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Use the EdgeBundles analysis in X86FloatingPoint instead of recomputing CFG

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bundles in the pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122833 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-01-04 21:10:11 +00:00
parent 8dd070edc2
commit 631ee4b89f
2 changed files with 17 additions and 87 deletions
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3
include/llvm/CodeGen/EdgeBundles.h
View File

@ -37,6 +37,9 @@ public:
/// bundle number for basic block #N
unsigned getBundle(unsigned N, bool Out) const { return EC[2 * N + Out]; }
/// getNumBundles - Return the total number of bundles in the CFG.
unsigned getNumBundles() const { return EC.getNumClasses(); }
/// getMachineFunction - Return the last machine function computed.
const MachineFunction *getMachineFunction() const { return MF; }

101
lib/Target/X86/X86FloatingPoint.cpp
View File

@ -97,7 +97,7 @@ namespace {
// FixStack[i] == getStackEntry(i) for all i < FixCount.
unsigned char FixStack[8];
LiveBundle(unsigned m = 0) : Mask(m), FixCount(0) {}
LiveBundle() : Mask(0), FixCount(0) {}
// Have the live registers been assigned a stack order yet?
bool isFixed() const { return !Mask || FixCount; }
@ -107,10 +107,8 @@ namespace {
// with no live FP registers.
SmallVector<LiveBundle, 8> LiveBundles;
// Map each MBB in the current function to an (ingoing, outgoing) index into
// LiveBundles. Blocks with no FP registers live in or out map to (0, 0)
// and are not actually stored in the map.
DenseMap<MachineBasicBlock*, std::pair<unsigned, unsigned> > BlockBundle;
// The edge bundle analysis provides indices into the LiveBundles vector.
EdgeBundles *Bundles;
// Return a bitmask of FP registers in block's live-in list.
unsigned calcLiveInMask(MachineBasicBlock *MBB) {
@ -287,6 +285,7 @@ bool FPS::runOnMachineFunction(MachineFunction &MF) {
// Early exit.
if (!FPIsUsed) return false;
Bundles = &getAnalysis<EdgeBundles>();
TII = MF.getTarget().getInstrInfo();
// Prepare cross-MBB liveness.
@ -311,7 +310,6 @@ bool FPS::runOnMachineFunction(MachineFunction &MF) {
if (Processed.insert(BB))
Changed |= processBasicBlock(MF, *BB);
BlockBundle.clear();
LiveBundles.clear();
return Changed;
@ -324,90 +322,16 @@ bool FPS::runOnMachineFunction(MachineFunction &MF) {
/// registers may be implicitly defined, or not used by all successors.
void FPS::bundleCFG(MachineFunction &MF) {
assert(LiveBundles.empty() && "Stale data in LiveBundles");
assert(BlockBundle.empty() && "Stale data in BlockBundle");
SmallPtrSet<MachineBasicBlock*, 8> PropDown, PropUp;
LiveBundles.resize(Bundles->getNumBundles());
// LiveBundle[0] is the empty live-in set.
LiveBundles.resize(1);
// First gather the actual live-in masks for all MBBs.
// Gather the actual live-in masks for all MBBs.
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
MachineBasicBlock *MBB = I;
const unsigned Mask = calcLiveInMask(MBB);
if (!Mask)
continue;
// Ingoing bundle index.
unsigned &Idx = BlockBundle[MBB].first;
// Already assigned an ingoing bundle?
if (Idx)
continue;
// Allocate a new LiveBundle struct for this block's live-ins.
const unsigned BundleIdx = Idx = LiveBundles.size();
DEBUG(dbgs() << "Creating LB#" << BundleIdx << ": in:BB#"
<< MBB->getNumber());
LiveBundles.push_back(Mask);
LiveBundle &Bundle = LiveBundles.back();
// Make sure all predecessors have the same live-out set.
PropUp.insert(MBB);
// Keep pushing liveness up and down the CFG until convergence.
// Only critical edges cause iteration here, but when they do, multiple
// blocks can be assigned to the same LiveBundle index.
do {
// Assign BundleIdx as liveout from predecessors in PropUp.
for (SmallPtrSet<MachineBasicBlock*, 16>::iterator I = PropUp.begin(),
E = PropUp.end(); I != E; ++I) {
MachineBasicBlock *MBB = *I;
for (MachineBasicBlock::const_pred_iterator LinkI = MBB->pred_begin(),
LinkE = MBB->pred_end(); LinkI != LinkE; ++LinkI) {
MachineBasicBlock *PredMBB = *LinkI;
// PredMBB's liveout bundle should be set to LIIdx.
unsigned &Idx = BlockBundle[PredMBB].second;
if (Idx) {
assert(Idx == BundleIdx && "Inconsistent CFG");
continue;
}
Idx = BundleIdx;
DEBUG(dbgs() << " out:BB#" << PredMBB->getNumber());
// Propagate to siblings.
if (PredMBB->succ_size() > 1)
PropDown.insert(PredMBB);
}
}
PropUp.clear();
// Assign BundleIdx as livein to successors in PropDown.
for (SmallPtrSet<MachineBasicBlock*, 16>::iterator I = PropDown.begin(),
E = PropDown.end(); I != E; ++I) {
MachineBasicBlock *MBB = *I;
for (MachineBasicBlock::const_succ_iterator LinkI = MBB->succ_begin(),
LinkE = MBB->succ_end(); LinkI != LinkE; ++LinkI) {
MachineBasicBlock *SuccMBB = *LinkI;
// LinkMBB's livein bundle should be set to BundleIdx.
unsigned &Idx = BlockBundle[SuccMBB].first;
if (Idx) {
assert(Idx == BundleIdx && "Inconsistent CFG");
continue;
}
Idx = BundleIdx;
DEBUG(dbgs() << " in:BB#" << SuccMBB->getNumber());
// Propagate to siblings.
if (SuccMBB->pred_size() > 1)
PropUp.insert(SuccMBB);
// Also accumulate the bundle liveness mask from the liveins here.
Bundle.Mask |= calcLiveInMask(SuccMBB);
}
}
PropDown.clear();
} while (!PropUp.empty());
DEBUG({
dbgs() << " live:";
for (unsigned i = 0; i < 8; ++i)
if (Bundle.Mask & (1<<i))
dbgs() << " %FP" << i;
dbgs() << '\n';
});
// Update MBB ingoing bundle mask.
LiveBundles[Bundles->getBundle(MBB->getNumber(), false)].Mask |= Mask;
}
}
@ -495,13 +419,15 @@ bool FPS::processBasicBlock(MachineFunction &MF, MachineBasicBlock &BB) {
return Changed;
}
/// setupBlockStack - Use the BlockBundle map to set up our model of the stack
/// setupBlockStack - Use the live bundles to set up our model of the stack
/// to match predecessors' live out stack.
void FPS::setupBlockStack() {
DEBUG(dbgs() << "\nSetting up live-ins for BB#" << MBB->getNumber()
<< " derived from " << MBB->getName() << ".\n");
StackTop = 0;
const LiveBundle &Bundle = LiveBundles[BlockBundle.lookup(MBB).first];
// Get the live-in bundle for MBB.
const LiveBundle &Bundle =
LiveBundles[Bundles->getBundle(MBB->getNumber(), false)];
if (!Bundle.Mask) {
DEBUG(dbgs() << "Block has no FP live-ins.\n");
@ -538,7 +464,8 @@ void FPS::finishBlockStack() {
DEBUG(dbgs() << "Setting up live-outs for BB#" << MBB->getNumber()
<< " derived from " << MBB->getName() << ".\n");
unsigned BundleIdx = BlockBundle.lookup(MBB).second;
// Get MBB's live-out bundle.
unsigned BundleIdx = Bundles->getBundle(MBB->getNumber(), true);
LiveBundle &Bundle = LiveBundles[BundleIdx];
// We may need to kill and define some registers to match successors.