//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/LiveInterval.h"
-#include "llvm/CodeGen/LiveIntervalAnalysis.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "RegisterCoalescer.h"
#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <algorithm>
using namespace llvm;
-// CompEnd - Compare LiveRange ends.
-namespace {
-struct CompEnd {
- bool operator()(SlotIndex A, const LiveRange &B) const {
- return A < B.end;
- }
- bool operator()(const LiveRange &A, SlotIndex B) const {
- return A.end < B;
- }
- bool operator()(const LiveRange &A, const LiveRange &B) const {
- return A.end < B.end;
- }
-};
-}
-
LiveInterval::iterator LiveInterval::find(SlotIndex Pos) {
- assert(Pos.isValid() && "Cannot search for an invalid index");
- return std::upper_bound(begin(), end(), Pos, CompEnd());
+ // This algorithm is basically std::upper_bound.
+ // Unfortunately, std::upper_bound cannot be used with mixed types until we
+ // adopt C++0x. Many libraries can do it, but not all.
+ if (empty() || Pos >= endIndex())
+ return end();
+ iterator I = begin();
+ size_t Len = ranges.size();
+ do {
+ size_t Mid = Len >> 1;
+ if (Pos < I[Mid].end)
+ Len = Mid;
+ else
+ I += Mid + 1, Len -= Mid + 1;
+ } while (Len);
+ return I;
}
-/// killedInRange - Return true if the interval has kills in [Start,End).
-bool LiveInterval::killedInRange(SlotIndex Start, SlotIndex End) const {
- Ranges::const_iterator r =
- std::lower_bound(ranges.begin(), ranges.end(), End);
-
- // Now r points to the first interval with start >= End, or ranges.end().
- if (r == ranges.begin())
- return false;
-
- --r;
- // Now r points to the last interval with end <= End.
- // r->end is the kill point.
- return r->end >= Start && r->end < End;
+VNInfo *LiveInterval::createDeadDef(SlotIndex Def,
+ VNInfo::Allocator &VNInfoAllocator) {
+ assert(!Def.isDead() && "Cannot define a value at the dead slot");
+ iterator I = find(Def);
+ if (I == end()) {
+ VNInfo *VNI = getNextValue(Def, VNInfoAllocator);
+ ranges.push_back(LiveRange(Def, Def.getDeadSlot(), VNI));
+ return VNI;
+ }
+ if (SlotIndex::isSameInstr(Def, I->start)) {
+ assert(I->valno->def == I->start && "Inconsistent existing value def");
+
+ // It is possible to have both normal and early-clobber defs of the same
+ // register on an instruction. It doesn't make a lot of sense, but it is
+ // possible to specify in inline assembly.
+ //
+ // Just convert everything to early-clobber.
+ Def = std::min(Def, I->start);
+ if (Def != I->start)
+ I->start = I->valno->def = Def;
+ return I->valno;
+ }
+ assert(SlotIndex::isEarlierInstr(Def, I->start) && "Already live at def");
+ VNInfo *VNI = getNextValue(Def, VNInfoAllocator);
+ ranges.insert(I, LiveRange(Def, Def.getDeadSlot(), VNI));
+ return VNI;
}
// overlaps - Return true if the intersection of the two live intervals is
return false;
}
+bool LiveInterval::overlaps(const LiveInterval &Other,
+ const CoalescerPair &CP,
+ const SlotIndexes &Indexes) const {
+ assert(!empty() && "empty interval");
+ if (Other.empty())
+ return false;
+
+ // Use binary searches to find initial positions.
+ const_iterator I = find(Other.beginIndex());
+ const_iterator IE = end();
+ if (I == IE)
+ return false;
+ const_iterator J = Other.find(I->start);
+ const_iterator JE = Other.end();
+ if (J == JE)
+ return false;
+
+ for (;;) {
+ // J has just been advanced to satisfy:
+ assert(J->end >= I->start);
+ // Check for an overlap.
+ if (J->start < I->end) {
+ // I and J are overlapping. Find the later start.
+ SlotIndex Def = std::max(I->start, J->start);
+ // Allow the overlap if Def is a coalescable copy.
+ if (Def.isBlock() ||
+ !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
+ return true;
+ }
+ // Advance the iterator that ends first to check for more overlaps.
+ if (J->end > I->end) {
+ std::swap(I, J);
+ std::swap(IE, JE);
+ }
+ // Advance J until J->end >= I->start.
+ do
+ if (++J == JE)
+ return false;
+ while (J->end < I->start);
+ }
+}
+
/// overlaps - Return true if the live interval overlaps a range specified
/// by [Start, End).
bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const {
valnos.pop_back();
} while (!valnos.empty() && valnos.back()->isUnused());
} else {
- ValNo->setIsUnused(true);
+ ValNo->markUnused();
}
}
/// remaining unused values.
void LiveInterval::RenumberValues(LiveIntervals &lis) {
SmallPtrSet<VNInfo*, 8> Seen;
- bool seenPHIDef = false;
valnos.clear();
for (const_iterator I = begin(), E = end(); I != E; ++I) {
VNInfo *VNI = I->valno;
assert(!VNI->isUnused() && "Unused valno used by live range");
VNI->id = (unsigned)valnos.size();
valnos.push_back(VNI);
- VNI->setHasPHIKill(false);
- if (VNI->isPHIDef())
- seenPHIDef = true;
- }
-
- // Recompute phi kill flags.
- if (!seenPHIDef)
- return;
- for (const_vni_iterator I = vni_begin(), E = vni_end(); I != E; ++I) {
- VNInfo *VNI = *I;
- if (!VNI->isPHIDef())
- continue;
- const MachineBasicBlock *PHIBB = lis.getMBBFromIndex(VNI->def);
- assert(PHIBB && "No basic block for phi-def");
- for (MachineBasicBlock::const_pred_iterator PI = PHIBB->pred_begin(),
- PE = PHIBB->pred_end(); PI != PE; ++PI) {
- VNInfo *KVNI = getVNInfoAt(lis.getMBBEndIdx(*PI).getPrevSlot());
- if (KVNI)
- KVNI->setHasPHIKill(true);
- }
}
}
// If NewEnd was in the middle of an interval, make sure to get its endpoint.
I->end = std::max(NewEnd, prior(MergeTo)->end);
- // Erase any dead ranges.
- ranges.erase(llvm::next(I), MergeTo);
-
// If the newly formed range now touches the range after it and if they have
// the same value number, merge the two ranges into one range.
- Ranges::iterator Next = llvm::next(I);
- if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) {
- I->end = Next->end;
- ranges.erase(Next);
+ if (MergeTo != ranges.end() && MergeTo->start <= I->end &&
+ MergeTo->valno == ValNo) {
+ I->end = MergeTo->end;
+ ++MergeTo;
}
+
+ // Erase any dead ranges.
+ ranges.erase(llvm::next(I), MergeTo);
}
return ranges.insert(it, LR);
}
-/// extendInBlock - If this interval is live before UseIdx in the basic
-/// block that starts at StartIdx, extend it to be live at UseIdx and return
-/// the value. If there is no live range before UseIdx, return NULL.
-VNInfo *LiveInterval::extendInBlock(SlotIndex StartIdx, SlotIndex UseIdx) {
+/// extendInBlock - If this interval is live before Kill in the basic
+/// block that starts at StartIdx, extend it to be live up to Kill and return
+/// the value. If there is no live range before Kill, return NULL.
+VNInfo *LiveInterval::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {
if (empty())
return 0;
- iterator I = std::upper_bound(begin(), end(), UseIdx);
+ iterator I = std::upper_bound(begin(), end(), Kill.getPrevSlot());
if (I == begin())
return 0;
--I;
if (I->end <= StartIdx)
return 0;
- if (I->end <= UseIdx)
- extendIntervalEndTo(I, UseIdx.getNextSlot());
+ if (I->end < Kill)
+ extendIntervalEndTo(I, Kill);
return I->valno;
}
markValNoForDeletion(ValNo);
}
-/// findDefinedVNInfo - Find the VNInfo defined by the specified
-/// index (register interval).
-VNInfo *LiveInterval::findDefinedVNInfoForRegInt(SlotIndex Idx) const {
- for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end();
- i != e; ++i) {
- if ((*i)->def == Idx)
- return *i;
- }
-
- return 0;
-}
-
/// join - Join two live intervals (this, and other) together. This applies
/// mappings to the value numbers in the LHS/RHS intervals as specified. If
/// the intervals are not joinable, this aborts.
const int *RHSValNoAssignments,
SmallVector<VNInfo*, 16> &NewVNInfo,
MachineRegisterInfo *MRI) {
+ verify();
+
// Determine if any of our live range values are mapped. This is uncommon, so
// we want to avoid the interval scan if not.
bool MustMapCurValNos = false;
for (unsigned i = 0; i != NumVals; ++i) {
unsigned LHSValID = LHSValNoAssignments[i];
if (i != LHSValID ||
- (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i)))
+ (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
MustMapCurValNos = true;
+ break;
+ }
}
// If we have to apply a mapping to our base interval assignment, rewrite it
// now.
- if (MustMapCurValNos) {
+ if (MustMapCurValNos && !empty()) {
// Map the first live range.
+
iterator OutIt = begin();
OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
- ++OutIt;
- for (iterator I = OutIt, E = end(); I != E; ++I) {
- OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+ for (iterator I = llvm::next(OutIt), E = end(); I != E; ++I) {
+ VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+ assert(nextValNo != 0 && "Huh?");
// If this live range has the same value # as its immediate predecessor,
// and if they are neighbors, remove one LiveRange. This happens when we
- // have [0,3:0)[4,7:1) and map 0/1 onto the same value #.
- if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) {
- (OutIt-1)->end = OutIt->end;
+ // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
+ if (OutIt->valno == nextValNo && OutIt->end == I->start) {
+ OutIt->end = I->end;
} else {
- if (I != OutIt) {
+ // Didn't merge. Move OutIt to the next interval,
+ ++OutIt;
+ OutIt->valno = nextValNo;
+ if (OutIt != I) {
OutIt->start = I->start;
OutIt->end = I->end;
}
-
- // Didn't merge, on to the next one.
- ++OutIt;
}
}
-
// If we merge some live ranges, chop off the end.
+ ++OutIt;
ranges.erase(OutIt, end());
}
valnos.resize(NumNewVals); // shrinkify
// Okay, now insert the RHS live ranges into the LHS.
- iterator InsertPos = begin();
unsigned RangeNo = 0;
for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) {
// Map the valno in the other live range to the current live range.
I->valno = NewVNInfo[OtherAssignments[RangeNo]];
assert(I->valno && "Adding a dead range?");
- InsertPos = addRangeFrom(*I, InsertPos);
+ }
+ mergeIntervalRanges(Other);
+
+ verify();
+}
+
+/// \brief Helper function for merging in another LiveInterval's ranges.
+///
+/// This is a helper routine implementing an efficient merge of another
+/// LiveIntervals ranges into the current interval.
+///
+/// \param LHSValNo If non-NULL, set as the new value number for every range
+/// from RHS which is merged into the LHS.
+/// \param RHSValNo If non-NULL, then only ranges in RHS whose original value
+/// number maches this value number will be merged into LHS.
+void LiveInterval::mergeIntervalRanges(const LiveInterval &RHS,
+ VNInfo *LHSValNo,
+ const VNInfo *RHSValNo) {
+ if (RHS.empty())
+ return;
+
+ // Ensure we're starting with a valid range. Note that we don't verify RHS
+ // because it may have had its value numbers adjusted in preparation for
+ // merging.
+ verify();
+
+ // The strategy for merging these efficiently is as follows:
+ //
+ // 1) Find the beginning of the impacted ranges in the LHS.
+ // 2) Create a new, merged sub-squence of ranges merging from the position in
+ // #1 until either LHS or RHS is exhausted. Any part of LHS between RHS
+ // entries being merged will be copied into this new range.
+ // 3) Replace the relevant section in LHS with these newly merged ranges.
+ // 4) Append any remaning ranges from RHS if LHS is exhausted in #2.
+ //
+ // We don't follow the typical in-place merge strategy for sorted ranges of
+ // appending the new ranges to the back and then using std::inplace_merge
+ // because one step of the merge can both mutate the original elements and
+ // remove elements from the original. Essentially, because the merge includes
+ // collapsing overlapping ranges, a more complex approach is required.
+
+ // We do an initial binary search to optimize for a common pattern: a large
+ // LHS, and a very small RHS.
+ const_iterator RI = RHS.begin(), RE = RHS.end();
+ iterator LE = end(), LI = std::upper_bound(begin(), LE, *RI);
+
+ // Merge into NewRanges until one of the ranges is exhausted.
+ SmallVector<LiveRange, 4> NewRanges;
+
+ // Keep track of where to begin the replacement.
+ iterator ReplaceI = LI;
+
+ // If there are preceding ranges in the LHS, put the last one into NewRanges
+ // so we can optionally extend it. Adjust the replacement point accordingly.
+ if (LI != begin()) {
+ ReplaceI = llvm::prior(LI);
+ NewRanges.push_back(*ReplaceI);
+ }
+
+ // Now loop over the mergable portions of both LHS and RHS, merging into
+ // NewRanges.
+ while (LI != LE && RI != RE) {
+ // Skip incoming ranges with the wrong value.
+ if (RHSValNo && RI->valno != RHSValNo) {
+ ++RI;
+ continue;
+ }
+
+ // Select the first range. We pick the earliest start point, and then the
+ // largest range.
+ LiveRange R = *LI;
+ if (*RI < R) {
+ R = *RI;
+ ++RI;
+ if (LHSValNo)
+ R.valno = LHSValNo;
+ } else {
+ ++LI;
+ }
+
+ if (NewRanges.empty()) {
+ NewRanges.push_back(R);
+ continue;
+ }
+
+ LiveRange &LastR = NewRanges.back();
+ if (R.valno == LastR.valno) {
+ // Try to merge this range into the last one.
+ if (R.start <= LastR.end) {
+ LastR.end = std::max(LastR.end, R.end);
+ continue;
+ }
+ } else {
+ // We can't merge ranges across a value number.
+ assert(R.start >= LastR.end &&
+ "Cannot overlap two LiveRanges with differing ValID's");
+ }
+
+ // If all else fails, just append the range.
+ NewRanges.push_back(R);
+ }
+ assert(RI == RE || LI == LE);
+
+ // Check for being able to merge into the trailing sequence of ranges on the LHS.
+ if (!NewRanges.empty())
+ for (; LI != LE && (LI->valno == NewRanges.back().valno &&
+ LI->start <= NewRanges.back().end);
+ ++LI)
+ NewRanges.back().end = std::max(NewRanges.back().end, LI->end);
+
+ // Replace the ranges in the LHS with the newly merged ones. It would be
+ // really nice if there were a move-supporting 'replace' directly in
+ // SmallVector, but as there is not, we pay the price of copies to avoid
+ // wasted memory allocations.
+ SmallVectorImpl<LiveRange>::iterator NRI = NewRanges.begin(),
+ NRE = NewRanges.end();
+ for (; ReplaceI != LI && NRI != NRE; ++ReplaceI, ++NRI)
+ *ReplaceI = *NRI;
+ if (NRI == NRE)
+ ranges.erase(ReplaceI, LI);
+ else
+ ranges.insert(LI, NRI, NRE);
+
+ // And finally insert any trailing end of RHS (if we have one).
+ for (; RI != RE; ++RI) {
+ LiveRange R = *RI;
+ if (LHSValNo)
+ R.valno = LHSValNo;
+ if (!ranges.empty() &&
+ ranges.back().valno == R.valno && R.start <= ranges.back().end)
+ ranges.back().end = std::max(ranges.back().end, R.end);
+ else
+ ranges.push_back(R);
}
- ComputeJoinedWeight(Other);
+ // Ensure we finished with a valid new sequence of ranges.
+ verify();
}
/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live
/// the overlapping LiveRanges have the specified value number.
void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS,
VNInfo *LHSValNo) {
- // TODO: Make this more efficient.
- iterator InsertPos = begin();
- for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
- // Map the valno in the other live range to the current live range.
- LiveRange Tmp = *I;
- Tmp.valno = LHSValNo;
- InsertPos = addRangeFrom(Tmp, InsertPos);
- }
+ mergeIntervalRanges(RHS, LHSValNo);
}
-
/// MergeValueInAsValue - Merge all of the live ranges of a specific val#
/// in RHS into this live interval as the specified value number.
/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
/// current interval, it will replace the value numbers of the overlaped
/// live ranges with the specified value number.
-void LiveInterval::MergeValueInAsValue(
- const LiveInterval &RHS,
- const VNInfo *RHSValNo, VNInfo *LHSValNo) {
- SmallVector<VNInfo*, 4> ReplacedValNos;
- iterator IP = begin();
- for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
- assert(I->valno == RHS.getValNumInfo(I->valno->id) && "Bad VNInfo");
- if (I->valno != RHSValNo)
- continue;
- SlotIndex Start = I->start, End = I->end;
- IP = std::upper_bound(IP, end(), Start);
- // If the start of this range overlaps with an existing liverange, trim it.
- if (IP != begin() && IP[-1].end > Start) {
- if (IP[-1].valno != LHSValNo) {
- ReplacedValNos.push_back(IP[-1].valno);
- IP[-1].valno = LHSValNo; // Update val#.
- }
- Start = IP[-1].end;
- // Trimmed away the whole range?
- if (Start >= End) continue;
- }
- // If the end of this range overlaps with an existing liverange, trim it.
- if (IP != end() && End > IP->start) {
- if (IP->valno != LHSValNo) {
- ReplacedValNos.push_back(IP->valno);
- IP->valno = LHSValNo; // Update val#.
- }
- End = IP->start;
- // If this trimmed away the whole range, ignore it.
- if (Start == End) continue;
- }
-
- // Map the valno in the other live range to the current live range.
- IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP);
- }
-
-
- SmallSet<VNInfo*, 4> Seen;
- for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) {
- VNInfo *V1 = ReplacedValNos[i];
- if (Seen.insert(V1)) {
- bool isDead = true;
- for (const_iterator I = begin(), E = end(); I != E; ++I)
- if (I->valno == V1) {
- isDead = false;
- break;
- }
- if (isDead) {
- // Now that V1 is dead, remove it.
- markValNoForDeletion(V1);
- }
- }
- }
+void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS,
+ const VNInfo *RHSValNo,
+ VNInfo *LHSValNo) {
+ mergeIntervalRanges(RHS, LHSValNo, RHSValNo);
}
-
-
/// MergeValueNumberInto - This method is called when two value nubmers
/// are found to be equivalent. This eliminates V1, replacing all
/// LiveRanges with the V1 value number with the V2 value number. This can
}
}
- // Merge the relevant flags.
- V2->mergeFlags(V1);
-
// Now that V1 is dead, remove it.
markValNoForDeletion(V1);
return V2;
}
-void LiveInterval::Copy(const LiveInterval &RHS,
- MachineRegisterInfo *MRI,
- VNInfo::Allocator &VNInfoAllocator) {
- ranges.clear();
- valnos.clear();
- std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(RHS.reg);
- MRI->setRegAllocationHint(reg, Hint.first, Hint.second);
-
- weight = RHS.weight;
- for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) {
- const VNInfo *VNI = RHS.getValNumInfo(i);
- createValueCopy(VNI, VNInfoAllocator);
- }
- for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) {
- const LiveRange &LR = RHS.ranges[i];
- addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id)));
- }
-}
-
unsigned LiveInterval::getSize() const {
unsigned Sum = 0;
for (const_iterator I = begin(), E = end(); I != E; ++I)
return Sum;
}
-/// ComputeJoinedWeight - Set the weight of a live interval Joined
-/// after Other has been merged into it.
-void LiveInterval::ComputeJoinedWeight(const LiveInterval &Other) {
- // If either of these intervals was spilled, the weight is the
- // weight of the non-spilled interval. This can only happen with
- // iterative coalescers.
-
- if (Other.weight != HUGE_VALF) {
- weight += Other.weight;
- }
- else if (weight == HUGE_VALF &&
- !TargetRegisterInfo::isPhysicalRegister(reg)) {
- // Remove this assert if you have an iterative coalescer
- assert(0 && "Joining to spilled interval");
- weight = Other.weight;
- }
- else {
- // Otherwise the weight stays the same
- // Remove this assert if you have an iterative coalescer
- assert(0 && "Joining from spilled interval");
- }
-}
-
raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) {
return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")";
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void LiveRange::dump() const {
dbgs() << *this << "\n";
}
+#endif
-void LiveInterval::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const {
- OS << PrintReg(reg, TRI);
- if (weight != 0)
- OS << ',' << weight;
-
+void LiveInterval::print(raw_ostream &OS) const {
if (empty())
- OS << " EMPTY";
+ OS << "EMPTY";
else {
- OS << " = ";
for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
E = ranges.end(); I != E; ++I) {
OS << *I;
} else {
OS << vni->def;
if (vni->isPHIDef())
- OS << "-phidef";
- if (vni->hasPHIKill())
- OS << "-phikill";
- if (vni->hasRedefByEC())
- OS << "-ec";
+ OS << "-phi";
}
}
}
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void LiveInterval::dump() const {
dbgs() << *this << "\n";
}
+#endif
+
+#ifndef NDEBUG
+void LiveInterval::verify() const {
+ for (const_iterator I = begin(), E = end(); I != E; ++I) {
+ assert(I->start.isValid());
+ assert(I->end.isValid());
+ assert(I->start < I->end);
+ assert(I->valno != 0);
+ assert(I->valno == valnos[I->valno->id]);
+ if (llvm::next(I) != E) {
+ assert(I->end <= llvm::next(I)->start);
+ if (I->end == llvm::next(I)->start)
+ assert(I->valno != llvm::next(I)->valno);
+ }
+ }
+}
+#endif
void LiveRange::print(raw_ostream &os) const {
os << *this;
}
+//===----------------------------------------------------------------------===//
+// LiveRangeUpdater class
+//===----------------------------------------------------------------------===//
+//
+// The LiveRangeUpdater class always maintains these invariants:
+//
+// - When LastStart is invalid, Spills is empty and the iterators are invalid.
+// This is the initial state, and the state created by flush().
+// In this state, isDirty() returns false.
+//
+// Otherwise, segments are kept in three separate areas:
+//
+// 1. [begin; WriteI) at the front of LI.
+// 2. [ReadI; end) at the back of LI.
+// 3. Spills.
+//
+// - LI.begin() <= WriteI <= ReadI <= LI.end().
+// - Segments in all three areas are fully ordered and coalesced.
+// - Segments in area 1 precede and can't coalesce with segments in area 2.
+// - Segments in Spills precede and can't coalesce with segments in area 2.
+// - No coalescing is possible between segments in Spills and segments in area
+// 1, and there are no overlapping segments.
+//
+// The segments in Spills are not ordered with respect to the segments in area
+// 1. They need to be merged.
+//
+// When they exist, Spills.back().start <= LastStart,
+// and WriteI[-1].start <= LastStart.
+
+void LiveRangeUpdater::print(raw_ostream &OS) const {
+ if (!isDirty()) {
+ if (LI)
+ OS << "Clean " << PrintReg(LI->reg) << " updater: " << *LI << '\n';
+ else
+ OS << "Null updater.\n";
+ return;
+ }
+ assert(LI && "Can't have null LI in dirty updater.");
+ OS << PrintReg(LI->reg) << " updater with gap = " << (ReadI - WriteI)
+ << ", last start = " << LastStart
+ << ":\n Area 1:";
+ for (LiveInterval::const_iterator I = LI->begin(); I != WriteI; ++I)
+ OS << ' ' << *I;
+ OS << "\n Spills:";
+ for (unsigned I = 0, E = Spills.size(); I != E; ++I)
+ OS << ' ' << Spills[I];
+ OS << "\n Area 2:";
+ for (LiveInterval::const_iterator I = ReadI, E = LI->end(); I != E; ++I)
+ OS << ' ' << *I;
+ OS << '\n';
+}
+
+void LiveRangeUpdater::dump() const
+{
+ print(errs());
+}
+
+// Determine if A and B should be coalesced.
+static inline bool coalescable(const LiveRange &A, const LiveRange &B) {
+ assert(A.start <= B.start && "Unordered live ranges.");
+ if (A.end == B.start)
+ return A.valno == B.valno;
+ if (A.end < B.start)
+ return false;
+ assert(A.valno == B.valno && "Cannot overlap different values");
+ return true;
+}
+
+void LiveRangeUpdater::add(LiveRange Seg) {
+ assert(LI && "Cannot add to a null destination");
+
+ // Flush the state if Start moves backwards.
+ if (!LastStart.isValid() || LastStart > Seg.start) {
+ if (isDirty())
+ flush();
+ // This brings us to an uninitialized state. Reinitialize.
+ assert(Spills.empty() && "Leftover spilled segments");
+ WriteI = ReadI = LI->begin();
+ }
+
+ // Remember start for next time.
+ LastStart = Seg.start;
+
+ // Advance ReadI until it ends after Seg.start.
+ LiveInterval::iterator E = LI->end();
+ if (ReadI != E && ReadI->end <= Seg.start) {
+ // First try to close the gap between WriteI and ReadI with spills.
+ if (ReadI != WriteI)
+ mergeSpills();
+ // Then advance ReadI.
+ if (ReadI == WriteI)
+ ReadI = WriteI = LI->find(Seg.start);
+ else
+ while (ReadI != E && ReadI->end <= Seg.start)
+ *WriteI++ = *ReadI++;
+ }
+
+ assert(ReadI == E || ReadI->end > Seg.start);
+
+ // Check if the ReadI segment begins early.
+ if (ReadI != E && ReadI->start <= Seg.start) {
+ assert(ReadI->valno == Seg.valno && "Cannot overlap different values");
+ // Bail if Seg is completely contained in ReadI.
+ if (ReadI->end >= Seg.end)
+ return;
+ // Coalesce into Seg.
+ Seg.start = ReadI->start;
+ ++ReadI;
+ }
+
+ // Coalesce as much as possible from ReadI into Seg.
+ while (ReadI != E && coalescable(Seg, *ReadI)) {
+ Seg.end = std::max(Seg.end, ReadI->end);
+ ++ReadI;
+ }
+
+ // Try coalescing Spills.back() into Seg.
+ if (!Spills.empty() && coalescable(Spills.back(), Seg)) {
+ Seg.start = Spills.back().start;
+ Seg.end = std::max(Spills.back().end, Seg.end);
+ Spills.pop_back();
+ }
+
+ // Try coalescing Seg into WriteI[-1].
+ if (WriteI != LI->begin() && coalescable(WriteI[-1], Seg)) {
+ WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);
+ return;
+ }
+
+ // Seg doesn't coalesce with anything, and needs to be inserted somewhere.
+ if (WriteI != ReadI) {
+ *WriteI++ = Seg;
+ return;
+ }
+
+ // Finally, append to LI or Spills.
+ if (WriteI == E) {
+ LI->ranges.push_back(Seg);
+ WriteI = ReadI = LI->ranges.end();
+ } else
+ Spills.push_back(Seg);
+}
+
+// Merge as many spilled segments as possible into the gap between WriteI
+// and ReadI. Advance WriteI to reflect the inserted instructions.
+void LiveRangeUpdater::mergeSpills() {
+ // Perform a backwards merge of Spills and [SpillI;WriteI).
+ size_t GapSize = ReadI - WriteI;
+ size_t NumMoved = std::min(Spills.size(), GapSize);
+ LiveInterval::iterator Src = WriteI;
+ LiveInterval::iterator Dst = Src + NumMoved;
+ LiveInterval::iterator SpillSrc = Spills.end();
+ LiveInterval::iterator B = LI->begin();
+
+ // This is the new WriteI position after merging spills.
+ WriteI = Dst;
+
+ // Now merge Src and Spills backwards.
+ while (Src != Dst) {
+ if (Src != B && Src[-1].start > SpillSrc[-1].start)
+ *--Dst = *--Src;
+ else
+ *--Dst = *--SpillSrc;
+ }
+ assert(NumMoved == size_t(Spills.end() - SpillSrc));
+ Spills.erase(SpillSrc, Spills.end());
+}
+
+void LiveRangeUpdater::flush() {
+ if (!isDirty())
+ return;
+ // Clear the dirty state.
+ LastStart = SlotIndex();
+
+ assert(LI && "Cannot add to a null destination");
+
+ // Nothing to merge?
+ if (Spills.empty()) {
+ LI->ranges.erase(WriteI, ReadI);
+ LI->verify();
+ return;
+ }
+
+ // Resize the WriteI - ReadI gap to match Spills.
+ size_t GapSize = ReadI - WriteI;
+ if (GapSize < Spills.size()) {
+ // The gap is too small. Make some room.
+ size_t WritePos = WriteI - LI->begin();
+ LI->ranges.insert(ReadI, Spills.size() - GapSize, LiveRange());
+ // This also invalidated ReadI, but it is recomputed below.
+ WriteI = LI->ranges.begin() + WritePos;
+ } else {
+ // Shrink the gap if necessary.
+ LI->ranges.erase(WriteI + Spills.size(), ReadI);
+ }
+ ReadI = WriteI + Spills.size();
+ mergeSpills();
+ LI->verify();
+}
+
unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) {
// Create initial equivalence classes.
- eqClass_.clear();
- eqClass_.grow(LI->getNumValNums());
+ EqClass.clear();
+ EqClass.grow(LI->getNumValNums());
const VNInfo *used = 0, *unused = 0;
// Group all unused values into one class.
if (VNI->isUnused()) {
if (unused)
- eqClass_.join(unused->id, VNI->id);
+ EqClass.join(unused->id, VNI->id);
unused = VNI;
continue;
}
used = VNI;
if (VNI->isPHIDef()) {
- const MachineBasicBlock *MBB = lis_.getMBBFromIndex(VNI->def);
+ const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
assert(MBB && "Phi-def has no defining MBB");
// Connect to values live out of predecessors.
for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI)
- if (const VNInfo *PVNI =
- LI->getVNInfoAt(lis_.getMBBEndIdx(*PI).getPrevSlot()))
- eqClass_.join(VNI->id, PVNI->id);
+ if (const VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
+ EqClass.join(VNI->id, PVNI->id);
} else {
// Normal value defined by an instruction. Check for two-addr redef.
// FIXME: This could be coincidental. Should we really check for a tied
// operand constraint?
// Note that VNI->def may be a use slot for an early clobber def.
- if (const VNInfo *UVNI = LI->getVNInfoAt(VNI->def.getPrevSlot()))
- eqClass_.join(VNI->id, UVNI->id);
+ if (const VNInfo *UVNI = LI->getVNInfoBefore(VNI->def))
+ EqClass.join(VNI->id, UVNI->id);
}
}
// Lump all the unused values in with the last used value.
if (used && unused)
- eqClass_.join(used->id, unused->id);
+ EqClass.join(used->id, unused->id);
- eqClass_.compress();
- return eqClass_.getNumClasses();
+ EqClass.compress();
+ return EqClass.getNumClasses();
}
-void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[]) {
+void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[],
+ MachineRegisterInfo &MRI) {
assert(LIV[0] && "LIV[0] must be set");
LiveInterval &LI = *LIV[0];
- // First move runs to new intervals.
+ // Rewrite instructions.
+ for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LI.reg),
+ RE = MRI.reg_end(); RI != RE;) {
+ MachineOperand &MO = RI.getOperand();
+ MachineInstr *MI = MO.getParent();
+ ++RI;
+ // DBG_VALUE instructions should have been eliminated earlier.
+ LiveRangeQuery LRQ(LI, LIS.getInstructionIndex(MI));
+ const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
+ // In the case of an <undef> use that isn't tied to any def, VNI will be
+ // NULL. If the use is tied to a def, VNI will be the defined value.
+ if (!VNI)
+ continue;
+ MO.setReg(LIV[getEqClass(VNI)]->reg);
+ }
+
+ // Move runs to new intervals.
LiveInterval::iterator J = LI.begin(), E = LI.end();
- while (J != E && eqClass_[J->valno->id] == 0)
+ while (J != E && EqClass[J->valno->id] == 0)
++J;
for (LiveInterval::iterator I = J; I != E; ++I) {
- if (unsigned eq = eqClass_[I->valno->id]) {
+ if (unsigned eq = EqClass[I->valno->id]) {
assert((LIV[eq]->empty() || LIV[eq]->expiredAt(I->start)) &&
"New intervals should be empty");
LIV[eq]->ranges.push_back(*I);
// Transfer VNInfos to their new owners and renumber them.
unsigned j = 0, e = LI.getNumValNums();
- while (j != e && eqClass_[j] == 0)
+ while (j != e && EqClass[j] == 0)
++j;
for (unsigned i = j; i != e; ++i) {
VNInfo *VNI = LI.getValNumInfo(i);
- if (unsigned eq = eqClass_[i]) {
+ if (unsigned eq = EqClass[i]) {
VNI->id = LIV[eq]->getNumValNums();
LIV[eq]->valnos.push_back(VNI);
} else {
projects / oota-llvm.git / blobdiff