//
//===----------------------------------------------------------------------===//
-#include "LiveInterval.h"
+#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/Streams.h"
+#include "llvm/Target/MRegisterInfo.h"
#include <algorithm>
-#include <iostream>
#include <map>
+#include <ostream>
using namespace llvm;
// An example for liveAt():
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();
-
- 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;
- }
-
- 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;
- }
- }
- if (i->end < j->end)
- ++i;
- else
- ++j;
- }
-
- return true;
-}
-
-
/// 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
void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) {
assert(I != ranges.end() && "Not a valid interval!");
unsigned ValId = I->ValId;
+ unsigned OldEnd = I->end;
// Search for the first interval that we can't merge with.
Ranges::iterator MergeTo = next(I);
// 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
+ // Erase any dead ranges.
ranges.erase(next(I), MergeTo);
+
+ // Update kill info.
+ removeKillForValNum(ValId, OldEnd, I->end-1);
+
+ // 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 = next(I);
+ if (Next != ranges.end() && Next->start <= I->end && Next->ValId == ValId) {
+ I->end = Next->end;
+ ranges.erase(Next);
+ }
}
return MergeTo;
}
-LiveInterval::Ranges::iterator
-LiveInterval::addRangeFrom(LiveRange LR, Ranges::iterator From) {
+LiveInterval::iterator
+LiveInterval::addRangeFrom(LiveRange LR, iterator From) {
unsigned Start = LR.start, End = LR.end;
- Ranges::iterator it = std::upper_bound(From, ranges.end(), Start);
+ 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);
+ iterator B = prior(it);
if (LR.ValId == B->ValId) {
if (B->start <= Start && B->end >= Start) {
extendIntervalEndTo(B, End);
// If the span we are removing is at the start of the LiveRange, adjust it.
if (I->start == Start) {
- if (I->end == End)
+ if (I->end == End) {
+ removeKillForValNum(I->ValId, Start, End);
ranges.erase(I); // Removed the whole LiveRange.
- else
+ } else
I->start = End;
return;
}
// Otherwise if the span we are removing is at the end of the LiveRange,
// adjust the other way.
if (I->end == End) {
+ removeKillForValNum(I->ValId, Start, End);
I->end = Start;
return;
}
/// 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);
+LiveInterval::const_iterator
+LiveInterval::FindLiveRangeContaining(unsigned Idx) const {
+ const_iterator It = std::upper_bound(begin(), end(), Idx);
if (It != ranges.begin()) {
- const LiveRange &LR = *prior(It);
- if (LR.contains(Idx))
- return &LR;
+ --It;
+ if (It->contains(Idx))
+ return It;
}
- return 0;
+ return end();
}
+LiveInterval::iterator
+LiveInterval::FindLiveRangeContaining(unsigned Idx) {
+ iterator It = std::upper_bound(begin(), end(), Idx);
+ if (It != begin()) {
+ --It;
+ if (It->contains(Idx))
+ return It;
+ }
+
+ return end();
+}
-
-/// 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;
-
+/// 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, int *LHSValNoAssignments,
+ int *RHSValNoAssignments,
+ SmallVector<VNInfo, 16> &NewValueNumberInfo) {
+
// 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);
+ //
+ // Also, if one range is a physreg and one is a vreg, we always merge from the
+ // vreg into the physreg, which leaves the vreg intervals pristine.
+ if ((Other.ranges.size() > ranges.size() &&
+ MRegisterInfo::isVirtualRegister(reg)) ||
+ MRegisterInfo::isPhysicalRegister(Other.reg)) {
+ swap(Other);
+ std::swap(LHSValNoAssignments, RHSValNoAssignments);
}
- // 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;
+ // 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, e = getNumValNums(); i != e; ++i) {
+ if (ValueNumberInfo[i].def == ~1U) continue; // tombstone value #
+ if (i != (unsigned)LHSValNoAssignments[i]) {
+ MustMapCurValNos = true;
+ break;
+ }
+ }
+
+ // If we have to apply a mapping to our base interval assignment, rewrite it
+ // now.
+ if (MustMapCurValNos) {
+ // Map the first live range.
+ iterator OutIt = begin();
+ OutIt->ValId = LHSValNoAssignments[OutIt->ValId];
+ ++OutIt;
+ for (iterator I = OutIt, E = end(); I != E; ++I) {
+ OutIt->ValId = LHSValNoAssignments[I->ValId];
+
+ // 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->ValId == (OutIt-1)->ValId && (OutIt-1)->end == OutIt->start) {
+ (OutIt-1)->end = OutIt->end;
+ } else {
+ if (I != OutIt) {
+ 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.
+ ranges.erase(OutIt, end());
+ }
+ // Update val# info first. Increasing live ranges may invalidate some kills.
+ ValueNumberInfo.clear();
+ ValueNumberInfo.append(NewValueNumberInfo.begin(), NewValueNumberInfo.end());
+
+ // Okay, now insert the RHS live ranges into the LHS.
+ iterator InsertPos = begin();
+ for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) {
+ // Map the ValId in the other live range to the current live range.
+ I->ValId = RHSValNoAssignments[I->ValId];
InsertPos = addRangeFrom(*I, InsertPos);
}
weight += Other.weight;
+ if (Other.preference && !preference)
+ preference = Other.preference;
+}
+
+/// 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,
+ unsigned LHSValNo) {
+ // TODO: Make this more efficient.
+ iterator InsertPos = begin();
+ for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
+ // Map the ValId in the other live range to the current live range.
+ LiveRange Tmp = *I;
+ Tmp.ValId = LHSValNo;
+ InsertPos = addRangeFrom(Tmp, InsertPos);
+ }
+}
+
+
+/// MergeInClobberRanges - For any live ranges that are not defined in the
+/// current interval, but are defined in the Clobbers interval, mark them
+/// used with an unknown definition value.
+void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers) {
+ if (Clobbers.begin() == Clobbers.end()) return;
+
+ // Find a value # to use for the clobber ranges. If there is already a value#
+ // for unknown values, use it.
+ // FIXME: Use a single sentinal number for these!
+ unsigned ClobberValNo = getNextValue(~0U, 0);
+
+ iterator IP = begin();
+ for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) {
+ unsigned 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) {
+ 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) {
+ End = IP->start;
+ // If this trimmed away the whole range, ignore it.
+ if (Start == End) continue;
+ }
+
+ // Insert the clobber interval.
+ IP = addRangeFrom(LiveRange(Start, End, ClobberValNo), IP);
+ }
+}
+
+/// 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.
+void LiveInterval::MergeValueNumberInto(unsigned V1, unsigned 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 < V2) {
+ copyValNumInfo(V1, V2);
+ std::swap(V1, V2);
+ }
+
+ // Merge V1 live ranges into V2.
+ for (iterator I = begin(); I != end(); ) {
+ iterator LR = I++;
+ if (LR->ValId != 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->ValId == 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->ValId = 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->ValId == V2) {
+ LR->end = I->end;
+ ranges.erase(I);
+ I = LR+1;
+ }
+ }
+ }
+
+ // Now that V1 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.
+ if (V1 == getNumValNums()-1) {
+ do {
+ ValueNumberInfo.pop_back();
+ } while (ValueNumberInfo.back().def == ~1U);
+ } else {
+ ValueNumberInfo[V1].def = ~1U;
+ }
+}
+
+unsigned LiveInterval::getSize() const {
+ unsigned Sum = 0;
+ for (const_iterator I = begin(), E = end(); I != E; ++I)
+ Sum += I->end - I->start;
+ return Sum;
}
std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) {
}
void LiveRange::dump() const {
- std::cerr << *this << "\n";
+ cerr << *this << "\n";
}
-
-std::ostream& llvm::operator<<(std::ostream& os, const LiveInterval& li) {
- os << "%reg" << li.reg << ',' << li.weight;
- if (li.empty())
- return os << "EMPTY";
-
- os << " = ";
- for (LiveInterval::Ranges::const_iterator i = li.ranges.begin(),
- e = li.ranges.end(); i != e; ++i)
- os << *i;
- return os;
+void LiveInterval::print(std::ostream &OS, const MRegisterInfo *MRI) const {
+ if (MRI && MRegisterInfo::isPhysicalRegister(reg))
+ OS << MRI->getName(reg);
+ else
+ OS << "%reg" << reg;
+
+ OS << ',' << weight;
+
+ if (empty())
+ OS << "EMPTY";
+ else {
+ OS << " = ";
+ for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
+ E = ranges.end(); I != E; ++I)
+ OS << *I;
+ }
+
+ // Print value number info.
+ if (getNumValNums()) {
+ OS << " ";
+ for (unsigned i = 0; i != getNumValNums(); ++i) {
+ if (i) OS << " ";
+ OS << i << "@";
+ if (ValueNumberInfo[i].def == ~1U) {
+ OS << "x";
+ } else {
+ if (ValueNumberInfo[i].def == ~0U)
+ OS << "?";
+ else
+ OS << ValueNumberInfo[i].def;
+ unsigned e = ValueNumberInfo[i].kills.size();
+ if (e) {
+ OS << "-(";
+ for (unsigned j = 0; j != e; ++j) {
+ OS << ValueNumberInfo[i].kills[j];
+ if (j != e-1)
+ OS << " ";
+ }
+ OS << ")";
+ }
+ }
+ }
+ }
}
void LiveInterval::dump() const {
- std::cerr << *this << "\n";
+ cerr << *this << "\n";
+}
+
+
+void LiveRange::print(std::ostream &os) const {
+ os << *this;
}
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