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Jakob's review of the basic register allocator.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117384 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2010-10-26 18:34:01 +00:00
parent 6915cdab8f
commit e16eecc323
4 changed files with 160 additions and 113 deletions
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30
lib/CodeGen/LiveIntervalUnion.cpp
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@ -21,6 +21,9 @@
using namespace llvm;
// Merge a LiveInterval's segments. Guarantee no overlaps.
//
// Consider coalescing adjacent segments to save space, even though it makes
// extraction more complicated.
void LiveIntervalUnion::unify(LiveInterval &lvr) {
// Add this live virtual register to the union
LiveVirtRegs::iterator pos = std::upper_bound(lvrs_.begin(), lvrs_.end(),
@ -34,19 +37,21 @@ void LiveIntervalUnion::unify(LiveInterval &lvr) {
LiveSegment segment(lvrI->start, lvrI->end, lvr);
segPos = segments_.insert(segPos, segment);
assert(*segPos == segment && "need equal val for equal key");
#ifndef NDEBUG
// check for overlap (inductively)
if (segPos != segments_.begin()) {
SegmentIter prevPos = segPos;
--prevPos;
assert(prevPos->end <= segment.start && "overlapping segments" );
}
SegmentIter nextPos = segPos;
++nextPos;
if (nextPos != segments_.end())
assert(segment.end <= nextPos->start && "overlapping segments" );
#endif // NDEBUG
}
}
namespace {
// Keep LVRs sorted for fast membership test and extraction.
struct LessReg
: public std::binary_function<LiveInterval*, LiveInterval*, bool> {
bool operator()(const LiveInterval *left, const LiveInterval *right) const {
return left->reg < right->reg;
}
};
// Low-level helper to find the first segment in the range [segI,segEnd) that
// intersects with a live virtual register segment, or segI.start >= lvr.end
//
@ -67,10 +72,8 @@ struct LessReg
// Assuming intervals are disjoint, if an intersection exists, it must be the
// segment found or immediately behind it. We continue reverse iterating to
// return the first overlap.
//
// FIXME: support extract(), handle tombstones of extracted lvrs.
typedef LiveIntervalUnion::SegmentIter SegmentIter;
SegmentIter upperBound(SegmentIter segBegin,
static SegmentIter upperBound(SegmentIter segBegin,
SegmentIter segEnd,
const LiveRange &lvrSeg) {
assert(lvrSeg.end > segBegin->start && "segment iterator precondition");
@ -84,7 +87,6 @@ SegmentIter upperBound(SegmentIter segBegin,
}
return segI;
}
} // end anonymous namespace
// Private interface accessed by Query.
//