vim/YouCompleteMe
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
81811964c3
YouCompleteMe/cpp/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
Strahinja Val Markovic 8480549b46 Adding llvm and clang in-source
2012-07-05 17:51:06 -07:00

1545 lines
56 KiB
C++
Raw Blame History

//===-- LiveIntervalAnalysis.cpp - Live Interval Analysis -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the LiveInterval analysis pass which is used
// by the Linear Scan Register allocator. This pass linearizes the
// basic blocks of the function in DFS order and uses the
// LiveVariables pass to conservatively compute live intervals for
// each virtual and physical register.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "regalloc"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/Value.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h"
#include <algorithm>
#include <limits>
#include <cmath>
using namespace llvm;
// Hidden options for help debugging.
static cl::opt<bool> DisableReMat("disable-rematerialization",
cl::init(false), cl::Hidden);
STATISTIC(numIntervals , "Number of original intervals");
char LiveIntervals::ID = 0;
INITIALIZE_PASS_BEGIN(LiveIntervals, "liveintervals",
"Live Interval Analysis", false, false)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_DEPENDENCY(LiveVariables)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
INITIALIZE_PASS_END(LiveIntervals, "liveintervals",
"Live Interval Analysis", false, false)
void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<AliasAnalysis>();
AU.addPreserved<AliasAnalysis>();
AU.addRequired<LiveVariables>();
AU.addPreserved<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
AU.addPreserved<SlotIndexes>();
AU.addRequiredTransitive<SlotIndexes>();
MachineFunctionPass::getAnalysisUsage(AU);
}
void LiveIntervals::releaseMemory() {
// Free the live intervals themselves.
for (DenseMap<unsigned, LiveInterval*>::iterator I = r2iMap_.begin(),
E = r2iMap_.end(); I != E; ++I)
delete I->second;
r2iMap_.clear();
RegMaskSlots.clear();
RegMaskBits.clear();
RegMaskBlocks.clear();
// Release VNInfo memory regions, VNInfo objects don't need to be dtor'd.
VNInfoAllocator.Reset();
}
/// runOnMachineFunction - Register allocate the whole function
///
bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
mf_ = &fn;
mri_ = &mf_->getRegInfo();
tm_ = &fn.getTarget();
tri_ = tm_->getRegisterInfo();
tii_ = tm_->getInstrInfo();
aa_ = &getAnalysis<AliasAnalysis>();
lv_ = &getAnalysis<LiveVariables>();
indexes_ = &getAnalysis<SlotIndexes>();
allocatableRegs_ = tri_->getAllocatableSet(fn);
reservedRegs_ = tri_->getReservedRegs(fn);
computeIntervals();
numIntervals += getNumIntervals();
DEBUG(dump());
return true;
}
/// print - Implement the dump method.
void LiveIntervals::print(raw_ostream &OS, const Module* ) const {
OS << "********** INTERVALS **********\n";
// Dump the physregs.
for (unsigned Reg = 1, RegE = tri_->getNumRegs(); Reg != RegE; ++Reg)
if (const LiveInterval *LI = r2iMap_.lookup(Reg)) {
LI->print(OS, tri_);
OS << '\n';
}
// Dump the virtregs.
for (unsigned Reg = 0, RegE = mri_->getNumVirtRegs(); Reg != RegE; ++Reg)
if (const LiveInterval *LI =
r2iMap_.lookup(TargetRegisterInfo::index2VirtReg(Reg))) {
LI->print(OS, tri_);
OS << '\n';
}
printInstrs(OS);
}
void LiveIntervals::printInstrs(raw_ostream &OS) const {
OS << "********** MACHINEINSTRS **********\n";
mf_->print(OS, indexes_);
}
void LiveIntervals::dumpInstrs() const {
printInstrs(dbgs());
}
static
bool MultipleDefsBySameMI(const MachineInstr &MI, unsigned MOIdx) {
unsigned Reg = MI.getOperand(MOIdx).getReg();
for (unsigned i = MOIdx+1, e = MI.getNumOperands(); i < e; ++i) {
const MachineOperand &MO = MI.getOperand(i);
if (!MO.isReg())
continue;
if (MO.getReg() == Reg && MO.isDef()) {
assert(MI.getOperand(MOIdx).getSubReg() != MO.getSubReg() &&
MI.getOperand(MOIdx).getSubReg() &&
(MO.getSubReg() || MO.isImplicit()));
return true;
}
}
return false;
}
/// isPartialRedef - Return true if the specified def at the specific index is
/// partially re-defining the specified live interval. A common case of this is
/// a definition of the sub-register.
bool LiveIntervals::isPartialRedef(SlotIndex MIIdx, MachineOperand &MO,
LiveInterval &interval) {
if (!MO.getSubReg() || MO.isEarlyClobber())
return false;
SlotIndex RedefIndex = MIIdx.getRegSlot();
const LiveRange *OldLR =
interval.getLiveRangeContaining(RedefIndex.getRegSlot(true));
MachineInstr *DefMI = getInstructionFromIndex(OldLR->valno->def);
if (DefMI != 0) {
return DefMI->findRegisterDefOperandIdx(interval.reg) != -1;
}
return false;
}
void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
MachineBasicBlock::iterator mi,
SlotIndex MIIdx,
MachineOperand& MO,
unsigned MOIdx,
LiveInterval &interval) {
DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_));
// Virtual registers may be defined multiple times (due to phi
// elimination and 2-addr elimination). Much of what we do only has to be
// done once for the vreg. We use an empty interval to detect the first
// time we see a vreg.
LiveVariables::VarInfo& vi = lv_->getVarInfo(interval.reg);
if (interval.empty()) {
// Get the Idx of the defining instructions.
SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
// Make sure the first definition is not a partial redefinition.
assert(!MO.readsReg() && "First def cannot also read virtual register "
"missing <undef> flag?");
VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator);
assert(ValNo->id == 0 && "First value in interval is not 0?");
// Loop over all of the blocks that the vreg is defined in. There are
// two cases we have to handle here. The most common case is a vreg
// whose lifetime is contained within a basic block. In this case there
// will be a single kill, in MBB, which comes after the definition.
if (vi.Kills.size() == 1 && vi.Kills[0]->getParent() == mbb) {
// FIXME: what about dead vars?
SlotIndex killIdx;
if (vi.Kills[0] != mi)
killIdx = getInstructionIndex(vi.Kills[0]).getRegSlot();
else
killIdx = defIndex.getDeadSlot();
// If the kill happens after the definition, we have an intra-block
// live range.
if (killIdx > defIndex) {
assert(vi.AliveBlocks.empty() &&
"Shouldn't be alive across any blocks!");
LiveRange LR(defIndex, killIdx, ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR << "\n");
return;
}
}
// The other case we handle is when a virtual register lives to the end
// of the defining block, potentially live across some blocks, then is
// live into some number of blocks, but gets killed. Start by adding a
// range that goes from this definition to the end of the defining block.
LiveRange NewLR(defIndex, getMBBEndIdx(mbb), ValNo);
DEBUG(dbgs() << " +" << NewLR);
interval.addRange(NewLR);
bool PHIJoin = lv_->isPHIJoin(interval.reg);
if (PHIJoin) {
// A phi join register is killed at the end of the MBB and revived as a new
// valno in the killing blocks.
assert(vi.AliveBlocks.empty() && "Phi join can't pass through blocks");
DEBUG(dbgs() << " phi-join");
ValNo->setHasPHIKill(true);
} else {
// Iterate over all of the blocks that the variable is completely
// live in, adding [insrtIndex(begin), instrIndex(end)+4) to the
// live interval.
for (SparseBitVector<>::iterator I = vi.AliveBlocks.begin(),
E = vi.AliveBlocks.end(); I != E; ++I) {
MachineBasicBlock *aliveBlock = mf_->getBlockNumbered(*I);
LiveRange LR(getMBBStartIdx(aliveBlock), getMBBEndIdx(aliveBlock), ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR);
}
}
// Finally, this virtual register is live from the start of any killing
// block to the 'use' slot of the killing instruction.
for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) {
MachineInstr *Kill = vi.Kills[i];
SlotIndex Start = getMBBStartIdx(Kill->getParent());
SlotIndex killIdx = getInstructionIndex(Kill).getRegSlot();
// Create interval with one of a NEW value number. Note that this value
// number isn't actually defined by an instruction, weird huh? :)
if (PHIJoin) {
assert(getInstructionFromIndex(Start) == 0 &&
"PHI def index points at actual instruction.");
ValNo = interval.getNextValue(Start, VNInfoAllocator);
ValNo->setIsPHIDef(true);
}
LiveRange LR(Start, killIdx, ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR);
}
} else {
if (MultipleDefsBySameMI(*mi, MOIdx))
// Multiple defs of the same virtual register by the same instruction.
// e.g. %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ...
// This is likely due to elimination of REG_SEQUENCE instructions. Return
// here since there is nothing to do.
return;
// If this is the second time we see a virtual register definition, it
// must be due to phi elimination or two addr elimination. If this is
// the result of two address elimination, then the vreg is one of the
// def-and-use register operand.
// It may also be partial redef like this:
// 80 %reg1041:6<def> = VSHRNv4i16 %reg1034<kill>, 12, pred:14, pred:%reg0
// 120 %reg1041:5<def> = VSHRNv4i16 %reg1039<kill>, 12, pred:14, pred:%reg0
bool PartReDef = isPartialRedef(MIIdx, MO, interval);
if (PartReDef || mi->isRegTiedToUseOperand(MOIdx)) {
// If this is a two-address definition, then we have already processed
// the live range. The only problem is that we didn't realize there
// are actually two values in the live interval. Because of this we
// need to take the LiveRegion that defines this register and split it
// into two values.
SlotIndex RedefIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
const LiveRange *OldLR =
interval.getLiveRangeContaining(RedefIndex.getRegSlot(true));
VNInfo *OldValNo = OldLR->valno;
SlotIndex DefIndex = OldValNo->def.getRegSlot();
// Delete the previous value, which should be short and continuous,
// because the 2-addr copy must be in the same MBB as the redef.
interval.removeRange(DefIndex, RedefIndex);
// The new value number (#1) is defined by the instruction we claimed
// defined value #0.
VNInfo *ValNo = interval.createValueCopy(OldValNo, VNInfoAllocator);
// Value#0 is now defined by the 2-addr instruction.
OldValNo->def = RedefIndex;
// Add the new live interval which replaces the range for the input copy.
LiveRange LR(DefIndex, RedefIndex, ValNo);
DEBUG(dbgs() << " replace range with " << LR);
interval.addRange(LR);
// If this redefinition is dead, we need to add a dummy unit live
// range covering the def slot.
if (MO.isDead())
interval.addRange(LiveRange(RedefIndex, RedefIndex.getDeadSlot(),
OldValNo));
DEBUG({
dbgs() << " RESULT: ";
interval.print(dbgs(), tri_);
});
} else if (lv_->isPHIJoin(interval.reg)) {
// In the case of PHI elimination, each variable definition is only
// live until the end of the block. We've already taken care of the
// rest of the live range.
SlotIndex defIndex = MIIdx.getRegSlot();
if (MO.isEarlyClobber())
defIndex = MIIdx.getRegSlot(true);
VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator);
SlotIndex killIndex = getMBBEndIdx(mbb);
LiveRange LR(defIndex, killIndex, ValNo);
interval.addRange(LR);
ValNo->setHasPHIKill(true);
DEBUG(dbgs() << " phi-join +" << LR);
} else {
llvm_unreachable("Multiply defined register");
}
}
DEBUG(dbgs() << '\n');
}
static bool isRegLiveIntoSuccessor(const MachineBasicBlock *MBB, unsigned Reg) {
for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end();
SI != SE; ++SI) {
const MachineBasicBlock* succ = *SI;
if (succ->isLiveIn(Reg))
return true;
}
return false;
}
void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator mi,
SlotIndex MIIdx,
MachineOperand& MO,
LiveInterval &interval) {
DEBUG(dbgs() << "\t\tregister: " << PrintReg(interval.reg, tri_));
SlotIndex baseIndex = MIIdx;
SlotIndex start = baseIndex.getRegSlot(MO.isEarlyClobber());
SlotIndex end = start;
// If it is not used after definition, it is considered dead at
// the instruction defining it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
// For earlyclobbers, the defSlot was pushed back one; the extra
// advance below compensates.
if (MO.isDead()) {
DEBUG(dbgs() << " dead");
end = start.getDeadSlot();
goto exit;
}
// If it is not dead on definition, it must be killed by a
// subsequent instruction. Hence its interval is:
// [defSlot(def), useSlot(kill)+1)
baseIndex = baseIndex.getNextIndex();
while (++mi != MBB->end()) {
if (mi->isDebugValue())
continue;
if (getInstructionFromIndex(baseIndex) == 0)
baseIndex = indexes_->getNextNonNullIndex(baseIndex);
if (mi->killsRegister(interval.reg, tri_)) {
DEBUG(dbgs() << " killed");
end = baseIndex.getRegSlot();
goto exit;
} else {
int DefIdx = mi->findRegisterDefOperandIdx(interval.reg,false,false,tri_);
if (DefIdx != -1) {
if (mi->isRegTiedToUseOperand(DefIdx)) {
// Two-address instruction.
end = baseIndex.getRegSlot(mi->getOperand(DefIdx).isEarlyClobber());
} else {
// Another instruction redefines the register before it is ever read.
// Then the register is essentially dead at the instruction that
// defines it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
DEBUG(dbgs() << " dead");
end = start.getDeadSlot();
}
goto exit;
}
}
baseIndex = baseIndex.getNextIndex();
}
// If we get here the register *should* be live out.
assert(!isAllocatable(interval.reg) && "Physregs shouldn't be live out!");
// FIXME: We need saner rules for reserved regs.
if (isReserved(interval.reg)) {
end = start.getDeadSlot();
} else {
// Unreserved, unallocable registers like EFLAGS can be live across basic
// block boundaries.
assert(isRegLiveIntoSuccessor(MBB, interval.reg) &&
"Unreserved reg not live-out?");
end = getMBBEndIdx(MBB);
}
exit:
assert(start < end && "did not find end of interval?");
// Already exists? Extend old live interval.
VNInfo *ValNo = interval.getVNInfoAt(start);
bool Extend = ValNo != 0;
if (!Extend)
ValNo = interval.getNextValue(start, VNInfoAllocator);
LiveRange LR(start, end, ValNo);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR << '\n');
}
void LiveIntervals::handleRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MI,
SlotIndex MIIdx,
MachineOperand& MO,
unsigned MOIdx) {
if (TargetRegisterInfo::isVirtualRegister(MO.getReg()))
handleVirtualRegisterDef(MBB, MI, MIIdx, MO, MOIdx,
getOrCreateInterval(MO.getReg()));
else
handlePhysicalRegisterDef(MBB, MI, MIIdx, MO,
getOrCreateInterval(MO.getReg()));
}
void LiveIntervals::handleLiveInRegister(MachineBasicBlock *MBB,
SlotIndex MIIdx,
LiveInterval &interval) {
assert(TargetRegisterInfo::isPhysicalRegister(interval.reg) &&
"Only physical registers can be live in.");
assert((!isAllocatable(interval.reg) || MBB->getParent()->begin() ||
MBB->isLandingPad()) &&
"Allocatable live-ins only valid for entry blocks and landing pads.");
DEBUG(dbgs() << "\t\tlivein register: " << PrintReg(interval.reg, tri_));
// Look for kills, if it reaches a def before it's killed, then it shouldn't
// be considered a livein.
MachineBasicBlock::iterator mi = MBB->begin();
MachineBasicBlock::iterator E = MBB->end();
// Skip over DBG_VALUE at the start of the MBB.
if (mi != E && mi->isDebugValue()) {
while (++mi != E && mi->isDebugValue())
;
if (mi == E)
// MBB is empty except for DBG_VALUE's.
return;
}
SlotIndex baseIndex = MIIdx;
SlotIndex start = baseIndex;
if (getInstructionFromIndex(baseIndex) == 0)
baseIndex = indexes_->getNextNonNullIndex(baseIndex);
SlotIndex end = baseIndex;
bool SeenDefUse = false;
while (mi != E) {
if (mi->killsRegister(interval.reg, tri_)) {
DEBUG(dbgs() << " killed");
end = baseIndex.getRegSlot();
SeenDefUse = true;
break;
} else if (mi->modifiesRegister(interval.reg, tri_)) {
// Another instruction redefines the register before it is ever read.
// Then the register is essentially dead at the instruction that defines
// it. Hence its interval is:
// [defSlot(def), defSlot(def)+1)
DEBUG(dbgs() << " dead");
end = start.getDeadSlot();
SeenDefUse = true;
break;
}
while (++mi != E && mi->isDebugValue())
// Skip over DBG_VALUE.
;
if (mi != E)
baseIndex = indexes_->getNextNonNullIndex(baseIndex);
}
// Live-in register might not be used at all.
if (!SeenDefUse) {
if (isAllocatable(interval.reg) ||
!isRegLiveIntoSuccessor(MBB, interval.reg)) {
// Allocatable registers are never live through.
// Non-allocatable registers that aren't live into any successors also
// aren't live through.
DEBUG(dbgs() << " dead");
return;
} else {
// If we get here the register is non-allocatable and live into some
// successor. We'll conservatively assume it's live-through.
DEBUG(dbgs() << " live through");
end = getMBBEndIdx(MBB);
}
}
SlotIndex defIdx = getMBBStartIdx(MBB);
assert(getInstructionFromIndex(defIdx) == 0 &&
"PHI def index points at actual instruction.");
VNInfo *vni = interval.getNextValue(defIdx, VNInfoAllocator);
vni->setIsPHIDef(true);
LiveRange LR(start, end, vni);
interval.addRange(LR);
DEBUG(dbgs() << " +" << LR << '\n');
}
/// computeIntervals - computes the live intervals for virtual
/// registers. for some ordering of the machine instructions [1,N] a
/// live interval is an interval [i, j) where 1 <= i <= j < N for
/// which a variable is live
void LiveIntervals::computeIntervals() {
DEBUG(dbgs() << "********** COMPUTING LIVE INTERVALS **********\n"
<< "********** Function: "
<< ((Value*)mf_->getFunction())->getName() << '\n');
RegMaskBlocks.resize(mf_->getNumBlockIDs());
SmallVector<unsigned, 8> UndefUses;
for (MachineFunction::iterator MBBI = mf_->begin(), E = mf_->end();
MBBI != E; ++MBBI) {
MachineBasicBlock *MBB = MBBI;
RegMaskBlocks[MBB->getNumber()].first = RegMaskSlots.size();
if (MBB->empty())
continue;
// Track the index of the current machine instr.
SlotIndex MIIndex = getMBBStartIdx(MBB);
DEBUG(dbgs() << "BB#" << MBB->getNumber()
<< ":\t\t# derived from " << MBB->getName() << "\n");
// Create intervals for live-ins to this BB first.
for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(),
LE = MBB->livein_end(); LI != LE; ++LI) {
handleLiveInRegister(MBB, MIIndex, getOrCreateInterval(*LI));
}
// Skip over empty initial indices.
if (getInstructionFromIndex(MIIndex) == 0)
MIIndex = indexes_->getNextNonNullIndex(MIIndex);
for (MachineBasicBlock::iterator MI = MBB->begin(), miEnd = MBB->end();
MI != miEnd; ++MI) {
DEBUG(dbgs() << MIIndex << "\t" << *MI);
if (MI->isDebugValue())
continue;
assert(indexes_->getInstructionFromIndex(MIIndex) == MI &&
"Lost SlotIndex synchronization");
// Handle defs.
for (int i = MI->getNumOperands() - 1; i >= 0; --i) {
MachineOperand &MO = MI->getOperand(i);
// Collect register masks.
if (MO.isRegMask()) {
RegMaskSlots.push_back(MIIndex.getRegSlot());
RegMaskBits.push_back(MO.getRegMask());
continue;
}
if (!MO.isReg() || !MO.getReg())
continue;
// handle register defs - build intervals
if (MO.isDef())
handleRegisterDef(MBB, MI, MIIndex, MO, i);
else if (MO.isUndef())
UndefUses.push_back(MO.getReg());
}
// Move to the next instr slot.
MIIndex = indexes_->getNextNonNullIndex(MIIndex);
}
// Compute the number of register mask instructions in this block.
std::pair<unsigned, unsigned> &RMB = RegMaskBlocks[MBB->getNumber()];
RMB.second = RegMaskSlots.size() - RMB.first;;
}
// Create empty intervals for registers defined by implicit_def's (except
// for those implicit_def that define values which are liveout of their
// blocks.
for (unsigned i = 0, e = UndefUses.size(); i != e; ++i) {
unsigned UndefReg = UndefUses[i];
(void)getOrCreateInterval(UndefReg);
}
}
LiveInterval* LiveIntervals::createInterval(unsigned reg) {
float Weight = TargetRegisterInfo::isPhysicalRegister(reg) ? HUGE_VALF : 0.0F;
return new LiveInterval(reg, Weight);
}
/// dupInterval - Duplicate a live interval. The caller is responsible for
/// managing the allocated memory.
LiveInterval* LiveIntervals::dupInterval(LiveInterval *li) {
LiveInterval *NewLI = createInterval(li->reg);
NewLI->Copy(*li, mri_, getVNInfoAllocator());
return NewLI;
}
/// shrinkToUses - After removing some uses of a register, shrink its live
/// range to just the remaining uses. This method does not compute reaching
/// defs for new uses, and it doesn't remove dead defs.
bool LiveIntervals::shrinkToUses(LiveInterval *li,
SmallVectorImpl<MachineInstr*> *dead) {
DEBUG(dbgs() << "Shrink: " << *li << '\n');
assert(TargetRegisterInfo::isVirtualRegister(li->reg)
&& "Can only shrink virtual registers");
// Find all the values used, including PHI kills.
SmallVector<std::pair<SlotIndex, VNInfo*>, 16> WorkList;
// Blocks that have already been added to WorkList as live-out.
SmallPtrSet<MachineBasicBlock*, 16> LiveOut;
// Visit all instructions reading li->reg.
for (MachineRegisterInfo::reg_iterator I = mri_->reg_begin(li->reg);
MachineInstr *UseMI = I.skipInstruction();) {
if (UseMI->isDebugValue() || !UseMI->readsVirtualRegister(li->reg))
continue;
SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot();
// Note: This intentionally picks up the wrong VNI in case of an EC redef.
// See below.
VNInfo *VNI = li->getVNInfoBefore(Idx);
if (!VNI) {
// This shouldn't happen: readsVirtualRegister returns true, but there is
// no live value. It is likely caused by a target getting <undef> flags
// wrong.
DEBUG(dbgs() << Idx << '\t' << *UseMI
<< "Warning: Instr claims to read non-existent value in "
<< *li << '\n');
continue;
}
// Special case: An early-clobber tied operand reads and writes the
// register one slot early. The getVNInfoBefore call above would have
// picked up the value defined by UseMI. Adjust the kill slot and value.
if (SlotIndex::isSameInstr(VNI->def, Idx)) {
Idx = VNI->def;
VNI = li->getVNInfoBefore(Idx);
assert(VNI && "Early-clobber tied value not available");
}
WorkList.push_back(std::make_pair(Idx, VNI));
}
// Create a new live interval with only minimal live segments per def.
LiveInterval NewLI(li->reg, 0);
for (LiveInterval::vni_iterator I = li->vni_begin(), E = li->vni_end();
I != E; ++I) {
VNInfo *VNI = *I;
if (VNI->isUnused())
continue;
NewLI.addRange(LiveRange(VNI->def, VNI->def.getDeadSlot(), VNI));
}
// Keep track of the PHIs that are in use.
SmallPtrSet<VNInfo*, 8> UsedPHIs;
// Extend intervals to reach all uses in WorkList.
while (!WorkList.empty()) {
SlotIndex Idx = WorkList.back().first;
VNInfo *VNI = WorkList.back().second;
WorkList.pop_back();
const MachineBasicBlock *MBB = getMBBFromIndex(Idx.getPrevSlot());
SlotIndex BlockStart = getMBBStartIdx(MBB);
// Extend the live range for VNI to be live at Idx.
if (VNInfo *ExtVNI = NewLI.extendInBlock(BlockStart, Idx)) {
(void)ExtVNI;
assert(ExtVNI == VNI && "Unexpected existing value number");
// Is this a PHIDef we haven't seen before?
if (!VNI->isPHIDef() || VNI->def != BlockStart || !UsedPHIs.insert(VNI))
continue;
// The PHI is live, make sure the predecessors are live-out.
for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
if (!LiveOut.insert(*PI))
continue;
SlotIndex Stop = getMBBEndIdx(*PI);
// A predecessor is not required to have a live-out value for a PHI.
if (VNInfo *PVNI = li->getVNInfoBefore(Stop))
WorkList.push_back(std::make_pair(Stop, PVNI));
}
continue;
}
// VNI is live-in to MBB.
DEBUG(dbgs() << " live-in at " << BlockStart << '\n');
NewLI.addRange(LiveRange(BlockStart, Idx, VNI));
// Make sure VNI is live-out from the predecessors.
for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
if (!LiveOut.insert(*PI))
continue;
SlotIndex Stop = getMBBEndIdx(*PI);
assert(li->getVNInfoBefore(Stop) == VNI &&
"Wrong value out of predecessor");
WorkList.push_back(std::make_pair(Stop, VNI));
}
}
// Handle dead values.
bool CanSeparate = false;
for (LiveInterval::vni_iterator I = li->vni_begin(), E = li->vni_end();
I != E; ++I) {
VNInfo *VNI = *I;
if (VNI->isUnused())
continue;
LiveInterval::iterator LII = NewLI.FindLiveRangeContaining(VNI->def);
assert(LII != NewLI.end() && "Missing live range for PHI");
if (LII->end != VNI->def.getDeadSlot())
continue;
if (VNI->isPHIDef()) {
// This is a dead PHI. Remove it.
VNI->setIsUnused(true);
NewLI.removeRange(*LII);
DEBUG(dbgs() << "Dead PHI at " << VNI->def << " may separate interval\n");
CanSeparate = true;
} else {
// This is a dead def. Make sure the instruction knows.
MachineInstr *MI = getInstructionFromIndex(VNI->def);
assert(MI && "No instruction defining live value");
MI->addRegisterDead(li->reg, tri_);
if (dead && MI->allDefsAreDead()) {
DEBUG(dbgs() << "All defs dead: " << VNI->def << '\t' << *MI);
dead->push_back(MI);
}
}
}
// Move the trimmed ranges back.
li->ranges.swap(NewLI.ranges);
DEBUG(dbgs() << "Shrunk: " << *li << '\n');
return CanSeparate;
}
//===----------------------------------------------------------------------===//
// Register allocator hooks.
//
void LiveIntervals::addKillFlags() {
for (iterator I = begin(), E = end(); I != E; ++I) {
unsigned Reg = I->first;
if (TargetRegisterInfo::isPhysicalRegister(Reg))
continue;
if (mri_->reg_nodbg_empty(Reg))
continue;
LiveInterval *LI = I->second;
// Every instruction that kills Reg corresponds to a live range end point.
for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE;
++RI) {
// A block index indicates an MBB edge.
if (RI->end.isBlock())
continue;
MachineInstr *MI = getInstructionFromIndex(RI->end);
if (!MI)
continue;
MI->addRegisterKilled(Reg, NULL);
}
}
}
/// getReMatImplicitUse - If the remat definition MI has one (for now, we only
/// allow one) virtual register operand, then its uses are implicitly using
/// the register. Returns the virtual register.
unsigned LiveIntervals::getReMatImplicitUse(const LiveInterval &li,
MachineInstr *MI) const {
unsigned RegOp = 0;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || !MO.isUse())
continue;
unsigned Reg = MO.getReg();
if (Reg == 0 || Reg == li.reg)
continue;
if (TargetRegisterInfo::isPhysicalRegister(Reg) && !isAllocatable(Reg))
continue;
RegOp = MO.getReg();
break; // Found vreg operand - leave the loop.
}
return RegOp;
}
/// isValNoAvailableAt - Return true if the val# of the specified interval
/// which reaches the given instruction also reaches the specified use index.
bool LiveIntervals::isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI,
SlotIndex UseIdx) const {
VNInfo *UValNo = li.getVNInfoAt(UseIdx);
return UValNo && UValNo == li.getVNInfoAt(getInstructionIndex(MI));
}
/// isReMaterializable - Returns true if the definition MI of the specified
/// val# of the specified interval is re-materializable.
bool
LiveIntervals::isReMaterializable(const LiveInterval &li,
const VNInfo *ValNo, MachineInstr *MI,
const SmallVectorImpl<LiveInterval*> *SpillIs,
bool &isLoad) {
if (DisableReMat)
return false;
if (!tii_->isTriviallyReMaterializable(MI, aa_))
return false;
// Target-specific code can mark an instruction as being rematerializable
// if it has one virtual reg use, though it had better be something like
// a PIC base register which is likely to be live everywhere.
unsigned ImpUse = getReMatImplicitUse(li, MI);
if (ImpUse) {
const LiveInterval &ImpLi = getInterval(ImpUse);
for (MachineRegisterInfo::use_nodbg_iterator
ri = mri_->use_nodbg_begin(li.reg), re = mri_->use_nodbg_end();
ri != re; ++ri) {
MachineInstr *UseMI = &*ri;
SlotIndex UseIdx = getInstructionIndex(UseMI);
if (li.getVNInfoAt(UseIdx) != ValNo)
continue;
if (!isValNoAvailableAt(ImpLi, MI, UseIdx))
return false;
}
// If a register operand of the re-materialized instruction is going to
// be spilled next, then it's not legal to re-materialize this instruction.
if (SpillIs)
for (unsigned i = 0, e = SpillIs->size(); i != e; ++i)
if (ImpUse == (*SpillIs)[i]->reg)
return false;
}
return true;
}
/// isReMaterializable - Returns true if every definition of MI of every
/// val# of the specified interval is re-materializable.
bool
LiveIntervals::isReMaterializable(const LiveInterval &li,
const SmallVectorImpl<LiveInterval*> *SpillIs,
bool &isLoad) {
isLoad = false;
for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
i != e; ++i) {
const VNInfo *VNI = *i;
if (VNI->isUnused())
continue; // Dead val#.
// Is the def for the val# rematerializable?
MachineInstr *ReMatDefMI = getInstructionFromIndex(VNI->def);
if (!ReMatDefMI)
return false;
bool DefIsLoad = false;
if (!ReMatDefMI ||
!isReMaterializable(li, VNI, ReMatDefMI, SpillIs, DefIsLoad))
return false;
isLoad |= DefIsLoad;
}
return true;
}
MachineBasicBlock*
LiveIntervals::intervalIsInOneMBB(const LiveInterval &LI) const {
// A local live range must be fully contained inside the block, meaning it is
// defined and killed at instructions, not at block boundaries. It is not
// live in or or out of any block.
//
// It is technically possible to have a PHI-defined live range identical to a
// single block, but we are going to return false in that case.
SlotIndex Start = LI.beginIndex();
if (Start.isBlock())
return NULL;
SlotIndex Stop = LI.endIndex();
if (Stop.isBlock())
return NULL;
// getMBBFromIndex doesn't need to search the MBB table when both indexes
// belong to proper instructions.
MachineBasicBlock *MBB1 = indexes_->getMBBFromIndex(Start);
MachineBasicBlock *MBB2 = indexes_->getMBBFromIndex(Stop);
return MBB1 == MBB2 ? MBB1 : NULL;
}
float
LiveIntervals::getSpillWeight(bool isDef, bool isUse, unsigned loopDepth) {
// Limit the loop depth ridiculousness.
if (loopDepth > 200)
loopDepth = 200;
// The loop depth is used to roughly estimate the number of times the
// instruction is executed. Something like 10^d is simple, but will quickly
// overflow a float. This expression behaves like 10^d for small d, but is
// more tempered for large d. At d=200 we get 6.7e33 which leaves a bit of
// headroom before overflow.
// By the way, powf() might be unavailable here. For consistency,
// We may take pow(double,double).
float lc = std::pow(1 + (100.0 / (loopDepth + 10)), (double)loopDepth);
return (isDef + isUse) * lc;
}
LiveRange LiveIntervals::addLiveRangeToEndOfBlock(unsigned reg,
MachineInstr* startInst) {
LiveInterval& Interval = getOrCreateInterval(reg);
VNInfo* VN = Interval.getNextValue(
SlotIndex(getInstructionIndex(startInst).getRegSlot()),
getVNInfoAllocator());
VN->setHasPHIKill(true);
LiveRange LR(
SlotIndex(getInstructionIndex(startInst).getRegSlot()),
getMBBEndIdx(startInst->getParent()), VN);
Interval.addRange(LR);
return LR;
}
//===----------------------------------------------------------------------===//
// Register mask functions
//===----------------------------------------------------------------------===//
bool LiveIntervals::checkRegMaskInterference(LiveInterval &LI,
BitVector &UsableRegs) {
if (LI.empty())
return false;
LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end();
// Use a smaller arrays for local live ranges.
ArrayRef<SlotIndex> Slots;
ArrayRef<const uint32_t*> Bits;
if (MachineBasicBlock *MBB = intervalIsInOneMBB(LI)) {
Slots = getRegMaskSlotsInBlock(MBB->getNumber());
Bits = getRegMaskBitsInBlock(MBB->getNumber());
} else {
Slots = getRegMaskSlots();
Bits = getRegMaskBits();
}
// We are going to enumerate all the register mask slots contained in LI.
// Start with a binary search of RegMaskSlots to find a starting point.
ArrayRef<SlotIndex>::iterator SlotI =
std::lower_bound(Slots.begin(), Slots.end(), LiveI->start);
ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
// No slots in range, LI begins after the last call.
if (SlotI == SlotE)
return false;
bool Found = false;
for (;;) {
assert(*SlotI >= LiveI->start);
// Loop over all slots overlapping this segment.
while (*SlotI < LiveI->end) {
// *SlotI overlaps LI. Collect mask bits.
if (!Found) {
// This is the first overlap. Initialize UsableRegs to all ones.
UsableRegs.clear();
UsableRegs.resize(tri_->getNumRegs(), true);
Found = true;
}
// Remove usable registers clobbered by this mask.
UsableRegs.clearBitsNotInMask(Bits[SlotI-Slots.begin()]);
if (++SlotI == SlotE)
return Found;
}
// *SlotI is beyond the current LI segment.
LiveI = LI.advanceTo(LiveI, *SlotI);
if (LiveI == LiveE)
return Found;
// Advance SlotI until it overlaps.
while (*SlotI < LiveI->start)
if (++SlotI == SlotE)
return Found;
}
}
//===----------------------------------------------------------------------===//
// IntervalUpdate class.
//===----------------------------------------------------------------------===//
// HMEditor is a toolkit used by handleMove to trim or extend live intervals.
class LiveIntervals::HMEditor {
private:
LiveIntervals& LIS;
const MachineRegisterInfo& MRI;
const TargetRegisterInfo& TRI;
SlotIndex NewIdx;
typedef std::pair<LiveInterval*, LiveRange*> IntRangePair;
typedef DenseSet<IntRangePair> RangeSet;
struct RegRanges {
LiveRange* Use;
LiveRange* EC;
LiveRange* Dead;
LiveRange* Def;
RegRanges() : Use(0), EC(0), Dead(0), Def(0) {}
};
typedef DenseMap<unsigned, RegRanges> BundleRanges;
public:
HMEditor(LiveIntervals& LIS, const MachineRegisterInfo& MRI,
const TargetRegisterInfo& TRI, SlotIndex NewIdx)
: LIS(LIS), MRI(MRI), TRI(TRI), NewIdx(NewIdx) {}
// Update intervals for all operands of MI from OldIdx to NewIdx.
// This assumes that MI used to be at OldIdx, and now resides at
// NewIdx.
void moveAllRangesFrom(MachineInstr* MI, SlotIndex OldIdx) {
assert(NewIdx != OldIdx && "No-op move? That's a bit strange.");
// Collect the operands.
RangeSet Entering, Internal, Exiting;
bool hasRegMaskOp = false;
collectRanges(MI, Entering, Internal, Exiting, hasRegMaskOp, OldIdx);
// To keep the LiveRanges valid within an interval, move the ranges closest
// to the destination first. This prevents ranges from overlapping, to that
// APIs like removeRange still work.
if (NewIdx < OldIdx) {
moveAllEnteringFrom(OldIdx, Entering);
moveAllInternalFrom(OldIdx, Internal);
moveAllExitingFrom(OldIdx, Exiting);
}
else {
moveAllExitingFrom(OldIdx, Exiting);
moveAllInternalFrom(OldIdx, Internal);
moveAllEnteringFrom(OldIdx, Entering);
}
if (hasRegMaskOp)
updateRegMaskSlots(OldIdx);
#ifndef NDEBUG
LIValidator validator;
validator = std::for_each(Entering.begin(), Entering.end(), validator);
validator = std::for_each(Internal.begin(), Internal.end(), validator);
validator = std::for_each(Exiting.begin(), Exiting.end(), validator);
assert(validator.rangesOk() && "moveAllOperandsFrom broke liveness.");
#endif
}
// Update intervals for all operands of MI to refer to BundleStart's
// SlotIndex.
void moveAllRangesInto(MachineInstr* MI, MachineInstr* BundleStart) {
if (MI == BundleStart)
return; // Bundling instr with itself - nothing to do.
SlotIndex OldIdx = LIS.getSlotIndexes()->getInstructionIndex(MI);
assert(LIS.getSlotIndexes()->getInstructionFromIndex(OldIdx) == MI &&
"SlotIndex <-> Instruction mapping broken for MI");
// Collect all ranges already in the bundle.
MachineBasicBlock::instr_iterator BII(BundleStart);
RangeSet Entering, Internal, Exiting;
bool hasRegMaskOp = false;
collectRanges(BII, Entering, Internal, Exiting, hasRegMaskOp, NewIdx);
assert(!hasRegMaskOp && "Can't have RegMask operand in bundle.");
for (++BII; &*BII == MI || BII->isInsideBundle(); ++BII) {
if (&*BII == MI)
continue;
collectRanges(BII, Entering, Internal, Exiting, hasRegMaskOp, NewIdx);
assert(!hasRegMaskOp && "Can't have RegMask operand in bundle.");
}
BundleRanges BR = createBundleRanges(Entering, Internal, Exiting);
collectRanges(MI, Entering, Internal, Exiting, hasRegMaskOp, OldIdx);
assert(!hasRegMaskOp && "Can't have RegMask operand in bundle.");
DEBUG(dbgs() << "Entering: " << Entering.size() << "\n");
DEBUG(dbgs() << "Internal: " << Internal.size() << "\n");
DEBUG(dbgs() << "Exiting: " << Exiting.size() << "\n");
moveAllEnteringFromInto(OldIdx, Entering, BR);
moveAllInternalFromInto(OldIdx, Internal, BR);
moveAllExitingFromInto(OldIdx, Exiting, BR);
#ifndef NDEBUG
LIValidator validator;
validator = std::for_each(Entering.begin(), Entering.end(), validator);
validator = std::for_each(Internal.begin(), Internal.end(), validator);
validator = std::for_each(Exiting.begin(), Exiting.end(), validator);
assert(validator.rangesOk() && "moveAllOperandsInto broke liveness.");
#endif
}
private:
#ifndef NDEBUG
class LIValidator {
private:
DenseSet<const LiveInterval*> Checked, Bogus;
public:
void operator()(const IntRangePair& P) {
const LiveInterval* LI = P.first;
if (Checked.count(LI))
return;
Checked.insert(LI);
if (LI->empty())
return;
SlotIndex LastEnd = LI->begin()->start;
for (LiveInterval::const_iterator LRI = LI->begin(), LRE = LI->end();
LRI != LRE; ++LRI) {
const LiveRange& LR = *LRI;
if (LastEnd > LR.start || LR.start >= LR.end)
Bogus.insert(LI);
LastEnd = LR.end;
}
}
bool rangesOk() const {
return Bogus.empty();
}
};
#endif
// Collect IntRangePairs for all operands of MI that may need fixing.
// Treat's MI's index as OldIdx (regardless of what it is in SlotIndexes'
// maps).
void collectRanges(MachineInstr* MI, RangeSet& Entering, RangeSet& Internal,
RangeSet& Exiting, bool& hasRegMaskOp, SlotIndex OldIdx) {
hasRegMaskOp = false;
for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
MOE = MI->operands_end();
MOI != MOE; ++MOI) {
const MachineOperand& MO = *MOI;
if (MO.isRegMask()) {
hasRegMaskOp = true;
continue;
}
if (!MO.isReg() || MO.getReg() == 0)
continue;
unsigned Reg = MO.getReg();
// TODO: Currently we're skipping uses that are reserved or have no
// interval, but we're not updating their kills. This should be
// fixed.
if (!LIS.hasInterval(Reg) ||
(TargetRegisterInfo::isPhysicalRegister(Reg) && LIS.isReserved(Reg)))
continue;
LiveInterval* LI = &LIS.getInterval(Reg);
if (MO.readsReg()) {
LiveRange* LR = LI->getLiveRangeContaining(OldIdx);
if (LR != 0)
Entering.insert(std::make_pair(LI, LR));
}
if (MO.isDef()) {
if (MO.isEarlyClobber()) {
LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getRegSlot(true));
assert(LR != 0 && "No EC range?");
if (LR->end > OldIdx.getDeadSlot())
Exiting.insert(std::make_pair(LI, LR));
else
Internal.insert(std::make_pair(LI, LR));
} else if (MO.isDead()) {
LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getRegSlot());
assert(LR != 0 && "No dead-def range?");
Internal.insert(std::make_pair(LI, LR));
} else {
LiveRange* LR = LI->getLiveRangeContaining(OldIdx.getDeadSlot());
assert(LR && LR->end > OldIdx.getDeadSlot() &&
"Non-dead-def should have live range exiting.");
Exiting.insert(std::make_pair(LI, LR));
}
}
}
}
// Collect IntRangePairs for all operands of MI that may need fixing.
void collectRangesInBundle(MachineInstr* MI, RangeSet& Entering,
RangeSet& Exiting, SlotIndex MIStartIdx,
SlotIndex MIEndIdx) {
for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
MOE = MI->operands_end();
MOI != MOE; ++MOI) {
const MachineOperand& MO = *MOI;
assert(!MO.isRegMask() && "Can't have RegMasks in bundles.");
if (!MO.isReg() || MO.getReg() == 0)
continue;
unsigned Reg = MO.getReg();
// TODO: Currently we're skipping uses that are reserved or have no
// interval, but we're not updating their kills. This should be
// fixed.
if (!LIS.hasInterval(Reg) ||
(TargetRegisterInfo::isPhysicalRegister(Reg) && LIS.isReserved(Reg)))
continue;
LiveInterval* LI = &LIS.getInterval(Reg);
if (MO.readsReg()) {
LiveRange* LR = LI->getLiveRangeContaining(MIStartIdx);
if (LR != 0)
Entering.insert(std::make_pair(LI, LR));
}
if (MO.isDef()) {
assert(!MO.isEarlyClobber() && "Early clobbers not allowed in bundles.");
assert(!MO.isDead() && "Dead-defs not allowed in bundles.");
LiveRange* LR = LI->getLiveRangeContaining(MIEndIdx.getDeadSlot());
assert(LR != 0 && "Internal ranges not allowed in bundles.");
Exiting.insert(std::make_pair(LI, LR));
}
}
}
BundleRanges createBundleRanges(RangeSet& Entering, RangeSet& Internal, RangeSet& Exiting) {
BundleRanges BR;
for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end();
EI != EE; ++EI) {
LiveInterval* LI = EI->first;
LiveRange* LR = EI->second;
BR[LI->reg].Use = LR;
}
for (RangeSet::iterator II = Internal.begin(), IE = Internal.end();
II != IE; ++II) {
LiveInterval* LI = II->first;
LiveRange* LR = II->second;
if (LR->end.isDead()) {
BR[LI->reg].Dead = LR;
} else {
BR[LI->reg].EC = LR;
}
}
for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end();
EI != EE; ++EI) {
LiveInterval* LI = EI->first;
LiveRange* LR = EI->second;
BR[LI->reg].Def = LR;
}
return BR;
}
void moveKillFlags(unsigned reg, SlotIndex OldIdx, SlotIndex newKillIdx) {
MachineInstr* OldKillMI = LIS.getInstructionFromIndex(OldIdx);
if (!OldKillMI->killsRegister(reg))
return; // Bail out if we don't have kill flags on the old register.
MachineInstr* NewKillMI = LIS.getInstructionFromIndex(newKillIdx);
assert(OldKillMI->killsRegister(reg) && "Old 'kill' instr isn't a kill.");
assert(!NewKillMI->killsRegister(reg) && "New kill instr is already a kill.");
OldKillMI->clearRegisterKills(reg, &TRI);
NewKillMI->addRegisterKilled(reg, &TRI);
}
void updateRegMaskSlots(SlotIndex OldIdx) {
SmallVectorImpl<SlotIndex>::iterator RI =
std::lower_bound(LIS.RegMaskSlots.begin(), LIS.RegMaskSlots.end(),
OldIdx);
assert(*RI == OldIdx && "No RegMask at OldIdx.");
*RI = NewIdx;
assert(*prior(RI) < *RI && *RI < *next(RI) &&
"RegSlots out of order. Did you move one call across another?");
}
// Return the last use of reg between NewIdx and OldIdx.
SlotIndex findLastUseBefore(unsigned Reg, SlotIndex OldIdx) {
SlotIndex LastUse = NewIdx;
for (MachineRegisterInfo::use_nodbg_iterator
UI = MRI.use_nodbg_begin(Reg),
UE = MRI.use_nodbg_end();
UI != UE; UI.skipInstruction()) {
const MachineInstr* MI = &*UI;
SlotIndex InstSlot = LIS.getSlotIndexes()->getInstructionIndex(MI);
if (InstSlot > LastUse && InstSlot < OldIdx)
LastUse = InstSlot;
}
return LastUse;
}
void moveEnteringUpFrom(SlotIndex OldIdx, IntRangePair& P) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
bool LiveThrough = LR->end > OldIdx.getRegSlot();
if (LiveThrough)
return;
SlotIndex LastUse = findLastUseBefore(LI->reg, OldIdx);
if (LastUse != NewIdx)
moveKillFlags(LI->reg, NewIdx, LastUse);
LR->end = LastUse.getRegSlot();
}
void moveEnteringDownFrom(SlotIndex OldIdx, IntRangePair& P) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
// Extend the LiveRange if NewIdx is past the end.
if (NewIdx > LR->end) {
// Move kill flags if OldIdx was not originally the end
// (otherwise LR->end points to an invalid slot).
if (LR->end.getRegSlot() != OldIdx.getRegSlot()) {
assert(LR->end > OldIdx && "LiveRange does not cover original slot");
moveKillFlags(LI->reg, LR->end, NewIdx);
}
LR->end = NewIdx.getRegSlot();
}
}
void moveAllEnteringFrom(SlotIndex OldIdx, RangeSet& Entering) {
bool GoingUp = NewIdx < OldIdx;
if (GoingUp) {
for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end();
EI != EE; ++EI)
moveEnteringUpFrom(OldIdx, *EI);
} else {
for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end();
EI != EE; ++EI)
moveEnteringDownFrom(OldIdx, *EI);
}
}
void moveInternalFrom(SlotIndex OldIdx, IntRangePair& P) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
assert(OldIdx < LR->start && LR->start < OldIdx.getDeadSlot() &&
LR->end <= OldIdx.getDeadSlot() &&
"Range should be internal to OldIdx.");
LiveRange Tmp(*LR);
Tmp.start = NewIdx.getRegSlot(LR->start.isEarlyClobber());
Tmp.valno->def = Tmp.start;
Tmp.end = LR->end.isDead() ? NewIdx.getDeadSlot() : NewIdx.getRegSlot();
LI->removeRange(*LR);
LI->addRange(Tmp);
}
void moveAllInternalFrom(SlotIndex OldIdx, RangeSet& Internal) {
for (RangeSet::iterator II = Internal.begin(), IE = Internal.end();
II != IE; ++II)
moveInternalFrom(OldIdx, *II);
}
void moveExitingFrom(SlotIndex OldIdx, IntRangePair& P) {
LiveRange* LR = P.second;
assert(OldIdx < LR->start && LR->start < OldIdx.getDeadSlot() &&
"Range should start in OldIdx.");
assert(LR->end > OldIdx.getDeadSlot() && "Range should exit OldIdx.");
SlotIndex NewStart = NewIdx.getRegSlot(LR->start.isEarlyClobber());
LR->start = NewStart;
LR->valno->def = NewStart;
}
void moveAllExitingFrom(SlotIndex OldIdx, RangeSet& Exiting) {
for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end();
EI != EE; ++EI)
moveExitingFrom(OldIdx, *EI);
}
void moveEnteringUpFromInto(SlotIndex OldIdx, IntRangePair& P,
BundleRanges& BR) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
bool LiveThrough = LR->end > OldIdx.getRegSlot();
if (LiveThrough) {
assert((LR->start < NewIdx || BR[LI->reg].Def == LR) &&
"Def in bundle should be def range.");
assert((BR[LI->reg].Use == 0 || BR[LI->reg].Use == LR) &&
"If bundle has use for this reg it should be LR.");
BR[LI->reg].Use = LR;
return;
}
SlotIndex LastUse = findLastUseBefore(LI->reg, OldIdx);
moveKillFlags(LI->reg, OldIdx, LastUse);
if (LR->start < NewIdx) {
// Becoming a new entering range.
assert(BR[LI->reg].Dead == 0 && BR[LI->reg].Def == 0 &&
"Bundle shouldn't be re-defining reg mid-range.");
assert((BR[LI->reg].Use == 0 || BR[LI->reg].Use == LR) &&
"Bundle shouldn't have different use range for same reg.");
LR->end = LastUse.getRegSlot();
BR[LI->reg].Use = LR;
} else {
// Becoming a new Dead-def.
assert(LR->start == NewIdx.getRegSlot(LR->start.isEarlyClobber()) &&
"Live range starting at unexpected slot.");
assert(BR[LI->reg].Def == LR && "Reg should have def range.");
assert(BR[LI->reg].Dead == 0 &&
"Can't have def and dead def of same reg in a bundle.");
LR->end = LastUse.getDeadSlot();
BR[LI->reg].Dead = BR[LI->reg].Def;
BR[LI->reg].Def = 0;
}
}
void moveEnteringDownFromInto(SlotIndex OldIdx, IntRangePair& P,
BundleRanges& BR) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
if (NewIdx > LR->end) {
// Range extended to bundle. Add to bundle uses.
// Note: Currently adds kill flags to bundle start.
assert(BR[LI->reg].Use == 0 &&
"Bundle already has use range for reg.");
moveKillFlags(LI->reg, LR->end, NewIdx);
LR->end = NewIdx.getRegSlot();
BR[LI->reg].Use = LR;
} else {
assert(BR[LI->reg].Use != 0 &&
"Bundle should already have a use range for reg.");
}
}
void moveAllEnteringFromInto(SlotIndex OldIdx, RangeSet& Entering,
BundleRanges& BR) {
bool GoingUp = NewIdx < OldIdx;
if (GoingUp) {
for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end();
EI != EE; ++EI)
moveEnteringUpFromInto(OldIdx, *EI, BR);
} else {
for (RangeSet::iterator EI = Entering.begin(), EE = Entering.end();
EI != EE; ++EI)
moveEnteringDownFromInto(OldIdx, *EI, BR);
}
}
void moveInternalFromInto(SlotIndex OldIdx, IntRangePair& P,
BundleRanges& BR) {
// TODO: Sane rules for moving ranges into bundles.
}
void moveAllInternalFromInto(SlotIndex OldIdx, RangeSet& Internal,
BundleRanges& BR) {
for (RangeSet::iterator II = Internal.begin(), IE = Internal.end();
II != IE; ++II)
moveInternalFromInto(OldIdx, *II, BR);
}
void moveExitingFromInto(SlotIndex OldIdx, IntRangePair& P,
BundleRanges& BR) {
LiveInterval* LI = P.first;
LiveRange* LR = P.second;
assert(LR->start.isRegister() &&
"Don't know how to merge exiting ECs into bundles yet.");
if (LR->end > NewIdx.getDeadSlot()) {
// This range is becoming an exiting range on the bundle.
// If there was an old dead-def of this reg, delete it.
if (BR[LI->reg].Dead != 0) {
LI->removeRange(*BR[LI->reg].Dead);
BR[LI->reg].Dead = 0;
}
assert(BR[LI->reg].Def == 0 &&
"Can't have two defs for the same variable exiting a bundle.");
LR->start = NewIdx.getRegSlot();
LR->valno->def = LR->start;
BR[LI->reg].Def = LR;
} else {
// This range is becoming internal to the bundle.
assert(LR->end == NewIdx.getRegSlot() &&
"Can't bundle def whose kill is before the bundle");
if (BR[LI->reg].Dead || BR[LI->reg].Def) {
// Already have a def for this. Just delete range.
LI->removeRange(*LR);
} else {
// Make range dead, record.
LR->end = NewIdx.getDeadSlot();
BR[LI->reg].Dead = LR;
assert(BR[LI->reg].Use == LR &&
"Range becoming dead should currently be use.");
}
// In both cases the range is no longer a use on the bundle.
BR[LI->reg].Use = 0;
}
}
void moveAllExitingFromInto(SlotIndex OldIdx, RangeSet& Exiting,
BundleRanges& BR) {
for (RangeSet::iterator EI = Exiting.begin(), EE = Exiting.end();
EI != EE; ++EI)
moveExitingFromInto(OldIdx, *EI, BR);
}
};
void LiveIntervals::handleMove(MachineInstr* MI) {
SlotIndex OldIndex = indexes_->getInstructionIndex(MI);
indexes_->removeMachineInstrFromMaps(MI);
SlotIndex NewIndex = MI->isInsideBundle() ?
indexes_->getInstructionIndex(MI) :
indexes_->insertMachineInstrInMaps(MI);
assert(getMBBStartIdx(MI->getParent()) <= OldIndex &&
OldIndex < getMBBEndIdx(MI->getParent()) &&
"Cannot handle moves across basic block boundaries.");
assert(!MI->isBundled() && "Can't handle bundled instructions yet.");
HMEditor HME(*this, *mri_, *tri_, NewIndex);
HME.moveAllRangesFrom(MI, OldIndex);
}
void LiveIntervals::handleMoveIntoBundle(MachineInstr* MI, MachineInstr* BundleStart) {
SlotIndex NewIndex = indexes_->getInstructionIndex(BundleStart);
HMEditor HME(*this, *mri_, *tri_, NewIndex);
HME.moveAllRangesInto(MI, BundleStart);
}
Reference in New Issue View Git Blame Copy Permalink