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Extract SpillPlacement::addLinks for handling the special transparent blocks.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129079 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-04-07 17:27:46 +00:00
parent 949666ea16
commit 7b41fbe872
3 changed files with 49 additions and 37 deletions
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44
lib/CodeGen/RegAllocGreedy.cpp
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@ -123,9 +123,13 @@ class RAGreedy : public MachineFunctionPass,
/// Cached per-block interference maps
InterferenceCache IntfCache;
/// All basic blocks where the current register is live.
/// All basic blocks where the current register has uses.
SmallVector<SpillPlacement::BlockConstraint, 8> SplitConstraints;
/// All basic blocks where the current register is live-through and
/// interference free.
SmallVector<unsigned, 8> TransparentBlocks;
/// Global live range splitting candidate info.
struct GlobalSplitCandidate {
unsigned PhysReg;
@ -475,6 +479,7 @@ bool RAGreedy::addSplitConstraints(unsigned PhysReg, float &Cost) {
const unsigned GroupSize = 8;
SpillPlacement::BlockConstraint BCS[GroupSize];
unsigned B = 0;
TransparentBlocks.clear();
ArrayRef<unsigned> ThroughBlocks = SA->getThroughBlocks();
for (unsigned i = 0; i != ThroughBlocks.size(); ++i) {
@ -483,23 +488,23 @@ bool RAGreedy::addSplitConstraints(unsigned PhysReg, float &Cost) {
BCS[B].Number = Number;
Intf.moveToBlock(Number);
if (Intf.hasInterference()) {
// Interference for the live-in value.
if (Intf.first() <= Indexes->getMBBStartIdx(Number))
BCS[B].Entry = SpillPlacement::MustSpill;
else
BCS[B].Entry = SpillPlacement::PrefSpill;
// Interference for the live-out value.
if (Intf.last() >= SA->getLastSplitPoint(Number))
BCS[B].Exit = SpillPlacement::MustSpill;
else
BCS[B].Exit = SpillPlacement::PrefSpill;
} else {
// No interference, transparent block.
BCS[B].Entry = BCS[B].Exit = SpillPlacement::DontCare;
if (!Intf.hasInterference()) {
TransparentBlocks.push_back(Number);
continue;
}
// Interference for the live-in value.
if (Intf.first() <= Indexes->getMBBStartIdx(Number))
BCS[B].Entry = SpillPlacement::MustSpill;
else
BCS[B].Entry = SpillPlacement::PrefSpill;
// Interference for the live-out value.
if (Intf.last() >= SA->getLastSplitPoint(Number))
BCS[B].Exit = SpillPlacement::MustSpill;
else
BCS[B].Exit = SpillPlacement::PrefSpill;
if (++B == GroupSize) {
ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
SpillPlacer->addConstraints(Array);
@ -512,7 +517,12 @@ bool RAGreedy::addSplitConstraints(unsigned PhysReg, float &Cost) {
ArrayRef<SpillPlacement::BlockConstraint> Array(BCS, B);
SpillPlacer->addConstraints(Array);
return SpillPlacer->getPositiveNodes() != 0;
if (SpillPlacer->getPositiveNodes() == 0)
return false;
// There is still some positive bias. Add all the links.
SpillPlacer->addLinks(TransparentBlocks);
return true;
}

35
lib/CodeGen/SpillPlacement.cpp
View File

@ -213,23 +213,6 @@ void SpillPlacement::addConstraints(ArrayRef<BlockConstraint> LiveBlocks) {
for (ArrayRef<BlockConstraint>::iterator I = LiveBlocks.begin(),
E = LiveBlocks.end(); I != E; ++I) {
float Freq = getBlockFrequency(I->Number);
// Is this a transparent block? Link ingoing and outgoing bundles.
if (I->Entry == DontCare && I->Exit == DontCare) {
unsigned ib = bundles->getBundle(I->Number, 0);
unsigned ob = bundles->getBundle(I->Number, 1);
// Ignore self-loops.
if (ib == ob)
continue;
activate(ib);
activate(ob);
nodes[ib].addLink(ob, Freq, 1);
nodes[ob].addLink(ib, Freq, 0);
continue;
}
// This block is not transparent, but it can still add bias.
const float Bias[] = {
0, // DontCare,
1, // PrefReg,
@ -253,6 +236,24 @@ void SpillPlacement::addConstraints(ArrayRef<BlockConstraint> LiveBlocks) {
}
}
void SpillPlacement::addLinks(ArrayRef<unsigned> Links) {
for (ArrayRef<unsigned>::iterator I = Links.begin(), E = Links.end(); I != E;
++I) {
unsigned Number = *I;
unsigned ib = bundles->getBundle(Number, 0);
unsigned ob = bundles->getBundle(Number, 1);
// Ignore self-loops.
if (ib == ob)
continue;
activate(ib);
activate(ob);
float Freq = getBlockFrequency(Number);
nodes[ib].addLink(ob, Freq, 1);
nodes[ob].addLink(ib, Freq, 0);
}
}
/// iterate - Repeatedly update the Hopfield nodes until stability or the
/// maximum number of iterations is reached.
/// @param Linked - Numbers of linked nodes that need updating.

7
lib/CodeGen/SpillPlacement.h
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@ -89,11 +89,12 @@ public:
/// addConstraints - Add constraints and biases. This method may be called
/// more than once to accumulate constraints.
/// @param LiveBlocks Constraints for blocks that have the variable live in or
/// live out. DontCare/DontCare means the variable is live
/// through the block. DontCare/X means the variable is live
/// out, but not live in.
/// live out.
void addConstraints(ArrayRef<BlockConstraint> LiveBlocks);
/// addLinks - Add transparent blocks with the given numbers.
void addLinks(ArrayRef<unsigned> Links);
/// getPositiveNodes - Return the total number of graph nodes with a positive
/// bias after adding constraints.
unsigned getPositiveNodes() const { return PositiveNodes; }