// 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
/// These ranges are rendered as [start,end).
struct LiveRange {
unsigned start; // Start point of the interval (inclusive)
- unsigned end; // End point of the interval (exclusive)
- LiveRange(unsigned S, unsigned E) : start(S), end(E) {
+ unsigned end; // End point of the interval (exclusive)
+ unsigned ValId; // identifier for the value contained in this interval.
+
+ LiveRange(unsigned S, unsigned E, unsigned V) : start(S), end(E), ValId(V) {
assert(S < E && "Cannot create empty or backwards range");
}
bool operator==(const LiveRange &LR) const {
return start == LR.start && end == LR.end;
}
+
+ void dump() const;
+
private:
LiveRange(); // DO NOT IMPLEMENT
};
unsigned reg; // the register of this interval
float weight; // weight of this interval
Ranges ranges; // the ranges in which this register is live
- bool isDefinedOnce; // True if this interval contains one value.
LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), weight(Weight), isDefinedOnce(false) {
+ : reg(Reg), weight(Weight), NumValues(0) {
}
- bool containsOneValue() const { return isDefinedOnce; }
+ bool containsOneValue() const { return NumValues == 1; }
+
+ unsigned getNextValue() {
+ return NumValues++;
+ }
bool empty() const { return ranges.empty(); }
bool liveAt(unsigned index) const;
+ /// getLiveRangeContaining - Return the live range that contains the
+ /// specified index, or null if there is none.
+ LiveRange *getLiveRangeContaining(unsigned Idx);
+
+
+ /// 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 joinable(const LiveInterval& other, unsigned CopyIdx) const;
+
+
bool overlaps(const LiveInterval& other) const;
/// addRange - Add the specified LiveRange to this interval, merging
addRangeFrom(LR, ranges.begin());
}
- void join(const LiveInterval& other);
+ /// 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'. This
+ /// destroys 'other'.
+ void join(LiveInterval& other, unsigned CopyIdx);
+
+
+ /// removeRange - Remove the specified range from this interval. Note that
+ /// the range must already be in this interval in its entirety.
+ void removeRange(unsigned Start, unsigned End);
bool operator<(const LiveInterval& other) const {
return start() < other.start();
}
- bool operator==(const LiveInterval& other) const {
- return reg == other.reg;
- }
+ void dump() const;
private:
+ unsigned NumValues; // the number of distinct values in this interval.
Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd);
Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr);
#include "LiveInterval.h"
#include "Support/STLExtras.h"
-#include <ostream>
+#include <iostream>
+#include <map>
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 {
+ return overlaps(other);
+}
+
+
/// 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) {
assert(I != ranges.end() && "Not a valid interval!");
+ unsigned ValId = I->ValId;
// Search for the first interval that we can't merge with.
Ranges::iterator MergeTo = next(I);
- for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo)
- /*empty*/;
+ for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
+ assert(MergeTo->ValId == ValId && "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);
LiveInterval::Ranges::iterator
LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) {
assert(I != ranges.end() && "Not a valid interval!");
+ unsigned ValId = I->ValId;
// Search for the first interval that we can't merge with.
Ranges::iterator MergeTo = I;
do {
if (MergeTo == ranges.begin()) {
I->start = NewStart;
+ ranges.erase(MergeTo, I);
return I;
}
+ assert(MergeTo->ValId == ValId && "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) {
+ if (MergeTo->end >= NewStart && MergeTo->ValId == ValId) {
MergeTo->end = I->end;
} else {
// Otherwise, extend the interval right after.
// another interval, just extend that interval to contain the range of LR.
if (it != ranges.begin()) {
Ranges::iterator B = prior(it);
- if (B->start <= Start && B->end >= Start) {
- extendIntervalEndTo(B, End);
- return B;
+ if (LR.ValId == B->ValId) {
+ 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.
+ assert(B->end <= Start &&
+ "Cannot overlap two LiveRanges with differing ValID's");
}
}
// Otherwise, if this range ends in the middle of, or right next to, another
// interval, merge it into that interval.
- if (it != ranges.end() && it->start <= End)
- return extendIntervalStartTo(it, Start);
+ if (it != ranges.end())
+ if (LR.ValId == it->ValId) {
+ if (it->start <= End) {
+ it = extendIntervalStartTo(it, Start);
+
+ // If LR is a complete superset of an interval, we may need to grow its
+ // endpoint as well.
+ if (End > it->end)
+ extendIntervalEndTo(it, End);
+ return it;
+ }
+ } else {
+ // Check to make sure that we are not overlapping two live ranges with
+ // different ValId'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);
}
-void LiveInterval::join(const LiveInterval& other) {
- isDefinedOnce &= other.isDefinedOnce;
+
+/// 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) {
+ // 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!");
+
+ // If the span we are removing is at the start of the LiveRange, adjust it.
+ if (I->start == Start) {
+ if (I->end == End)
+ ranges.erase(I); // Removed the whole LiveRange.
+ 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) {
+ I->start = Start;
+ return;
+ }
+
+ // Otherwise, we are splitting the LiveRange into two pieces.
+ unsigned 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.
+LiveRange *LiveInterval::getLiveRangeContaining(unsigned Idx) {
+ Ranges::iterator It = std::upper_bound(ranges.begin(), ranges.end(), Idx);
+ if (It != ranges.begin()) {
+ 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) {
+ LiveRange *SourceLR = Other.getLiveRangeContaining(CopyIdx-1);
+ LiveRange *DestLR = getLiveRangeContaining(CopyIdx);
+ assert(SourceLR && DestLR && "Not joining due to a copy?");
+ unsigned MergedSrcValIdx = SourceLR->ValId;
+ unsigned MergedDstValIdx = DestLR->ValId;
// Join the ranges of other into the ranges of this interval.
- Ranges::iterator cur = ranges.begin();
- for (Ranges::const_iterator i = other.ranges.begin(),
- e = other.ranges.end(); i != e; ++i)
- cur = addRangeFrom(*i, cur);
+ 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;
+ }
- weight += other.weight;
+ InsertPos = addRangeFrom(*I, InsertPos);
+ }
+
+ weight += Other.weight;
}
std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) {
- return os << "[" << LR.start << "," << LR.end << ")";
+ return os << '[' << LR.start << ',' << LR.end << ':' << LR.ValId << ")";
+}
+
+void LiveRange::dump() const {
+ std::cerr << *this << "\n";
}
+
std::ostream& llvm::operator<<(std::ostream& os, const LiveInterval& li) {
os << "%reg" << li.reg << ',' << li.weight;
if (li.empty())
os << *i;
return os;
}
+
+void LiveInterval::dump() const {
+ std::cerr << *this << "\n";
+}
// 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
/// These ranges are rendered as [start,end).
struct LiveRange {
unsigned start; // Start point of the interval (inclusive)
- unsigned end; // End point of the interval (exclusive)
- LiveRange(unsigned S, unsigned E) : start(S), end(E) {
+ unsigned end; // End point of the interval (exclusive)
+ unsigned ValId; // identifier for the value contained in this interval.
+
+ LiveRange(unsigned S, unsigned E, unsigned V) : start(S), end(E), ValId(V) {
assert(S < E && "Cannot create empty or backwards range");
}
bool operator==(const LiveRange &LR) const {
return start == LR.start && end == LR.end;
}
+
+ void dump() const;
+
private:
LiveRange(); // DO NOT IMPLEMENT
};
unsigned reg; // the register of this interval
float weight; // weight of this interval
Ranges ranges; // the ranges in which this register is live
- bool isDefinedOnce; // True if this interval contains one value.
LiveInterval(unsigned Reg, float Weight)
- : reg(Reg), weight(Weight), isDefinedOnce(false) {
+ : reg(Reg), weight(Weight), NumValues(0) {
}
- bool containsOneValue() const { return isDefinedOnce; }
+ bool containsOneValue() const { return NumValues == 1; }
+
+ unsigned getNextValue() {
+ return NumValues++;
+ }
bool empty() const { return ranges.empty(); }
bool liveAt(unsigned index) const;
+ /// getLiveRangeContaining - Return the live range that contains the
+ /// specified index, or null if there is none.
+ LiveRange *getLiveRangeContaining(unsigned Idx);
+
+
+ /// 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 joinable(const LiveInterval& other, unsigned CopyIdx) const;
+
+
bool overlaps(const LiveInterval& other) const;
/// addRange - Add the specified LiveRange to this interval, merging
addRangeFrom(LR, ranges.begin());
}
- void join(const LiveInterval& other);
+ /// 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'. This
+ /// destroys 'other'.
+ void join(LiveInterval& other, unsigned CopyIdx);
+
+
+ /// removeRange - Remove the specified range from this interval. Note that
+ /// the range must already be in this interval in its entirety.
+ void removeRange(unsigned Start, unsigned End);
bool operator<(const LiveInterval& other) const {
return start() < other.start();
}
- bool operator==(const LiveInterval& other) const {
- return reg == other.reg;
- }
+ void dump() const;
private:
+ unsigned NumValues; // the number of distinct values in this interval.
Ranges::iterator addRangeFrom(LiveRange LR, Ranges::iterator From);
void extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd);
Ranges::iterator extendIntervalStartTo(Ranges::iterator I, unsigned NewStr);
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