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Stop precomputing last split points, query the SplitAnalysis cache on demand. 

llvm-svn: 128875
This commit is contained in:
Jakob Stoklund Olesen 2011-04-05 04:20:29 +00:00
parent 50b2db8a02
commit d93b0e3ced
3 changed files with 17 additions and 21 deletions
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23
llvm/lib/CodeGen/RegAllocGreedy.cpp
View File

@ -445,7 +445,7 @@ float RAGreedy::calcSplitConstraints(unsigned PhysReg) {
// Interference for the live-out value.
if (BI.LiveOut) {
if (Intf.last() >= BI.LastSplitPoint)
if (Intf.last() >= SA->getLastSplitPoint(BC.Number))
BC.Exit = SpillPlacement::MustSpill, Ins += BI.Uses;
else if (!BI.Uses)
BC.Exit = SpillPlacement::PrefSpill;
@ -530,9 +530,9 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
Intf.moveToBlock(BI.MBB->getNumber());
DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " -> EB#"
<< Bundles->getBundle(BI.MBB->getNumber(), 1)
<< " [" << Start << ';' << BI.LastSplitPoint << '-'
<< Stop << ") intf [" << Intf.first() << ';' << Intf.last()
<< ')');
<< " [" << Start << ';'
<< SA->getLastSplitPoint(BI.MBB->getNumber()) << '-' << Stop
<< ") intf [" << Intf.first() << ';' << Intf.last() << ')');
// The interference interval should either be invalid or overlap MBB.
assert((!Intf.hasInterference() || Intf.first() < Stop)
@ -588,6 +588,7 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
continue;
}
SlotIndex LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
if (Intf.last().getBoundaryIndex() < BI.LastUse) {
// There are interference-free uses at the end of the block.
// Find the first use that can get the live-out register.
@ -598,11 +599,11 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
SlotIndex Use = *UI;
assert(Use <= BI.LastUse && "Couldn't find last use");
// Only attempt a split befroe the last split point.
if (Use.getBaseIndex() <= BI.LastSplitPoint) {
if (Use.getBaseIndex() <= LastSplitPoint) {
DEBUG(dbgs() << ", free use at " << Use << ".\n");
SlotIndex SegStart = SE->enterIntvBefore(Use);
assert(SegStart >= Intf.last() && "Couldn't avoid interference");
assert(SegStart < BI.LastSplitPoint && "Impossible split point");
assert(SegStart < LastSplitPoint && "Impossible split point");
SE->useIntv(SegStart, Stop);
continue;
}
@ -630,7 +631,8 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
Intf.moveToBlock(BI.MBB->getNumber());
DEBUG(dbgs() << "EB#" << Bundles->getBundle(BI.MBB->getNumber(), 0)
<< " -> BB#" << BI.MBB->getNumber() << " [" << Start << ';'
<< BI.LastSplitPoint << '-' << Stop << ')');
<< SA->getLastSplitPoint(BI.MBB->getNumber()) << '-' << Stop
<< ')');
// Check interference entering the block.
if (!Intf.hasInterference()) {
@ -654,9 +656,10 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
continue;
}
if (!RegOut) {
SlotIndex LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
// Block is live-through, but exit bundle is on the stack.
// Spill immediately after the last use.
if (BI.LastUse < BI.LastSplitPoint) {
if (BI.LastUse < LastSplitPoint) {
DEBUG(dbgs() << ", uses, stack-out.\n");
SE->useIntv(Start, SE->leaveIntvAfter(BI.LastUse));
continue;
@ -664,8 +667,8 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
// The last use is after the last split point, it is probably an
// indirect jump.
DEBUG(dbgs() << ", uses at " << BI.LastUse << " after split point "
<< BI.LastSplitPoint << ", stack-out.\n");
SlotIndex SegEnd = SE->leaveIntvBefore(BI.LastSplitPoint);
<< LastSplitPoint << ", stack-out.\n");
SlotIndex SegEnd = SE->leaveIntvBefore(LastSplitPoint);
SE->useIntv(Start, SegEnd);
// Run a double interval from the split to the last use.
// This makes it possible to spill the complement without affecting the

13
llvm/lib/CodeGen/SplitKit.cpp
View File

@ -151,12 +151,6 @@ bool SplitAnalysis::calcLiveBlockInfo() {
SlotIndex Start, Stop;
tie(Start, Stop) = LIS.getSlotIndexes()->getMBBRange(BI.MBB);
// The last split point is the latest possible insertion point that dominates
// all successor blocks. If interference reaches LastSplitPoint, it is not
// possible to insert a split or reload that makes CurLI live in the
// outgoing bundle.
BI.LastSplitPoint = getLastSplitPoint(BI.MBB->getNumber());
// LVI is the first live segment overlapping MBB.
BI.LiveIn = LVI->start <= Start;
if (!BI.LiveIn)
@ -947,13 +941,14 @@ void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
continue;
openIntv();
SlotIndex LastSplitPoint = SA.getLastSplitPoint(BI.MBB->getNumber());
SlotIndex SegStart = enterIntvBefore(std::min(BI.FirstUse,
BI.LastSplitPoint));
if (!BI.LiveOut || BI.LastUse < BI.LastSplitPoint) {
LastSplitPoint));
if (!BI.LiveOut || BI.LastUse < LastSplitPoint) {
useIntv(SegStart, leaveIntvAfter(BI.LastUse));
} else {
// The last use is after the last valid split point.
SlotIndex SegStop = leaveIntvBefore(BI.LastSplitPoint);
SlotIndex SegStop = leaveIntvBefore(LastSplitPoint);
useIntv(SegStart, SegStop);
overlapIntv(SegStop, BI.LastUse);
}

2
llvm/lib/CodeGen/SplitKit.h
View File

@ -77,8 +77,6 @@ public:
SlotIndex LastUse; ///< Last instr using current reg.
SlotIndex Kill; ///< Interval end point inside block.
SlotIndex Def; ///< Interval start point inside block.
/// Last possible point for splitting live ranges.
SlotIndex LastSplitPoint;
bool Uses; ///< Current reg has uses or defs in block.
bool LiveThrough; ///< Live in whole block (Templ 5. or 6. above).
bool LiveIn; ///< Current reg is live in.