch Spec 3.4.4.2.
for (std::vector<MachineInstr*>::iterator VI = CurrentPacketMIs.begin(),
VE = CurrentPacketMIs.end();
(VI != VE); ++VI) {
SUnit *PacketSU = MIToSUnit.find(*VI)->second;
if (PacketSU->getInstr()->getDesc().mayStore() ||
// if we have mayStore = 1 set on ALLOCFRAME and DEALLOCFRAME,
// then we don't need this
PacketSU->getInstr()->getOpcode() == Hexagon::S2_allocframe ||
PacketSU->getInstr()->getOpcode() == Hexagon::L2_deallocframe)
return false;
}
if (PacketRC == &Hexagon::DoubleRegsRegClass) {
// new value store constraint: double regs can not feed into new value store
// arch spec section: 5.4.2.2
return false;
}
// Make sure it's NOT the post increment register that we are going to
// new value.
if (QII->isPostIncrement(MI) &&
MI->getDesc().mayStore() &&
GetPostIncrementOperand(MI, QII).getReg() == DepReg) {
return false;
}
if (QII->isPostIncrement(PacketMI) &&
PacketMI->getDesc().mayLoad() &&
GetPostIncrementOperand(PacketMI, QII).getReg() == DepReg) {
// if source is post_inc, or absolute-set addressing,
// it can not feed into new value store
// r3 = memw(r2++#4)
// memw(r30 + #-1404) = r2.new -> can not be new value store
// arch spec section: 5.4.2.1
return false;
}
// If the source that feeds the store is predicated, new value store must
// also be predicated.
if (QII->isPredicated(PacketMI)) {
if (!QII->isPredicated(MI))
return false;
// Check to make sure that they both will have their predicates
// evaluate identically
unsigned predRegNumSrc = 0;
unsigned predRegNumDst = 0;
const TargetRegisterClass* predRegClass = nullptr;
// Get predicate register used in the source instruction
for(unsigned opNum = 0; opNum < PacketMI->getNumOperands(); opNum++) {
if ( PacketMI->getOperand(opNum).isReg())
predRegNumSrc = PacketMI->getOperand(opNum).getReg();
predRegClass = QRI->getMinimalPhysRegClass(predRegNumSrc);
if (predRegClass == &Hexagon::PredRegsRegClass) {
break;
}
}
assert ((predRegClass == &Hexagon::PredRegsRegClass ) &&
("predicate register not found in a predicated PacketMI instruction"));
// Get predicate register used in new-value store instruction
for(unsigned opNum = 0; opNum < MI->getNumOperands(); opNum++) {
if ( MI->getOperand(opNum).isReg())
predRegNumDst = MI->getOperand(opNum).getReg();
predRegClass = QRI->getMinimalPhysRegClass(predRegNumDst);
if (predRegClass == &Hexagon::PredRegsRegClass) {
break;
}
}
assert ((predRegClass == &Hexagon::PredRegsRegClass ) &&
("predicate register not found in a predicated MI instruction"));
// New-value register producer and user (store) need to satisfy these
// constraints:
// 1) Both instructions should be predicated on the same register.
// 2) If producer of the new-value register is .new predicated then store
// should also be .new predicated and if producer is not .new predicated
// then store should not be .new predicated.
// 3) Both new-value register producer and user should have same predicate
// sense, i.e, either both should be negated or both should be none negated.
if (( predRegNumDst != predRegNumSrc) ||
QII->isDotNewInst(PacketMI) != QII->isDotNewInst(MI) ||
getPredicateSense(MI, QII) != getPredicateSense(PacketMI, QII)) {
return false;
}
}
// Make sure that other than the new-value register no other store instruction
// register has been modified in the same packet. Predicate registers can be
// modified by they should not be modified between the producer and the store
// instruction as it will make them both conditional on different values.
// We already know this to be true for all the instructions before and
// including PacketMI. Howerver, we need to perform the check for the
// remaining instructions in the packet.
std::vector<MachineInstr*>::iterator VI;
std::vector<MachineInstr*>::iterator VE;
unsigned StartCheck = 0;
for (VI=CurrentPacketMIs.begin(), VE = CurrentPacketMIs.end();
(VI != VE); ++VI) {
SUnit *TempSU = MIToSUnit.find(*VI)->second;
MachineInstr* TempMI = TempSU->getInstr();
// Following condition is true for all the instructions until PacketMI is
// reached (StartCheck is set to 0 before the for loop).
// StartCheck flag is 1 for all the instructions after PacketMI.
if (TempMI != PacketMI && !StartCheck) // start processing only after
continue; // encountering PacketMI
StartCheck = 1;
if (TempMI == PacketMI) // We don't want to check PacketMI for dependence
continue;
for(unsigned opNum = 0; opNum < MI->getNumOperands(); opNum++) {
if (MI->getOperand(opNum).isReg() &&
TempSU->getInstr()->modifiesRegister(MI->getOperand(opNum).getReg(),
QRI))
return false;
}
}
// Make sure that for non-POST_INC stores:
// 1. The only use of reg is DepReg and no other registers.
// This handles V4 base+index registers.
// The following store can not be dot new.
// Eg. r0 = add(r0, #3)a
// memw(r1+r0<<#2) = r0
if (!QII->isPostIncrement(MI) &&
GetStoreValueOperand(MI).isReg() &&
GetStoreValueOperand(MI).getReg() == DepReg) {
for(unsigned opNum = 0; opNum < MI->getNumOperands()-1; opNum++) {
if (MI->getOperand(opNum).isReg() &&
MI->getOperand(opNum).getReg() == DepReg) {
return false;
}
}
// 2. If data definition is because of implicit definition of the register,
// do not newify the store. Eg.
// %R9<def> = ZXTH %R12, %D6<imp-use>, %R12<imp-def>
// STrih_indexed %R8, 2, %R12<kill>; mem:ST2[%scevgep343]
for(unsigned opNum = 0; opNum < PacketMI->getNumOperands(); opNum++) {
if (PacketMI->getOperand(opNum).isReg() &&
PacketMI->getOperand(opNum).getReg() == DepReg &&
PacketMI->getOperand(opNum).isDef() &&
PacketMI->getOperand(opNum).isImplicit()) {
return false;
}
}
}
// Can be dot new store.
return true;
}
// can this MI to promoted to either
// new value store or new value jump
bool HexagonPacketizerList::CanPromoteToNewValue(
MachineInstr *MI, SUnit *PacketSU, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit,
MachineBasicBlock::iterator &MII) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
const HexagonRegisterInfo *QRI =
(const HexagonRegisterInfo *)MF.getSubtarget().getRegisterInfo();
if (!QRI->Subtarget.hasV4TOps() ||
!QII->mayBeNewStore(MI))
return false;
MachineInstr *PacketMI = PacketSU->getInstr();
// Check to see the store can be new value'ed.
if (CanPromoteToNewValueStore(MI, PacketMI, DepReg, MIToSUnit))
return true;
// Check to see the compare/jump can be new value'ed.
// This is done as a pass on its own. Don't need to check it here.
return false;
}
// Check to see if an instruction can be dot new
// There are three kinds.
// 1. dot new on predicate - V2/V3/V4
// 2. dot new on stores NV/ST - V4
// 3. dot new on jump NV/J - V4 -- This is generated in a pass.
bool HexagonPacketizerList::CanPromoteToDotNew(
MachineInstr *MI, SUnit *PacketSU, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit,
MachineBasicBlock::iterator &MII, const TargetRegisterClass *RC) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
// Already a dot new instruction.
if (QII->isDotNewInst(MI) && !QII->mayBeNewStore(MI))
return false;
if (!isNewifiable(MI))
return false;
// predicate .new
if (RC == &Hexagon::PredRegsRegClass && isCondInst(MI))
return true;
else if (RC != &Hexagon::PredRegsRegClass &&
!QII->mayBeNewStore(MI)) // MI is not a new-value store
return false;
else {
// Create a dot new machine instruction to see if resources can be
// allocated. If not, bail out now.
int NewOpcode = QII->GetDotNewOp(MI);
const MCInstrDesc &desc = QII->get(NewOpcode);
DebugLoc dl;
MachineInstr *NewMI =
MI->getParent()->getParent()->CreateMachineInstr(desc, dl);
bool ResourcesAvailable = ResourceTracker->canReserveResources(NewMI);
MI->getParent()->getParent()->DeleteMachineInstr(NewMI);
if (!ResourcesAvailable)
return false;
// new value store only
// new new value jump generated as a passes
if (!CanPromoteToNewValue(MI, PacketSU, DepReg, MIToSUnit, MII)) {
return false;
}
}
return true;
}
// Go through the packet instructions and search for anti dependency
// between them and DepReg from MI
// Consider this case:
// Trying to add
// a) %R1<def> = TFRI_cdNotPt %P3, 2
// to this packet:
// {
// b) %P0<def> = OR_pp %P3<kill>, %P0<kill>
// c) %P3<def> = TFR_PdRs %R23
// d) %R1<def> = TFRI_cdnPt %P3, 4
// }
// The P3 from a) and d) will be complements after
// a)'s P3 is converted to .new form
// Anti Dep between c) and b) is irrelevant for this case
bool HexagonPacketizerList::RestrictingDepExistInPacket(
MachineInstr *MI, unsigned DepReg,
const std::map<MachineInstr *, SUnit *> &MIToSUnit) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
SUnit *PacketSUDep = MIToSUnit.find(MI)->second;
for (std::vector<MachineInstr*>::iterator VIN = CurrentPacketMIs.begin(),
VEN = CurrentPacketMIs.end(); (VIN != VEN); ++VIN) {
// We only care for dependencies to predicated instructions
if(!QII->isPredicated(*VIN)) continue;
// Scheduling Unit for current insn in the packet
SUnit *PacketSU = MIToSUnit.find(*VIN)->second;
// Look at dependencies between current members of the packet
// and predicate defining instruction MI.
// Make sure that dependency is on the exact register
// we care about.
if (PacketSU->isSucc(PacketSUDep)) {
for (unsigned i = 0; i < PacketSU->Succs.size(); ++i) {
if ((PacketSU->Succs[i].getSUnit() == PacketSUDep) &&
(PacketSU->Succs[i].getKind() == SDep::Anti) &&
(PacketSU->Succs[i].getReg() == DepReg)) {
return true;
}
}
}
}
return false;
}
/// Gets the predicate register of a predicated instruction.
static unsigned getPredicatedRegister(MachineInstr *MI,
const HexagonInstrInfo *QII) {
/// We use the following rule: The first predicate register that is a use is
/// the predicate register of a predicated instruction.
assert(QII->isPredicated(MI) && "Must be predicated instruction");
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
MachineOperand &Op = *OI;
if (Op.isReg() && Op.getReg() && Op.isUse() &&
Hexagon::PredRegsRegClass.contains(Op.getReg()))
return Op.getReg();
}
llvm_unreachable("Unknown instruction operand layout");
return 0;
}
// Given two predicated instructions, this function detects whether
// the predicates are complements
bool HexagonPacketizerList::ArePredicatesComplements(
MachineInstr *MI1, MachineInstr *MI2,
const std::map<MachineInstr *, SUnit *> &MIToSUnit) {
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
// If we don't know the predicate sense of the instructions bail out early, we
// need it later.
if (getPredicateSense(MI1, QII) == PK_Unknown ||
getPredicateSense(MI2, QII) == PK_Unknown)
return false;
// Scheduling unit for candidate
SUnit *SU = MIToSUnit.find(MI1)->second;
// One corner case deals with the following scenario:
// Trying to add
// a) %R24<def> = TFR_cPt %P0, %R25
// to this packet:
//
// {
// b) %R25<def> = TFR_cNotPt %P0, %R24
// c) %P0<def> = CMPEQri %R26, 1
// }
//
// On general check a) and b) are complements, but
// presence of c) will convert a) to .new form, and
// then it is not a complement
// We attempt to detect it by analyzing existing
// dependencies in the packet
// Analyze relationships between all existing members of the packet.
// Look for Anti dependecy on the same predicate reg
// as used in the candidate
for (std::vector<MachineInstr*>::iterator VIN = CurrentPacketMIs.begin(),
VEN = CurrentPacketMIs.end(); (VIN != VEN); ++VIN) {
// Scheduling Unit for current insn in the packet
SUnit *PacketSU = MIToSUnit.find(*VIN)->second;
// If this instruction in the packet is succeeded by the candidate...
if (PacketSU->isSucc(SU)) {
for (unsigned i = 0; i < PacketSU->Succs.size(); ++i) {
// The corner case exist when there is true data
// dependency between candidate and one of current
// packet members, this dep is on predicate reg, and
// there already exist anti dep on the same pred in
// the packet.
if (PacketSU->Succs[i].getSUnit() == SU &&
PacketSU->Succs[i].getKind() == SDep::Data &&
Hexagon::PredRegsRegClass.contains(
PacketSU->Succs[i].getReg()) &&
// Here I know that *VIN is predicate setting instruction
// with true data dep to candidate on the register
// we care about - c) in the above example.
// Now I need to see if there is an anti dependency
// from c) to any other instruction in the
// same packet on the pred reg of interest
RestrictingDepExistInPacket(*VIN,PacketSU->Succs[i].getReg(),
MIToSUnit)) {
return false;
}
}
}
}
// If the above case does not apply, check regular
// complement condition.
// Check that the predicate register is the same and
// that the predicate sense is different
// We also need to differentiate .old vs. .new:
// !p0 is not complimentary to p0.new
unsigned PReg1 = getPredicatedRegister(MI1, QII);
unsigned PReg2 = getPredicatedRegister(MI2, QII);
return ((PReg1 == PReg2) &&
Hexagon::PredRegsRegClass.contains(PReg1) &&
Hexagon::PredRegsRegClass.contains(PReg2) &&
(getPredicateSense(MI1, QII) != getPredicateSense(MI2, QII)) &&
(QII->isDotNewInst(MI1) == QII->isDotNewInst(MI2)));
}
// initPacketizerState - Initialize packetizer flags
void HexagonPacketizerList::initPacketizerState() {
Dependence = false;
PromotedToDotNew = false;
GlueToNewValueJump = false;
GlueAllocframeStore = false;
FoundSequentialDependence = false;
return;
}
// ignorePseudoInstruction - Ignore bundling of pseudo instructions.
bool HexagonPacketizerList::ignorePseudoInstruction(MachineInstr *MI,
MachineBasicBlock *MBB) {
if (MI->isDebugValue())
return true;
// We must print out inline assembly
if (MI->isInlineAsm())
return false;
// We check if MI has any functional units mapped to it.
// If it doesn't, we ignore the instruction.
const MCInstrDesc& TID = MI->getDesc();
unsigned SchedClass = TID.getSchedClass();
const InstrStage* IS =
ResourceTracker->getInstrItins()->beginStage(SchedClass);
unsigned FuncUnits = IS->getUnits();
return !FuncUnits;
}
// isSoloInstruction: - Returns true for instructions that must be
// scheduled in their own packet.
bool HexagonPacketizerList::isSoloInstruction(MachineInstr *MI) {
if (MI->isInlineAsm())
return true;
if (MI->isEHLabel())
return true;
// From Hexagon V4 Programmer's Reference Manual 3.4.4 Grouping constraints:
// trap, pause, barrier, icinva, isync, and syncht are solo instructions.
// They must not be grouped with other instructions in a packet.
if (IsSchedBarrier(MI))
return true;
return false;
}
// isLegalToPacketizeTogether:
// SUI is the current instruction that is out side of the current packet.
// SUJ is the current instruction inside the current packet against which that
// SUI will be packetized.
bool HexagonPacketizerList::isLegalToPacketizeTogether(SUnit *SUI, SUnit *SUJ) {
MachineInstr *I = SUI->getInstr();
MachineInstr *J = SUJ->getInstr();
assert(I && J && "Unable to packetize null instruction!");
const MCInstrDesc &MCIDI = I->getDesc();
const MCInstrDesc &MCIDJ = J->getDesc();
MachineBasicBlock::iterator II = I;
const unsigned FrameSize = MF.getFrameInfo()->getStackSize();
const HexagonRegisterInfo *QRI =
(const HexagonRegisterInfo *)MF.getSubtarget().getRegisterInfo();
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
// Inline asm cannot go in the packet.
if (I->getOpcode() == Hexagon::INLINEASM)
llvm_unreachable("Should not meet inline asm here!");
if (isSoloInstruction(I))
llvm_unreachable("Should not meet solo instr here!");
// A save callee-save register function call can only be in a packet
// with instructions that don't write to the callee-save registers.
if ((QII->isSaveCalleeSavedRegsCall(I) &&
DoesModifyCalleeSavedReg(J, QRI)) ||
(QII->isSaveCalleeSavedRegsCall(J) &&
DoesModifyCalleeSavedReg(I, QRI))) {
Dependence = true;
return false;
}
// Two control flow instructions cannot go in the same packet.
if (IsControlFlow(I) && IsControlFlow(J)) {
Dependence = true;
return false;
}
// A LoopN instruction cannot appear in the same packet as a jump or call.
if (IsLoopN(I) &&
(IsDirectJump(J) || MCIDJ.isCall() || QII->isDeallocRet(J))) {
Dependence = true;
return false;
}
if (IsLoopN(J) &&
(IsDirectJump(I) || MCIDI.isCall() || QII->isDeallocRet(I))) {
Dependence = true;
return false;
}
// dealloc_return cannot appear in the same packet as a conditional or
// unconditional jump.
if (QII->isDeallocRet(I) &&
(MCIDJ.isBranch() || MCIDJ.isCall() || MCIDJ.isBarrier())) {
Dependence = true;
return false;
}
// V4 allows dual store. But does not allow second store, if the
// first store is not in SLOT0. New value store, new value jump,
// dealloc_return and memop always take SLOT0.
// Arch spec 3.4.4.2
if (QRI->Subtarget.hasV4TOps()) {
if (MCIDI.mayStore() && MCIDJ.mayStore() &&
(QII->isNewValueInst(J) || QII->isMemOp(J) || QII->isMemOp(I))) {
Dependence = true;
return false;
}
if ((QII->isMemOp(J) && MCIDI.mayStore())
|| (MCIDJ.mayStore() && QII->isMemOp(I))
|| (QII->isMemOp(J) && QII->isMemOp(I))) {
Dependence = true;
return false;
}
//if dealloc_return
if (MCIDJ.mayStore() && QII->isDeallocRet(I)) {
Dependence = true;
return false;
}
// If an instruction feeds new value jump, glue it.
MachineBasicBlock::iterator NextMII = I;
++NextMII;
if (NextMII != I->getParent()->end() && QII->isNewValueJump(NextMII)) {
MachineInstr *NextMI = NextMII;
bool secondRegMatch = false;
bool maintainNewValueJump = false;
if (NextMI->getOperand(1).isReg() &&
I->getOperand(0).getReg() == NextMI->getOperand(1).getReg()) {
secondRegMatch = true;
maintainNewValueJump = true;
}
if (!secondRegMatch &&
I->getOperand(0).getReg() == NextMI->getOperand(0).getReg()) {
maintainNewValueJump = true;
}
for (std::vector<MachineInstr*>::iterator
VI = CurrentPacketMIs.begin(),
VE = CurrentPacketMIs.end();
(VI != VE && maintainNewValueJump); ++VI) {
SUnit *PacketSU = MIToSUnit.find(*VI)->second;
// NVJ can not be part of the dual jump - Arch Spec: section 7.8
if (PacketSU->getInstr()->getDesc().isCall()) {
Dependence = true;
break;
}
// Validate
// 1. Packet does not have a store in it.
// 2. If the first operand of the nvj is newified, and the second
// operand is also a reg, it (second reg) is not defined in
// the same packet.
// 3. If the second operand of the nvj is newified, (which means
// first operand is also a reg), first reg is not defined in
// the same packet.
if (PacketSU->getInstr()->getDesc().mayStore() ||
PacketSU->getInstr()->getOpcode() == Hexagon::S2_allocframe ||
// Check #2.
(!secondRegMatch && NextMI->getOperand(1).isReg() &&
PacketSU->getInstr()->modifiesRegister(
NextMI->getOperand(1).getReg(), QRI)) ||
// Check #3.
(secondRegMatch &&
PacketSU->getInstr()->modifiesRegister(
NextMI->getOperand(0).getReg(), QRI))) {
Dependence = true;
break;
}
}
if (!Dependence)
GlueToNewValueJump = true;
else
return false;
}
}
if (SUJ->isSucc(SUI)) {
for (unsigned i = 0;
(i < SUJ->Succs.size()) && !FoundSequentialDependence;
++i) {
if (SUJ->Succs[i].getSUnit() != SUI) {
continue;
}
SDep::Kind DepType = SUJ->Succs[i].getKind();
// For direct calls:
// Ignore register dependences for call instructions for
// packetization purposes except for those due to r31 and
// predicate registers.
//
// For indirect calls:
// Same as direct calls + check for true dependences to the register
// used in the indirect call.
//
// We completely ignore Order dependences for call instructions
//
// For returns:
// Ignore register dependences for return instructions like jumpr,
// dealloc return unless we have dependencies on the explicit uses
// of the registers used by jumpr (like r31) or dealloc return
// (like r29 or r30).
//
// TODO: Currently, jumpr is handling only return of r31. So, the
// following logic (specificaly IsCallDependent) is working fine.
// We need to enable jumpr for register other than r31 and then,
// we need to rework the last part, where it handles indirect call
// of that (IsCallDependent) function. Bug 6216 is opened for this.
//
unsigned DepReg = 0;
const TargetRegisterClass* RC = nullptr;
if (DepType == SDep::Data) {
DepReg = SUJ->Succs[i].getReg();
RC = QRI->getMinimalPhysRegClass(DepReg);
}
if ((MCIDI.isCall() || MCIDI.isReturn()) &&
(!IsRegDependence(DepType) ||
!IsCallDependent(I, DepType, SUJ->Succs[i].getReg()))) {
/* do nothing */
}
// For instructions that can be promoted to dot-new, try to promote.
else if ((DepType == SDep::Data) &&
CanPromoteToDotNew(I, SUJ, DepReg, MIToSUnit, II, RC) &&
PromoteToDotNew(I, DepType, II, RC)) {
PromotedToDotNew = true;
/* do nothing */
}
else if ((DepType == SDep::Data) &&
(QII->isNewValueJump(I))) {
/* do nothing */
}
// For predicated instructions, if the predicates are complements
// then there can be no dependence.
else if (QII->isPredicated(I) &&
QII->isPredicated(J) &&
ArePredicatesComplements(I, J, MIToSUnit)) {
/* do nothing */
}
else if (IsDirectJump(I) &&
!MCIDJ.isBranch() &&
!MCIDJ.isCall() &&
(DepType == SDep::Order)) {
// Ignore Order dependences between unconditional direct branches
// and non-control-flow instructions
/* do nothing */
}
else if (MCIDI.isConditionalBranch() && (DepType != SDep::Data) &&
(DepType != SDep::Output)) {
// Ignore all dependences for jumps except for true and output
// dependences
/* do nothing */
}
// Ignore output dependences due to superregs. We can
// write to two different subregisters of R1:0 for instance
// in the same cycle
//
//
// Let the
// If neither I nor J defines DepReg, then this is a
// superfluous output dependence. The dependence must be of the
// form:
// R0 = ...
// R1 = ...
// and there is an output dependence between the two instructions
// with
// DepReg = D0
// We want to ignore these dependences.
// Ideally, the dependence constructor should annotate such
// dependences. We can then avoid this relatively expensive check.
//
else if (DepType == SDep::Output) {
// DepReg is the register that's responsible for the dependence.
unsigned DepReg = SUJ->Succs[i].getReg();
// Check if I and J really defines DepReg.
if (I->definesRegister(DepReg) ||
J->definesRegister(DepReg)) {
FoundSequentialDependence = true;
break;
}
}
// We ignore Order dependences for
// 1. Two loads unless they are volatile.
// 2. Two stores in V4 unless they are volatile.
else if ((DepType == SDep::Order) &&
!I->hasOrderedMemoryRef() &&
!J->hasOrderedMemoryRef()) {
if (QRI->Subtarget.hasV4TOps() &&
// hexagonv4 allows dual store.
MCIDI.mayStore() && MCIDJ.mayStore()) {
/* do nothing */
}
// store followed by store-- not OK on V2
// store followed by load -- not OK on all (OK if addresses
// are not aliased)
// load followed by store -- OK on all
// load followed by load -- OK on all
else if ( !MCIDJ.mayStore()) {
/* do nothing */
}
else {
FoundSequentialDependence = true;
break;
}
}
// For V4, special case ALLOCFRAME. Even though there is dependency
// between ALLOCFRAME and subsequent store, allow it to be
// packetized in a same packet. This implies that the store is using
// caller's SP. Hence, offset needs to be updated accordingly.
else if (DepType == SDep::Data
&& QRI->Subtarget.hasV4TOps()
&& J->getOpcode() == Hexagon::S2_allocframe
&& (I->getOpcode() == Hexagon::S2_storerd_io
|| I->getOpcode() == Hexagon::S2_storeri_io
|| I->getOpcode() == Hexagon::S2_storerb_io)
&& I->getOperand(0).getReg() == QRI->getStackRegister()
&& QII->isValidOffset(I->getOpcode(),
I->getOperand(1).getImm() -
(FrameSize + HEXAGON_LRFP_SIZE)))
{
GlueAllocframeStore = true;
// Since this store is to be glued with allocframe in the same
// packet, it will use SP of the previous stack frame, i.e
// caller's SP. Therefore, we need to recalculate offset according
// to this change.
I->getOperand(1).setImm(I->getOperand(1).getImm() -
(FrameSize + HEXAGON_LRFP_SIZE));
}
//
// Skip over anti-dependences. Two instructions that are
// anti-dependent can share a packet
//
else if (DepType != SDep::Anti) {
FoundSequentialDependence = true;
break;
}
}
if (FoundSequentialDependence) {
Dependence = true;
return false;
}
}
return true;
}
// isLegalToPruneDependencies
bool HexagonPacketizerList::isLegalToPruneDependencies(SUnit *SUI, SUnit *SUJ) {
MachineInstr *I = SUI->getInstr();
assert(I && SUJ->getInstr() && "Unable to packetize null instruction!");
const unsigned FrameSize = MF.getFrameInfo()->getStackSize();
if (Dependence) {
// Check if the instruction was promoted to a dot-new. If so, demote it
// back into a dot-old.
if (PromotedToDotNew) {
DemoteToDotOld(I);
}
// Check if the instruction (must be a store) was glued with an Allocframe
// instruction. If so, restore its offset to its original value, i.e. use
// curent SP instead of caller's SP.
if (GlueAllocframeStore) {
I->getOperand(1).setImm(I->getOperand(1).getImm() +
FrameSize + HEXAGON_LRFP_SIZE);
}
return false;
}
return true;
}
MachineBasicBlock::iterator
HexagonPacketizerList::addToPacket(MachineInstr *MI) {
MachineBasicBlock::iterator MII = MI;
MachineBasicBlock *MBB = MI->getParent();
const HexagonInstrInfo *QII = (const HexagonInstrInfo *) TII;
if (GlueToNewValueJump) {
++MII;
MachineInstr *nvjMI = MII;
assert(ResourceTracker->canReserveResources(MI));
ResourceTracker->reserveResources(MI);
if ((QII->isExtended(MI) || QII->isConstExtended(MI)) &&
!tryAllocateResourcesForConstExt(MI)) {
endPacket(MBB, MI);
ResourceTracker->reserveResources(MI);
assert(canReserveResourcesForConstExt(MI) &&
"Ensure that there is a slot");
reserveResourcesForConstExt(MI);
// Reserve resources for new value jump constant extender.
assert(canReserveResourcesForConstExt(MI) &&
"Ensure that there is a slot");
reserveResourcesForConstExt(nvjMI);
assert(ResourceTracker->canReserveResources(nvjMI) &&
"Ensure that there is a slot");
} else if ( // Extended instruction takes two slots in the packet.
// Try reserve and allocate 4-byte in the current packet first.
(QII->isExtended(nvjMI)
&& (!tryAllocateResourcesForConstExt(nvjMI)
|| !ResourceTracker->canReserveResources(nvjMI)))
|| // For non-extended instruction, no need to allocate extra 4 bytes.
(!QII->isExtended(nvjMI) &&
!ResourceTracker->canReserveResources(nvjMI)))
{
endPacket(MBB, MI);
// A new and empty packet starts.
// We are sure that the resources requirements can be satisfied.
// Therefore, do not need to call "canReserveResources" anymore.
ResourceTracker->reserveResources(MI);
if (QII->isExtended(nvjMI))
reserveResourcesForConstExt(nvjMI);
}
// Here, we are sure that "reserveResources" would succeed.
ResourceTracker->reserveResources(nvjMI);
CurrentPacketMIs.push_back(MI);
CurrentPacketMIs.push_back(nvjMI);
} else {
if ( (QII->isExtended(MI) || QII->isConstExtended(MI))
&& ( !tryAllocateResourcesForConstExt(MI)
|| !ResourceTracker->canReserveResources(MI)))
{
endPacket(MBB, MI);
// Check if the instruction was promoted to a dot-new. If so, demote it
// back into a dot-old
if (PromotedToDotNew) {
DemoteToDotOld(MI);
}
reserveResourcesForConstExt(MI);
}
// In case that "MI" is not an extended insn,
// the resource availability has already been checked.
ResourceTracker->reserveResources(MI);
CurrentPacketMIs.push_back(MI);
}
return MII;
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
FunctionPass *llvm::createHexagonPacketizer() {
return new HexagonPacketizer();
}
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