[llvm-commits] [llvm] r61514 - /llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp
Owen Anderson
resistor at mac.com
Tue Dec 30 18:00:31 PST 2008
Author: resistor
Date: Tue Dec 30 20:00:25 2008
New Revision: 61514
URL: http://llvm.org/viewvc/llvm-project?rev=61514&view=rev
Log:
Get live interval reconstruction several steps closer to working.
Modified:
llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp
Modified: llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp?rev=61514&r1=61513&r2=61514&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp (original)
+++ llvm/trunk/lib/CodeGen/PreAllocSplitting.cpp Tue Dec 30 20:00:25 2008
@@ -173,12 +173,14 @@
void RenumberValno(VNInfo* VN);
void ReconstructLiveInterval(LiveInterval* LI);
VNInfo* PerformPHIConstruction(MachineBasicBlock::iterator use,
+ MachineBasicBlock* MBB,
LiveInterval* LI,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
DenseMap<MachineInstr*, VNInfo*>& NewVNs,
- DenseMap<MachineBasicBlock*, VNInfo*>& Visited,
- bool toplevel = false);
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool toplevel, bool intrablock);
};
} // end anonymous namespace
@@ -589,21 +591,30 @@
/// construction algorithm to compute the ranges and valnos for an interval.
VNInfo* PreAllocSplitting::PerformPHIConstruction(
MachineBasicBlock::iterator use,
+ MachineBasicBlock* MBB,
LiveInterval* LI,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Defs,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> >& Uses,
DenseMap<MachineInstr*, VNInfo*>& NewVNs,
- DenseMap<MachineBasicBlock*, VNInfo*>& Visited,
- bool toplevel) {
+ DenseMap<MachineBasicBlock*, VNInfo*>& LiveOut,
+ DenseMap<MachineBasicBlock*, VNInfo*>& Phis,
+ bool toplevel, bool intrablock) {
// Return memoized result if it's available.
- if (Visited.count(use->getParent()))
- return Visited[use->getParent()];
+ if (intrablock && NewVNs.count(use))
+ return NewVNs[use];
+ else if (!intrablock && LiveOut.count(MBB))
+ return LiveOut[MBB];
+
+ // Insert a sentinel into the map (which also acts as the DFS stack) so that
+ // we won't get stuck in infinite recursion when processing a loop.
+ if (!intrablock)
+ LiveOut[MBB] = 0;
typedef DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 2> > RegMap;
// Check if our block contains any uses or defs.
- bool ContainsDefs = Defs.count(use->getParent());
- bool ContainsUses = Uses.count(use->getParent());
+ bool ContainsDefs = Defs.count(MBB);
+ bool ContainsUses = Uses.count(MBB);
VNInfo* ret = 0;
@@ -611,32 +622,42 @@
if (!ContainsDefs && !ContainsUses) {
Fallback:
// NOTE: Because this is the fallback case from other cases, we do NOT
- // assume that we are not at toplevel here.
+ // assume that we are not intrablock here.
+ if (Phis.count(MBB)) return Phis[MBB];
- // If there are no uses or defs between our starting point and the beginning
- // of the block, then recursive perform phi construction on our predecessors
- MachineBasicBlock* MBB = use->getParent();
- DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs;
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), LI, Defs, Uses,
- NewVNs, Visited, false);
- IncomingVNs[*PI] = Incoming;
- }
+ unsigned StartIndex = LIs->getMBBStartIdx(MBB);
- // If only one VNInfo came back from our predecessors, just use that one...
- if (IncomingVNs.size() == 1) {
- ret = IncomingVNs.begin()->second;
- unsigned StartIndex = LIs->getMBBStartIdx(use->getParent());
+ if (MBB->pred_size() == 1) {
+ Phis[MBB] = ret = PerformPHIConstruction((*MBB->pred_begin())->end(),
+ *(MBB->pred_begin()), LI, Defs,
+ Uses, NewVNs, LiveOut, Phis,
+ false, false);
unsigned EndIndex = 0;
- if (toplevel) {
+ if (intrablock) {
EndIndex = LIs->getInstructionIndex(use);
EndIndex = LiveIntervals::getUseIndex(EndIndex);
} else
- EndIndex = LIs->getMBBEndIdx(use->getParent());
+ EndIndex = LIs->getMBBEndIdx(MBB);
- LI->addRange(LiveRange(StartIndex, EndIndex, ret));
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
} else {
+ Phis[MBB] = ret = LI->getNextValue(~0U, /*FIXME*/ 0,
+ LIs->getVNInfoAllocator());
+ if (!intrablock) LiveOut[MBB] = ret;
+
+ // If there are no uses or defs between our starting point and the
+ // beginning of the block, then recursive perform phi construction
+ // on our predecessors.
+ DenseMap<MachineBasicBlock*, VNInfo*> IncomingVNs;
+ for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
+ PE = MBB->pred_end(); PI != PE; ++PI) {
+ VNInfo* Incoming = PerformPHIConstruction((*PI)->end(), *PI, LI, Defs,
+ Uses, NewVNs, LiveOut, Phis,
+ false, false);
+ if (Incoming != 0)
+ IncomingVNs[*PI] = Incoming;
+ }
+
// Otherwise, merge the incoming VNInfos with a phi join. Create a new
// VNInfo to represent the joined value.
for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator I =
@@ -646,29 +667,26 @@
LI->addKill(I->second, KillIndex);
}
- unsigned StartIndex = LIs->getMBBStartIdx(use->getParent());
unsigned EndIndex = 0;
- if (toplevel) {
+ if (intrablock) {
EndIndex = LIs->getInstructionIndex(use);
EndIndex = LiveIntervals::getUseIndex(EndIndex);
} else
- EndIndex = LIs->getMBBEndIdx(use->getParent());
- ret = LI->getNextValue(StartIndex, /*FIXME*/ 0,
- LIs->getVNInfoAllocator());
- LI->addRange(LiveRange(StartIndex, EndIndex, ret));
+ EndIndex = LIs->getMBBEndIdx(MBB);
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
}
} else if (ContainsDefs && !ContainsUses) {
- SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[use->getParent()];
+ SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
// Search for the def in this block. If we don't find it before the
// instruction we care about, go to the fallback case. Note that that
- // should never happen: this cannot be a toplevel block, so use should
+ // should never happen: this cannot be intrablock, so use should
// always be an end() iterator.
- assert(use == use->getParent()->end() && "No use marked in toplevel block");
+ assert(use == MBB->end() && "No use marked in intrablock");
MachineBasicBlock::iterator walker = use;
--walker;
- while (walker != use->getParent()->begin())
+ while (walker != MBB->begin())
if (BlockDefs.count(walker)) {
break;
} else
@@ -677,23 +695,23 @@
// Once we've found it, extend its VNInfo to our instruction.
unsigned DefIndex = LIs->getInstructionIndex(walker);
DefIndex = LiveIntervals::getDefIndex(DefIndex);
- unsigned EndIndex = LIs->getMBBEndIdx(use->getParent());
+ unsigned EndIndex = LIs->getMBBEndIdx(MBB);
ret = NewVNs[walker];
- LI->addRange(LiveRange(DefIndex, EndIndex, ret));
+ LI->addRange(LiveRange(DefIndex, EndIndex+1, ret));
} else if (!ContainsDefs && ContainsUses) {
- SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[use->getParent()];
+ SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
// Search for the use in this block that precedes the instruction we care
// about, going to the fallback case if we don't find it.
- if (use == use->getParent()->begin())
+ if (use == MBB->begin())
goto Fallback;
MachineBasicBlock::iterator walker = use;
--walker;
bool found = false;
- while (walker != use->getParent()->begin())
+ while (walker != MBB->begin())
if (BlockUses.count(walker)) {
found = true;
break;
@@ -711,39 +729,39 @@
unsigned UseIndex = LIs->getInstructionIndex(walker);
UseIndex = LiveIntervals::getUseIndex(UseIndex);
unsigned EndIndex = 0;
- if (toplevel) {
- EndIndex = LIs->getInstructionIndex(walker);
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
EndIndex = LiveIntervals::getUseIndex(EndIndex);
} else
- EndIndex = LIs->getMBBEndIdx(use->getParent());
+ EndIndex = LIs->getMBBEndIdx(MBB);
// Now, recursively phi construct the VNInfo for the use we found,
// and then extend it to include the instruction we care about
- ret = PerformPHIConstruction(walker, LI, Defs, Uses,
- NewVNs, Visited, false);
+ ret = PerformPHIConstruction(walker, MBB, LI, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
// FIXME: Need to set kills properly for inter-block stuff.
if (LI->isKill(ret, UseIndex)) LI->removeKill(ret, UseIndex);
- if (toplevel)
+ if (intrablock)
LI->addKill(ret, EndIndex);
- LI->addRange(LiveRange(UseIndex, EndIndex, ret));
+ LI->addRange(LiveRange(UseIndex, EndIndex+1, ret));
} else if (ContainsDefs && ContainsUses){
- SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[use->getParent()];
- SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[use->getParent()];
+ SmallPtrSet<MachineInstr*, 2>& BlockDefs = Defs[MBB];
+ SmallPtrSet<MachineInstr*, 2>& BlockUses = Uses[MBB];
// This case is basically a merging of the two preceding case, with the
// special note that checking for defs must take precedence over checking
// for uses, because of two-address instructions.
- if (use == use->getParent()->begin())
+ if (use == MBB->begin())
goto Fallback;
MachineBasicBlock::iterator walker = use;
--walker;
bool foundDef = false;
bool foundUse = false;
- while (walker != use->getParent()->begin())
+ while (walker != MBB->begin())
if (BlockDefs.count(walker)) {
foundDef = true;
break;
@@ -767,29 +785,30 @@
StartIndex = foundDef ? LiveIntervals::getDefIndex(StartIndex) :
LiveIntervals::getUseIndex(StartIndex);
unsigned EndIndex = 0;
- if (toplevel) {
- EndIndex = LIs->getInstructionIndex(walker);
+ if (intrablock) {
+ EndIndex = LIs->getInstructionIndex(use);
EndIndex = LiveIntervals::getUseIndex(EndIndex);
} else
- EndIndex = LIs->getMBBEndIdx(use->getParent());
+ EndIndex = LIs->getMBBEndIdx(MBB);
if (foundDef)
ret = NewVNs[walker];
else
- ret = PerformPHIConstruction(walker, LI, Defs, Uses,
- NewVNs, Visited, false);
+ ret = PerformPHIConstruction(walker, MBB, LI, Defs, Uses,
+ NewVNs, LiveOut, Phis, false, true);
if (foundUse && LI->isKill(ret, StartIndex))
LI->removeKill(ret, StartIndex);
- if (toplevel) {
+ if (intrablock) {
LI->addKill(ret, EndIndex);
}
- LI->addRange(LiveRange(StartIndex, EndIndex, ret));
+ LI->addRange(LiveRange(StartIndex, EndIndex+1, ret));
}
// Memoize results so we don't have to recompute them.
- if (!toplevel) Visited[use->getParent()] = ret;
+ if (!intrablock) LiveOut[MBB] = ret;
+ else NewVNs[use] = ret;
return ret;
}
@@ -829,10 +848,12 @@
// Now, actually process every use and use a phi construction algorithm
// to walk from it to its reaching definitions, building VNInfos along
// the way.
+ DenseMap<MachineBasicBlock*, VNInfo*> LiveOut;
+ DenseMap<MachineBasicBlock*, VNInfo*> Phis;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(LI->reg),
UE = MRI->use_end(); UI != UE; ++UI) {
- DenseMap<MachineBasicBlock*, VNInfo*> Visited;
- PerformPHIConstruction(&*UI, LI, Defs, Uses, NewVNs, Visited, true);
+ PerformPHIConstruction(&*UI, UI->getParent(), LI, Defs,
+ Uses, NewVNs, LiveOut, Phis, true, true);
}
// Add ranges for dead defs
@@ -840,12 +861,11 @@
DE = MRI->def_end(); DI != DE; ++DI) {
unsigned DefIdx = LIs->getInstructionIndex(&*DI);
DefIdx = LiveIntervals::getDefIndex(DefIdx);
- unsigned UseIdx = LiveIntervals::getUseIndex(DefIdx);
if (LI->liveAt(DefIdx)) continue;
VNInfo* DeadVN = NewVNs[&*DI];
- LI->addRange(LiveRange(DefIdx, UseIdx, DeadVN));
+ LI->addRange(LiveRange(DefIdx, DefIdx+1, DeadVN));
LI->addKill(DeadVN, DefIdx);
}
}
@@ -1283,7 +1303,7 @@
UpdateRegisterInterval(ValNo, LIs->getUseIndex(SpillIndex)+1,
LIs->getDefIndex(RestoreIndex));
-
+
++NumSplits;
return true;
}
@@ -1293,7 +1313,7 @@
LIs->getDefIndex(RestoreIndex));
RepairLiveInterval(CurrLI, ValNo, DefMI, RestoreIndex);
-
+
++NumSplits;
return true;
}
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