//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the LiveRange and LiveInterval classes. Given some
// numbering of each the machine instructions an interval [i, j) is said to be a
// live interval for register v if there is no instruction with number j' > j
-// such that v is live at j' abd there is no instruction with number i' < i such
+// such that v is live at j' and there is no instruction with number i' < i such
// that v is live at i'. In this implementation intervals can have holes,
// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each
// individual range is represented as an instance of LiveRange, and the whole
//
//===----------------------------------------------------------------------===//
-#include "LiveInterval.h"
+#include "llvm/CodeGen/LiveInterval.h"
+#include "RegisterCoalescer.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
-#include "llvm/Target/MRegisterInfo.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>
-#include <iostream>
-#include <map>
using namespace llvm;
-// An example for liveAt():
-//
-// this = [1,4), liveAt(0) will return false. The instruction defining this
-// spans slots [0,3]. The interval belongs to an spilled definition of the
-// variable it represents. This is because slot 1 is used (def slot) and spans
-// up to slot 3 (store slot).
-//
-bool LiveInterval::liveAt(unsigned I) const {
- Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I);
-
- if (r == ranges.begin())
- return false;
+LiveInterval::iterator LiveInterval::find(SlotIndex Pos) {
+ // 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;
+}
- --r;
- return r->contains(I);
+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
//
bool LiveInterval::overlapsFrom(const LiveInterval& other,
const_iterator StartPos) const {
+ assert(!empty() && "empty interval");
const_iterator i = begin();
const_iterator ie = end();
const_iterator j = StartPos;
return false;
}
-/// joinable - Two intervals are joinable if the either don't overlap at all
-/// or if the destination of the copy is a single assignment value, and it
-/// only overlaps with one value in the source interval.
-bool LiveInterval::joinable(const LiveInterval &other, unsigned CopyIdx) const {
- const LiveRange *SourceLR = other.getLiveRangeContaining(CopyIdx-1);
- const LiveRange *DestLR = getLiveRangeContaining(CopyIdx);
- assert(SourceLR && DestLR && "Not joining due to a copy?");
- unsigned OtherValIdx = SourceLR->ValId;
- unsigned ThisValIdx = DestLR->ValId;
-
- Ranges::const_iterator i = ranges.begin();
- Ranges::const_iterator ie = ranges.end();
- Ranges::const_iterator j = other.ranges.begin();
- Ranges::const_iterator je = other.ranges.end();
+bool LiveInterval::overlaps(const LiveInterval &Other,
+ const CoalescerPair &CP,
+ const SlotIndexes &Indexes) const {
+ assert(!empty() && "empty interval");
+ if (Other.empty())
+ return false;
- if (i->start < j->start) {
- i = std::upper_bound(i, ie, j->start);
- if (i != ranges.begin()) --i;
- } else if (j->start < i->start) {
- j = std::upper_bound(j, je, i->start);
- if (j != other.ranges.begin()) --j;
- }
+ // 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;
- while (i != ie && j != je) {
- if (i->start == j->start) {
- // If this is not the allowed value merge, we cannot join.
- if (i->ValId != ThisValIdx || j->ValId != OtherValIdx)
- return false;
- } else if (i->start < j->start) {
- if (i->end > j->start) {
- if (i->ValId != ThisValIdx || j->ValId != OtherValIdx)
- return false;
- }
- } else {
- if (j->end > i->start) {
- if (i->ValId != ThisValIdx || j->ValId != OtherValIdx)
- 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;
}
- if (i->end < j->end)
- ++i;
- else
- ++j;
+ // 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);
}
+}
- return true;
+/// overlaps - Return true if the live interval overlaps a range specified
+/// by [Start, End).
+bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const {
+ assert(Start < End && "Invalid range");
+ const_iterator I = std::lower_bound(begin(), end(), End);
+ return I != begin() && (--I)->end > Start;
+}
+
+
+/// ValNo is dead, remove it. If it is the largest value number, just nuke it
+/// (and any other deleted values neighboring it), otherwise mark it as ~1U so
+/// it can be nuked later.
+void LiveInterval::markValNoForDeletion(VNInfo *ValNo) {
+ if (ValNo->id == getNumValNums()-1) {
+ do {
+ valnos.pop_back();
+ } while (!valnos.empty() && valnos.back()->isUnused());
+ } else {
+ ValNo->markUnused();
+ }
}
+/// RenumberValues - Renumber all values in order of appearance and delete the
+/// remaining unused values.
+void LiveInterval::RenumberValues(LiveIntervals &lis) {
+ SmallPtrSet<VNInfo*, 8> Seen;
+ valnos.clear();
+ for (const_iterator I = begin(), E = end(); I != E; ++I) {
+ VNInfo *VNI = I->valno;
+ if (!Seen.insert(VNI))
+ continue;
+ assert(!VNI->isUnused() && "Unused valno used by live range");
+ VNI->id = (unsigned)valnos.size();
+ valnos.push_back(VNI);
+ }
+}
/// extendIntervalEndTo - This method is used when we want to extend the range
/// specified by I to end at the specified endpoint. To do this, we should
/// merge and eliminate all ranges that this will overlap with. The iterator is
/// not invalidated.
-void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) {
+void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) {
assert(I != ranges.end() && "Not a valid interval!");
- unsigned ValId = I->ValId;
+ VNInfo *ValNo = I->valno;
// Search for the first interval that we can't merge with.
- Ranges::iterator MergeTo = next(I);
+ Ranges::iterator MergeTo = llvm::next(I);
for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
- assert(MergeTo->ValId == ValId && "Cannot merge with differing values!");
+ assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
}
// 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(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.
+ 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);
}
/// specified by I to start at the specified endpoint. To do this, we should
/// merge and eliminate all ranges that this will overlap with.
LiveInterval::Ranges::iterator
-LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) {
+LiveInterval::extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStart) {
assert(I != ranges.end() && "Not a valid interval!");
- unsigned ValId = I->ValId;
+ VNInfo *ValNo = I->valno;
// Search for the first interval that we can't merge with.
Ranges::iterator MergeTo = I;
ranges.erase(MergeTo, I);
return I;
}
- assert(MergeTo->ValId == ValId && "Cannot merge with differing values!");
+ assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
--MergeTo;
} while (NewStart <= MergeTo->start);
// If we start in the middle of another interval, just delete a range and
// extend that interval.
- if (MergeTo->end >= NewStart && MergeTo->ValId == ValId) {
+ if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
MergeTo->end = I->end;
} else {
// Otherwise, extend the interval right after.
MergeTo->end = I->end;
}
- ranges.erase(next(MergeTo), next(I));
+ ranges.erase(llvm::next(MergeTo), llvm::next(I));
return MergeTo;
}
-LiveInterval::Ranges::iterator
-LiveInterval::addRangeFrom(LiveRange LR, Ranges::iterator From) {
- unsigned Start = LR.start, End = LR.end;
- Ranges::iterator it = std::upper_bound(From, ranges.end(), Start);
+LiveInterval::iterator
+LiveInterval::addRangeFrom(LiveRange LR, iterator From) {
+ SlotIndex Start = LR.start, End = LR.end;
+ iterator it = std::upper_bound(From, ranges.end(), Start);
// If the inserted interval starts in the middle or right at the end of
// another interval, just extend that interval to contain the range of LR.
if (it != ranges.begin()) {
- Ranges::iterator B = prior(it);
- if (LR.ValId == B->ValId) {
+ iterator B = prior(it);
+ if (LR.valno == B->valno) {
if (B->start <= Start && B->end >= Start) {
extendIntervalEndTo(B, End);
return B;
}
} else {
// Check to make sure that we are not overlapping two live ranges with
- // different ValId's.
+ // different valno's.
assert(B->end <= Start &&
"Cannot overlap two LiveRanges with differing ValID's"
" (did you def the same reg twice in a MachineInstr?)");
// Otherwise, if this range ends in the middle of, or right next to, another
// interval, merge it into that interval.
- if (it != ranges.end())
- if (LR.ValId == it->ValId) {
+ if (it != ranges.end()) {
+ if (LR.valno == it->valno) {
if (it->start <= End) {
it = extendIntervalStartTo(it, Start);
}
} else {
// Check to make sure that we are not overlapping two live ranges with
- // different ValId's.
+ // different valno's.
assert(it->start >= End &&
"Cannot overlap two LiveRanges with differing ValID's");
}
+ }
// Otherwise, this is just a new range that doesn't interact with anything.
// Insert it.
return ranges.insert(it, LR);
}
+/// 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(), Kill.getPrevSlot());
+ if (I == begin())
+ return 0;
+ --I;
+ if (I->end <= StartIdx)
+ return 0;
+ if (I->end < Kill)
+ extendIntervalEndTo(I, Kill);
+ return I->valno;
+}
/// removeRange - Remove the specified range from this interval. Note that
-/// the range must already be in this interval in its entirety.
-void LiveInterval::removeRange(unsigned Start, unsigned End) {
+/// the range must be in a single LiveRange in its entirety.
+void LiveInterval::removeRange(SlotIndex Start, SlotIndex End,
+ bool RemoveDeadValNo) {
// Find the LiveRange containing this span.
- Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start);
- assert(I != ranges.begin() && "Range is not in interval!");
- --I;
- assert(I->contains(Start) && I->contains(End-1) &&
- "Range is not entirely in interval!");
+ Ranges::iterator I = find(Start);
+ assert(I != ranges.end() && "Range is not in interval!");
+ assert(I->containsRange(Start, End) && "Range is not entirely in interval!");
// If the span we are removing is at the start of the LiveRange, adjust it.
+ VNInfo *ValNo = I->valno;
if (I->start == Start) {
- if (I->end == End)
+ if (I->end == End) {
+ if (RemoveDeadValNo) {
+ // Check if val# is dead.
+ bool isDead = true;
+ for (const_iterator II = begin(), EE = end(); II != EE; ++II)
+ if (II != I && II->valno == ValNo) {
+ isDead = false;
+ break;
+ }
+ if (isDead) {
+ // Now that ValNo is dead, remove it.
+ markValNoForDeletion(ValNo);
+ }
+ }
+
ranges.erase(I); // Removed the whole LiveRange.
- else
+ } else
I->start = End;
return;
}
}
// Otherwise, we are splitting the LiveRange into two pieces.
- unsigned OldEnd = I->end;
+ SlotIndex OldEnd = I->end;
I->end = Start; // Trim the old interval.
// Insert the new one.
- ranges.insert(next(I), LiveRange(End, OldEnd, I->ValId));
-}
-
-/// getLiveRangeContaining - Return the live range that contains the
-/// specified index, or null if there is none.
-const LiveRange *LiveInterval::getLiveRangeContaining(unsigned Idx) const {
- Ranges::const_iterator It = std::upper_bound(ranges.begin(),ranges.end(),Idx);
- if (It != ranges.begin()) {
- const LiveRange &LR = *prior(It);
- if (LR.contains(Idx))
- return &LR;
- }
-
- return 0;
-}
-
-
-
-/// join - Join two live intervals (this, and other) together. This operation
-/// is the result of a copy instruction in the source program, that occurs at
-/// index 'CopyIdx' that copies from 'Other' to 'this'.
-void LiveInterval::join(LiveInterval &Other, unsigned CopyIdx) {
- const LiveRange *SourceLR = Other.getLiveRangeContaining(CopyIdx-1);
- const LiveRange *DestLR = getLiveRangeContaining(CopyIdx);
- assert(SourceLR && DestLR && "Not joining due to a copy?");
- unsigned MergedSrcValIdx = SourceLR->ValId;
- unsigned MergedDstValIdx = DestLR->ValId;
-
- // Try to do the least amount of work possible. In particular, if there are
- // more liverange chunks in the other set than there are in the 'this' set,
- // swap sets to merge the fewest chunks in possible.
- if (Other.ranges.size() > ranges.size()) {
- std::swap(MergedSrcValIdx, MergedDstValIdx);
- std::swap(ranges, Other.ranges);
- std::swap(NumValues, Other.NumValues);
- }
-
- // Join the ranges of other into the ranges of this interval.
- Ranges::iterator InsertPos = ranges.begin();
- std::map<unsigned, unsigned> Dst2SrcIdxMap;
- for (Ranges::iterator I = Other.ranges.begin(),
- E = Other.ranges.end(); I != E; ++I) {
- // Map the ValId in the other live range to the current live range.
- if (I->ValId == MergedSrcValIdx)
- I->ValId = MergedDstValIdx;
- else {
- unsigned &NV = Dst2SrcIdxMap[I->ValId];
- if (NV == 0) NV = getNextValue();
- I->ValId = NV;
+ ranges.insert(llvm::next(I), LiveRange(End, OldEnd, ValNo));
+}
+
+/// removeValNo - Remove all the ranges defined by the specified value#.
+/// Also remove the value# from value# list.
+void LiveInterval::removeValNo(VNInfo *ValNo) {
+ if (empty()) return;
+ Ranges::iterator I = ranges.end();
+ Ranges::iterator E = ranges.begin();
+ do {
+ --I;
+ if (I->valno == ValNo)
+ ranges.erase(I);
+ } while (I != E);
+ // Now that ValNo is dead, remove it.
+ markValNoForDeletion(ValNo);
+}
+
+/// 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.
+void LiveInterval::join(LiveInterval &Other,
+ const int *LHSValNoAssignments,
+ 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;
+ unsigned NumVals = getNumValNums();
+ unsigned NumNewVals = NewVNInfo.size();
+ for (unsigned i = 0; i != NumVals; ++i) {
+ unsigned LHSValID = LHSValNoAssignments[i];
+ if (i != LHSValID ||
+ (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 && !empty()) {
+ // Map the first live range.
+
+ iterator OutIt = begin();
+ OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->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 [0,4:0)[4,7:1) and map 0/1 onto the same value #.
+ if (OutIt->valno == nextValNo && OutIt->end == I->start) {
+ OutIt->end = I->end;
+ } else {
+ // Didn't merge. Move OutIt to the next interval,
+ ++OutIt;
+ OutIt->valno = nextValNo;
+ if (OutIt != I) {
+ OutIt->start = I->start;
+ OutIt->end = I->end;
+ }
+ }
}
+ // If we merge some live ranges, chop off the end.
+ ++OutIt;
+ ranges.erase(OutIt, end());
+ }
- InsertPos = addRangeFrom(*I, InsertPos);
+ // Rewrite Other values before changing the VNInfo ids.
+ // This can leave Other in an invalid state because we're not coalescing
+ // touching segments that now have identical values. That's OK since Other is
+ // not supposed to be valid after calling join();
+ for (iterator I = Other.begin(), E = Other.end(); I != E; ++I)
+ I->valno = NewVNInfo[RHSValNoAssignments[I->valno->id]];
+
+ // Update val# info. Renumber them and make sure they all belong to this
+ // LiveInterval now. Also remove dead val#'s.
+ unsigned NumValNos = 0;
+ for (unsigned i = 0; i < NumNewVals; ++i) {
+ VNInfo *VNI = NewVNInfo[i];
+ if (VNI) {
+ if (NumValNos >= NumVals)
+ valnos.push_back(VNI);
+ else
+ valnos[NumValNos] = VNI;
+ VNI->id = NumValNos++; // Renumber val#.
+ }
}
+ if (NumNewVals < NumVals)
+ valnos.resize(NumNewVals); // shrinkify
- weight += Other.weight;
+ // Okay, now insert the RHS live ranges into the LHS.
+ LiveRangeUpdater Updater(this);
+ for (iterator I = Other.begin(), E = Other.end(); I != E; ++I)
+ Updater.add(*I);
}
-std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) {
- return os << '[' << LR.start << ',' << LR.end << ':' << LR.ValId << ")";
+/// MergeRangesInAsValue - Merge all of the intervals 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, but only if
+/// the overlapping LiveRanges have the specified value number.
+void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS,
+ VNInfo *LHSValNo) {
+ LiveRangeUpdater Updater(this);
+ for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I)
+ Updater.add(I->start, I->end, LHSValNo);
}
-void LiveRange::dump() const {
- std::cerr << *this << "\n";
+/// 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) {
+ LiveRangeUpdater Updater(this);
+ for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I)
+ if (I->valno == RHSValNo)
+ Updater.add(I->start, I->end, LHSValNo);
}
-void LiveInterval::print(std::ostream &OS, const MRegisterInfo *MRI) const {
- if (MRI && MRegisterInfo::isPhysicalRegister(reg))
- OS << MRI->getName(reg);
- else
- OS << "%reg" << reg;
+/// 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
+/// cause merging of V1/V2 values numbers and compaction of the value space.
+VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
+ assert(V1 != V2 && "Identical value#'s are always equivalent!");
+
+ // This code actually merges the (numerically) larger value number into the
+ // smaller value number, which is likely to allow us to compactify the value
+ // space. The only thing we have to be careful of is to preserve the
+ // instruction that defines the result value.
+
+ // Make sure V2 is smaller than V1.
+ if (V1->id < V2->id) {
+ V1->copyFrom(*V2);
+ std::swap(V1, V2);
+ }
- OS << ',' << weight;
+ // Merge V1 live ranges into V2.
+ for (iterator I = begin(); I != end(); ) {
+ iterator LR = I++;
+ if (LR->valno != V1) continue; // Not a V1 LiveRange.
+
+ // Okay, we found a V1 live range. If it had a previous, touching, V2 live
+ // range, extend it.
+ if (LR != begin()) {
+ iterator Prev = LR-1;
+ if (Prev->valno == V2 && Prev->end == LR->start) {
+ Prev->end = LR->end;
+
+ // Erase this live-range.
+ ranges.erase(LR);
+ I = Prev+1;
+ LR = Prev;
+ }
+ }
+
+ // Okay, now we have a V1 or V2 live range that is maximally merged forward.
+ // Ensure that it is a V2 live-range.
+ LR->valno = V2;
+
+ // If we can merge it into later V2 live ranges, do so now. We ignore any
+ // following V1 live ranges, as they will be merged in subsequent iterations
+ // of the loop.
+ if (I != end()) {
+ if (I->start == LR->end && I->valno == V2) {
+ LR->end = I->end;
+ ranges.erase(I);
+ I = LR+1;
+ }
+ }
+ }
+
+ // Now that V1 is dead, remove it.
+ markValNoForDeletion(V1);
+
+ return V2;
+}
+
+unsigned LiveInterval::getSize() const {
+ unsigned Sum = 0;
+ for (const_iterator I = begin(), E = end(); I != E; ++I)
+ Sum += I->start.distance(I->end);
+ return Sum;
+}
+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 {
if (empty())
OS << "EMPTY";
else {
- OS << " = ";
for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
- E = ranges.end(); I != E; ++I)
- OS << *I;
+ E = ranges.end(); I != E; ++I) {
+ OS << *I;
+ assert(I->valno == getValNumInfo(I->valno->id) && "Bad VNInfo");
+ }
+ }
+
+ // Print value number info.
+ if (getNumValNums()) {
+ OS << " ";
+ unsigned vnum = 0;
+ for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
+ ++i, ++vnum) {
+ const VNInfo *vni = *i;
+ if (vnum) OS << " ";
+ OS << vnum << "@";
+ if (vni->isUnused()) {
+ OS << "x";
+ } else {
+ OS << vni->def;
+ if (vni->isPHIDef())
+ OS << "-phi";
+ }
+ }
}
}
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void LiveInterval::dump() const {
- std::cerr << *this << "\n";
+ 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());
+
+ const VNInfo *used = 0, *unused = 0;
+
+ // Determine connections.
+ for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end();
+ I != E; ++I) {
+ const VNInfo *VNI = *I;
+ // Group all unused values into one class.
+ if (VNI->isUnused()) {
+ if (unused)
+ EqClass.join(unused->id, VNI->id);
+ unused = VNI;
+ continue;
+ }
+ used = VNI;
+ if (VNI->isPHIDef()) {
+ 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->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->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.compress();
+ return EqClass.getNumClasses();
+}
+
+void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[],
+ MachineRegisterInfo &MRI) {
+ assert(LIV[0] && "LIV[0] must be set");
+ LiveInterval &LI = *LIV[0];
+
+ // 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)
+ ++J;
+ for (LiveInterval::iterator I = J; I != E; ++I) {
+ 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);
+ } else
+ *J++ = *I;
+ }
+ LI.ranges.erase(J, E);
+
+ // Transfer VNInfos to their new owners and renumber them.
+ unsigned j = 0, e = LI.getNumValNums();
+ while (j != e && EqClass[j] == 0)
+ ++j;
+ for (unsigned i = j; i != e; ++i) {
+ VNInfo *VNI = LI.getValNumInfo(i);
+ if (unsigned eq = EqClass[i]) {
+ VNI->id = LIV[eq]->getNumValNums();
+ LIV[eq]->valnos.push_back(VNI);
+ } else {
+ VNI->id = j;
+ LI.valnos[j++] = VNI;
+ }
+ }
+ LI.valnos.resize(j);
}
projects / oota-llvm.git / blobdiff