[llvm-commits] CVS: llvm/lib/CodeGen/LiveInterval.h LiveInterval.cpp
Chris Lattner
lattner at cs.uiuc.edu
Fri Jul 23 19:52:33 PDT 2004
Changes in directory llvm/lib/CodeGen:
LiveInterval.h updated: 1.4 -> 1.5
LiveInterval.cpp updated: 1.4 -> 1.5
---
Log message:
Little stuff:
* Fix comment typeo
* add dump() methods
* add a few new methods like getLiveRangeContaining, removeRange & joinable
(which is currently the same as overlaps)
* Remove the unused operator==
Bigger change:
* In LiveInterval, instead of using a boolean isDefinedOnce to keep track of
if there are > 1 definitions in a particular interval, keep a counter,
NumValues to keep track of exactly how many there are.
* In LiveRange, add a new ValId element to indicate which of the numbered
values each LiveRange belongs to. We now no longer merge LiveRanges if
they are of differing value ID's even if they are neighbors.
---
Diffs of the changes: (+167 -27)
Index: llvm/lib/CodeGen/LiveInterval.h
diff -u llvm/lib/CodeGen/LiveInterval.h:1.4 llvm/lib/CodeGen/LiveInterval.h:1.5
--- llvm/lib/CodeGen/LiveInterval.h:1.4 Fri Jul 23 14:38:44 2004
+++ llvm/lib/CodeGen/LiveInterval.h Fri Jul 23 21:52:23 2004
@@ -10,7 +10,7 @@
// 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
@@ -31,8 +31,10 @@
/// 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");
}
@@ -48,6 +50,9 @@
bool operator==(const LiveRange &LR) const {
return start == LR.start && end == LR.end;
}
+
+ void dump() const;
+
private:
LiveRange(); // DO NOT IMPLEMENT
};
@@ -66,13 +71,16 @@
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(); }
@@ -95,6 +103,17 @@
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
@@ -104,17 +123,25 @@
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);
Index: llvm/lib/CodeGen/LiveInterval.cpp
diff -u llvm/lib/CodeGen/LiveInterval.cpp:1.4 llvm/lib/CodeGen/LiveInterval.cpp:1.5
--- llvm/lib/CodeGen/LiveInterval.cpp:1.4 Fri Jul 23 14:38:44 2004
+++ llvm/lib/CodeGen/LiveInterval.cpp Fri Jul 23 21:52:23 2004
@@ -20,7 +20,8 @@
#include "LiveInterval.h"
#include "Support/STLExtras.h"
-#include <ostream>
+#include <iostream>
+#include <map>
using namespace llvm;
// An example for liveAt():
@@ -87,17 +88,27 @@
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);
@@ -113,20 +124,23 @@
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.
@@ -148,38 +162,133 @@
// 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())
@@ -191,3 +300,7 @@
os << *i;
return os;
}
+
+void LiveInterval::dump() const {
+ std::cerr << *this << "\n";
+}
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