//
// 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
+// live range for register v if there is no instruction with number j' >= j
// 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
-// interval is represented as an instance of LiveInterval.
+// that v is live at i'. In this implementation ranges can have holes,
+// i.e. a range might look like [1,20), [50,65), [1000,1001). Each
+// individual segment is represented as an instance of LiveRange::Segment,
+// and the whole range is represented as an instance of LiveRange.
//
//===----------------------------------------------------------------------===//
#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 "RegisterCoalescer.h"
#include <algorithm>
using namespace llvm;
-LiveInterval::iterator LiveInterval::find(SlotIndex Pos) {
+LiveRange::iterator LiveRange::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();
+ size_t Len = size();
do {
size_t Mid = Len >> 1;
if (Pos < I[Mid].end)
return I;
}
-VNInfo *LiveInterval::createDeadDef(SlotIndex Def,
- VNInfo::Allocator &VNInfoAllocator) {
+VNInfo *LiveRange::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));
+ segments.push_back(Segment(Def, Def.getDeadSlot(), VNI));
return VNI;
}
if (SlotIndex::isSameInstr(Def, I->start)) {
- assert(I->start == Def && "Cannot insert def, already live");
- assert(I->valno->def == Def && "Inconsistent existing value def");
+ 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));
+ segments.insert(I, Segment(Def, Def.getDeadSlot(), VNI));
return VNI;
}
-// overlaps - Return true if the intersection of the two live intervals is
+// overlaps - Return true if the intersection of the two live ranges is
// not empty.
//
// An example for overlaps():
// 4: B = ...
// 8: C = A + B ;; last use of A
//
-// The live intervals should look like:
+// The live ranges should look like:
//
// A = [3, 11)
// B = [7, x)
// A->overlaps(C) should return false since we want to be able to join
// A and C.
//
-bool LiveInterval::overlapsFrom(const LiveInterval& other,
- const_iterator StartPos) const {
- assert(!empty() && "empty interval");
+bool LiveRange::overlapsFrom(const LiveRange& other,
+ const_iterator StartPos) const {
+ assert(!empty() && "empty range");
const_iterator i = begin();
const_iterator ie = end();
const_iterator j = StartPos;
if (i->start < j->start) {
i = std::upper_bound(i, ie, j->start);
- if (i != ranges.begin()) --i;
+ if (i != begin()) --i;
} else if (j->start < i->start) {
++StartPos;
if (StartPos != other.end() && StartPos->start <= i->start) {
assert(StartPos < other.end() && i < end());
j = std::upper_bound(j, je, i->start);
- if (j != other.ranges.begin()) --j;
+ if (j != other.begin()) --j;
}
} else {
return true;
return false;
}
-bool LiveInterval::overlaps(const LiveInterval &Other,
- const CoalescerPair &CP,
- const SlotIndexes &Indexes) const {
- assert(!empty() && "empty interval");
+bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,
+ const SlotIndexes &Indexes) const {
+ assert(!empty() && "empty range");
if (Other.empty())
return false;
}
}
-/// overlaps - Return true if the live interval overlaps a range specified
+/// overlaps - Return true if the live range overlaps an interval specified
/// by [Start, End).
-bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const {
+bool LiveRange::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) {
+void LiveRange::markValNoForDeletion(VNInfo *ValNo) {
if (ValNo->id == getNumValNums()-1) {
do {
valnos.pop_back();
/// RenumberValues - Renumber all values in order of appearance and delete the
/// remaining unused values.
-void LiveInterval::RenumberValues(LiveIntervals &lis) {
+void LiveRange::RenumberValues() {
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");
+ assert(!VNI->isUnused() && "Unused valno used by live segment");
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, SlotIndex NewEnd) {
- assert(I != ranges.end() && "Not a valid interval!");
+/// This method is used when we want to extend the segment specified by I to end
+/// at the specified endpoint. To do this, we should merge and eliminate all
+/// segments that this will overlap with. The iterator is not invalidated.
+void LiveRange::extendSegmentEndTo(iterator I, SlotIndex NewEnd) {
+ assert(I != end() && "Not a valid segment!");
VNInfo *ValNo = I->valno;
- // Search for the first interval that we can't merge with.
- Ranges::iterator MergeTo = llvm::next(I);
- for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
+ // Search for the first segment that we can't merge with.
+ iterator MergeTo = llvm::next(I);
+ for (; MergeTo != end() && NewEnd >= MergeTo->end; ++MergeTo) {
assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
}
- // If NewEnd was in the middle of an interval, make sure to get its endpoint.
+ // If NewEnd was in the middle of a segment, make sure to get its endpoint.
I->end = std::max(NewEnd, prior(MergeTo)->end);
- // 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 &&
+ // If the newly formed segment now touches the segment after it and if they
+ // have the same value number, merge the two segments into one segment.
+ if (MergeTo != end() && MergeTo->start <= I->end &&
MergeTo->valno == ValNo) {
I->end = MergeTo->end;
++MergeTo;
}
- // Erase any dead ranges.
- ranges.erase(llvm::next(I), MergeTo);
+ // Erase any dead segments.
+ segments.erase(llvm::next(I), MergeTo);
}
-/// extendIntervalStartTo - This method is used when we want to extend the range
-/// 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, SlotIndex NewStart) {
- assert(I != ranges.end() && "Not a valid interval!");
+/// This method is used when we want to extend the segment specified by I to
+/// start at the specified endpoint. To do this, we should merge and eliminate
+/// all segments that this will overlap with.
+LiveRange::iterator
+LiveRange::extendSegmentStartTo(iterator I, SlotIndex NewStart) {
+ assert(I != end() && "Not a valid segment!");
VNInfo *ValNo = I->valno;
- // Search for the first interval that we can't merge with.
- Ranges::iterator MergeTo = I;
+ // Search for the first segment that we can't merge with.
+ iterator MergeTo = I;
do {
- if (MergeTo == ranges.begin()) {
+ if (MergeTo == begin()) {
I->start = NewStart;
- ranges.erase(MergeTo, I);
+ segments.erase(MergeTo, I);
return I;
}
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 we start in the middle of another segment, just delete a range and
+ // extend that segment.
if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
MergeTo->end = I->end;
} else {
- // Otherwise, extend the interval right after.
+ // Otherwise, extend the segment right after.
++MergeTo;
MergeTo->start = NewStart;
MergeTo->end = I->end;
}
- ranges.erase(llvm::next(MergeTo), llvm::next(I));
+ segments.erase(llvm::next(MergeTo), llvm::next(I));
return MergeTo;
}
-LiveInterval::iterator
-LiveInterval::addRangeFrom(LiveRange LR, iterator From) {
- SlotIndex Start = LR.start, End = LR.end;
- iterator it = std::upper_bound(From, ranges.end(), Start);
+LiveRange::iterator LiveRange::addSegmentFrom(Segment S, iterator From) {
+ SlotIndex Start = S.start, End = S.end;
+ iterator it = std::upper_bound(From, 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()) {
+ // If the inserted segment starts in the middle or right at the end of
+ // another segment, just extend that segment to contain the segment of S.
+ if (it != begin()) {
iterator B = prior(it);
- if (LR.valno == B->valno) {
+ if (S.valno == B->valno) {
if (B->start <= Start && B->end >= Start) {
- extendIntervalEndTo(B, End);
+ extendSegmentEndTo(B, End);
return B;
}
} else {
- // Check to make sure that we are not overlapping two live ranges with
+ // Check to make sure that we are not overlapping two live segments with
// different valno's.
assert(B->end <= Start &&
- "Cannot overlap two LiveRanges with differing ValID's"
+ "Cannot overlap two segments 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.valno == it->valno) {
+ // Otherwise, if this segment ends in the middle of, or right next to, another
+ // segment, merge it into that segment.
+ if (it != end()) {
+ if (S.valno == it->valno) {
if (it->start <= End) {
- it = extendIntervalStartTo(it, Start);
+ it = extendSegmentStartTo(it, Start);
- // If LR is a complete superset of an interval, we may need to grow its
+ // If S is a complete superset of a segment, we may need to grow its
// endpoint as well.
if (End > it->end)
- extendIntervalEndTo(it, End);
+ extendSegmentEndTo(it, End);
return it;
}
} else {
- // Check to make sure that we are not overlapping two live ranges with
+ // Check to make sure that we are not overlapping two live segments with
// different valno's.
assert(it->start >= End &&
- "Cannot overlap two LiveRanges with differing ValID's");
+ "Cannot overlap two segments with differing ValID's");
}
}
- // Otherwise, this is just a new range that doesn't interact with anything.
+ // Otherwise, this is just a new segment that doesn't interact with anything.
// Insert it.
- return ranges.insert(it, LR);
+ return segments.insert(it, S);
}
-/// extendInBlock - If this interval is live before Kill in the basic
+/// extendInBlock - If this range 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) {
+VNInfo *LiveRange::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {
if (empty())
return 0;
iterator I = std::upper_bound(begin(), end(), Kill.getPrevSlot());
if (I->end <= StartIdx)
return 0;
if (I->end < Kill)
- extendIntervalEndTo(I, Kill);
+ extendSegmentEndTo(I, Kill);
return I->valno;
}
-/// removeRange - Remove the specified range from this interval. Note that
-/// 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 = 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.
+/// Remove the specified segment from this range. Note that the segment must
+/// be in a single Segment in its entirety.
+void LiveRange::removeSegment(SlotIndex Start, SlotIndex End,
+ bool RemoveDeadValNo) {
+ // Find the Segment containing this span.
+ iterator I = find(Start);
+ assert(I != end() && "Segment is not in range!");
+ assert(I->containsInterval(Start, End)
+ && "Segment is not entirely in range!");
+
+ // If the span we are removing is at the start of the Segment, adjust it.
VNInfo *ValNo = I->valno;
if (I->start == Start) {
if (I->end == End) {
}
}
- ranges.erase(I); // Removed the whole LiveRange.
+ segments.erase(I); // Removed the whole Segment.
} else
I->start = End;
return;
}
- // Otherwise if the span we are removing is at the end of the LiveRange,
+ // Otherwise if the span we are removing is at the end of the Segment,
// adjust the other way.
if (I->end == End) {
I->end = Start;
return;
}
- // Otherwise, we are splitting the LiveRange into two pieces.
+ // Otherwise, we are splitting the Segment into two pieces.
SlotIndex OldEnd = I->end;
- I->end = Start; // Trim the old interval.
+ I->end = Start; // Trim the old segment.
// Insert the new one.
- ranges.insert(llvm::next(I), LiveRange(End, OldEnd, ValNo));
+ segments.insert(llvm::next(I), Segment(End, OldEnd, ValNo));
}
-/// removeValNo - Remove all the ranges defined by the specified value#.
+/// removeValNo - Remove all the segments defined by the specified value#.
/// Also remove the value# from value# list.
-void LiveInterval::removeValNo(VNInfo *ValNo) {
+void LiveRange::removeValNo(VNInfo *ValNo) {
if (empty()) return;
- Ranges::iterator I = ranges.end();
- Ranges::iterator E = ranges.begin();
+ iterator I = end();
+ iterator E = begin();
do {
--I;
if (I->valno == ValNo)
- ranges.erase(I);
+ segments.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) {
+void LiveRange::join(LiveRange &Other,
+ const int *LHSValNoAssignments,
+ const int *RHSValNoAssignments,
+ SmallVectorImpl<VNInfo *> &NewVNInfo) {
verify();
- // Determine if any of our live range values are mapped. This is uncommon, so
- // we want to avoid the interval scan if not.
+ // Determine if any of our values are mapped. This is uncommon, so we want
+ // to avoid the range scan if not.
bool MustMapCurValNos = false;
unsigned NumVals = getNumValNums();
unsigned NumNewVals = NewVNInfo.size();
}
}
- // If we have to apply a mapping to our base interval assignment, rewrite it
- // now.
- if (MustMapCurValNos) {
+ // If we have to apply a mapping to our base range 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 = next(OutIt), E = end(); I != E; ++I) {
+ 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
+ // and if they are neighbors, remove one Segment. 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,
+ // Didn't merge. Move OutIt to the next segment,
++OutIt;
OutIt->valno = nextValNo;
if (OutIt != I) {
}
}
}
- // If we merge some live ranges, chop off the end.
+ // If we merge some segments, chop off the end.
++OutIt;
- ranges.erase(OutIt, end());
+ segments.erase(OutIt, end());
}
- // Remember assignements because val# ids are changing.
- SmallVector<unsigned, 16> OtherAssignments;
+ // 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)
- OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]);
+ 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.
+ // LiveRange now. Also remove dead val#'s.
unsigned NumValNos = 0;
for (unsigned i = 0; i < NumNewVals; ++i) {
VNInfo *VNI = NewVNInfo[i];
if (NumNewVals < NumVals)
valnos.resize(NumNewVals); // shrinkify
- // Okay, now insert the RHS live ranges into the LHS.
- 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?");
- }
- 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);
- }
-
- // Ensure we finished with a valid new sequence of ranges.
- verify();
+ // Okay, now insert the RHS live segments into the LHS.
+ LiveRangeUpdater Updater(this);
+ for (iterator I = Other.begin(), E = Other.end(); I != E; ++I)
+ Updater.add(*I);
}
-/// 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) {
- mergeIntervalRanges(RHS, LHSValNo);
+/// Merge all of the segments in RHS into this live range as the specified
+/// value number. The segments in RHS are allowed to overlap with segments in
+/// the current range, but only if the overlapping segments have the
+/// specified value number.
+void LiveRange::MergeSegmentsInAsValue(const LiveRange &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);
}
-/// 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) {
- mergeIntervalRanges(RHS, LHSValNo, RHSValNo);
+/// MergeValueInAsValue - Merge all of the live segments of a specific val#
+/// in RHS into this live range as the specified value number.
+/// The segments in RHS are allowed to overlap with segments in the
+/// current range, it will replace the value numbers of the overlaped
+/// segments with the specified value number.
+void LiveRange::MergeValueInAsValue(const LiveRange &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);
}
/// 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
+/// segments 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) {
+VNInfo *LiveRange::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
std::swap(V1, V2);
}
- // Merge V1 live ranges into V2.
+ // Merge V1 segments into V2.
for (iterator I = begin(); I != end(); ) {
- iterator LR = I++;
- if (LR->valno != V1) continue; // Not a V1 LiveRange.
+ iterator S = I++;
+ if (S->valno != V1) continue; // Not a V1 Segment.
// 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;
+ if (S != begin()) {
+ iterator Prev = S-1;
+ if (Prev->valno == V2 && Prev->end == S->start) {
+ Prev->end = S->end;
// Erase this live-range.
- ranges.erase(LR);
+ segments.erase(S);
I = Prev+1;
- LR = Prev;
+ S = 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;
+ S->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
+ // If we can merge it into later V2 segments, do so now. We ignore any
+ // following V1 segments, 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;
+ if (I->start == S->end && I->valno == V2) {
+ S->end = I->end;
+ segments.erase(I);
+ I = S+1;
}
}
}
return Sum;
}
-raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) {
- return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")";
+raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange::Segment &S) {
+ return os << '[' << S.start << ',' << S.end << ':' << S.valno->id << ")";
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void LiveRange::dump() const {
+void LiveRange::Segment::dump() const {
dbgs() << *this << "\n";
}
#endif
-void LiveInterval::print(raw_ostream &OS) const {
+void LiveRange::print(raw_ostream &OS) const {
if (empty())
OS << "EMPTY";
else {
- for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
- E = ranges.end(); I != E; ++I) {
+ for (const_iterator I = begin(), E = end(); I != E; ++I) {
OS << *I;
assert(I->valno == getValNumInfo(I->valno->id) && "Bad VNInfo");
}
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
-void LiveInterval::dump() const {
+void LiveRange::dump() const {
dbgs() << *this << "\n";
}
#endif
#ifndef NDEBUG
-void LiveInterval::verify() const {
+void LiveRange::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->id < valnos.size());
assert(I->valno == valnos[I->valno->id]);
if (llvm::next(I) != E) {
assert(I->end <= llvm::next(I)->start);
#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 LR.
+// 2. [ReadI; end) at the back of LR.
+// 3. Spills.
+//
+// - LR.begin() <= WriteI <= ReadI <= LR.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 (LR)
+ OS << "Clean updater: " << *LR << '\n';
+ else
+ OS << "Null updater.\n";
+ return;
+ }
+ assert(LR && "Can't have null LR in dirty updater.");
+ OS << " updater with gap = " << (ReadI - WriteI)
+ << ", last start = " << LastStart
+ << ":\n Area 1:";
+ for (LiveRange::const_iterator I = LR->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 (LiveRange::const_iterator I = ReadI, E = LR->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::Segment &A,
+ const LiveRange::Segment &B) {
+ assert(A.start <= B.start && "Unordered live segments.");
+ 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::Segment Seg) {
+ assert(LR && "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 = LR->begin();
+ }
+
+ // Remember start for next time.
+ LastStart = Seg.start;
+
+ // Advance ReadI until it ends after Seg.start.
+ LiveRange::iterator E = LR->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 = LR->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 != LR->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 LR or Spills.
+ if (WriteI == E) {
+ LR->segments.push_back(Seg);
+ WriteI = ReadI = LR->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);
+ LiveRange::iterator Src = WriteI;
+ LiveRange::iterator Dst = Src + NumMoved;
+ LiveRange::iterator SpillSrc = Spills.end();
+ LiveRange::iterator B = LR->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(LR && "Cannot add to a null destination");
+
+ // Nothing to merge?
+ if (Spills.empty()) {
+ LR->segments.erase(WriteI, ReadI);
+ LR->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 - LR->begin();
+ LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());
+ // This also invalidated ReadI, but it is recomputed below.
+ WriteI = LR->begin() + WritePos;
+ } else {
+ // Shrink the gap if necessary.
+ LR->segments.erase(WriteI + Spills.size(), ReadI);
+ }
+ ReadI = WriteI + Spills.size();
+ mergeSpills();
+ LR->verify();
}
unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) {
MachineOperand &MO = RI.getOperand();
MachineInstr *MI = MO.getParent();
++RI;
- // DBG_VALUE instructions should have been eliminated earlier.
- LiveRangeQuery LRQ(LI, LIS.getInstructionIndex(MI));
+ // DBG_VALUE instructions don't have slot indexes, so get the index of the
+ // instruction before them.
+ // Normally, DBG_VALUE instructions are removed before this function is
+ // called, but it is not a requirement.
+ SlotIndex Idx;
+ if (MI->isDebugValue())
+ Idx = LIS.getSlotIndexes()->getIndexBefore(MI);
+ else
+ Idx = LIS.getInstructionIndex(MI);
+ LiveRangeQuery LRQ(LI, Idx);
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 (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);
+ LIV[eq]->segments.push_back(*I);
} else
*J++ = *I;
}
- LI.ranges.erase(J, E);
+ LI.segments.erase(J, E);
// Transfer VNInfos to their new owners and renumber them.
unsigned j = 0, e = LI.getNumValNums();
projects / oota-llvm.git / blobdiff