[llvm-commits] [llvm] r52013 - /llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
Owen Anderson
resistor at mac.com
Thu Jun 5 10:22:53 PDT 2008
Author: resistor
Date: Thu Jun 5 12:22:53 2008
New Revision: 52013
URL: http://llvm.org/viewvc/llvm-project?rev=52013&view=rev
Log:
Use the newly created helper on LiveIntervals.
Modified:
llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
Modified: llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp?rev=52013&r1=52012&r2=52013&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp (original)
+++ llvm/trunk/lib/CodeGen/StrongPHIElimination.cpp Thu Jun 5 12:22:53 2008
@@ -52,8 +52,9 @@
// used as operands to another another PHI node
std::set<unsigned> UsedByAnother;
- // RenameSets are the sets of operands (and their VNInfo IDs) to a PHI
- // (the defining instruction of the key) that can be renamed without copies.
+ // RenameSets are the is a map from a PHI-defined register
+ // to the input registers to be coalesced along with the index
+ // of the input registers.
std::map<unsigned, std::map<unsigned, unsigned> > RenameSets;
// PhiValueNumber holds the ID numbers of the VNs for each phi that we're
@@ -466,15 +467,11 @@
UsedByAnother.insert(SrcReg);
} else {
// Otherwise, add it to the renaming set
- LiveInterval& I = LI.getOrCreateInterval(SrcReg);
// We need to subtract one from the index because live ranges are open
// at the end.
unsigned idx = LI.getMBBEndIdx(P->getOperand(i).getMBB()) - 1;
- VNInfo* VN = I.getLiveRangeContaining(idx)->valno;
- assert(VN && "No VNInfo for register?");
-
- PHIUnion.insert(std::make_pair(SrcReg, VN->id));
+ PHIUnion.insert(std::make_pair(SrcReg, idx));
UnionedBlocks.insert(MRI.getVRegDef(SrcReg)->getParent());
}
}
@@ -744,22 +741,9 @@
// PHI, we don't create multiple overlapping live intervals.
std::set<unsigned> RegHandled;
for (SmallVector<std::pair<unsigned, MachineInstr*>, 4>::iterator I =
- InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I) {
- if (!RegHandled.count(I->first)) {
- LiveInterval& Interval = LI.getOrCreateInterval(I->first);
- VNInfo* VN = Interval.getNextValue(
- LI.getInstructionIndex(I->second) + LiveIntervals::InstrSlots::DEF,
- I->second, LI.getVNInfoAllocator());
- VN->hasPHIKill = true;
- VN->kills.push_back(LI.getMBBEndIdx(I->second->getParent()));
- LiveRange LR(LI.getInstructionIndex(I->second) +
- LiveIntervals::InstrSlots::DEF,
- LI.getMBBEndIdx(I->second->getParent()) + 1, VN);
- Interval.addRange(LR);
-
- RegHandled.insert(I->first);
- }
- }
+ InsertedPHIDests.begin(), E = InsertedPHIDests.end(); I != E; ++I)
+ if (!RegHandled.count(I->first))
+ LI.addLiveRangeToEndOfBlock(I->first, I->second);
}
/// InsertCopies - insert copies into MBB and all of its successors
@@ -794,111 +778,30 @@
Stacks[*I].pop_back();
}
-/// ComputeUltimateVN - Assuming we are going to join two live intervals,
-/// compute what the resultant value numbers for each value in the input two
-/// ranges will be. This is complicated by copies between the two which can
-/// and will commonly cause multiple value numbers to be merged into one.
-///
-/// VN is the value number that we're trying to resolve. InstDefiningValue
-/// keeps track of the new InstDefiningValue assignment for the result
-/// LiveInterval. ThisFromOther/OtherFromThis are sets that keep track of
-/// whether a value in this or other is a copy from the opposite set.
-/// ThisValNoAssignments/OtherValNoAssignments keep track of value #'s that have
-/// already been assigned.
-///
-/// ThisFromOther[x] - If x is defined as a copy from the other interval, this
-/// contains the value number the copy is from.
-///
-static unsigned ComputeUltimateVN(VNInfo *VNI,
- SmallVector<VNInfo*, 16> &NewVNInfo,
- DenseMap<VNInfo*, VNInfo*> &ThisFromOther,
- DenseMap<VNInfo*, VNInfo*> &OtherFromThis,
- SmallVector<int, 16> &ThisValNoAssignments,
- SmallVector<int, 16> &OtherValNoAssignments) {
- unsigned VN = VNI->id;
-
- // If the VN has already been computed, just return it.
- if (ThisValNoAssignments[VN] >= 0)
- return ThisValNoAssignments[VN];
-// assert(ThisValNoAssignments[VN] != -2 && "Cyclic case?");
-
- // If this val is not a copy from the other val, then it must be a new value
- // number in the destination.
- DenseMap<VNInfo*, VNInfo*>::iterator I = ThisFromOther.find(VNI);
- if (I == ThisFromOther.end()) {
- NewVNInfo.push_back(VNI);
- return ThisValNoAssignments[VN] = NewVNInfo.size()-1;
- }
- VNInfo *OtherValNo = I->second;
-
- // Otherwise, this *is* a copy from the RHS. If the other side has already
- // been computed, return it.
- if (OtherValNoAssignments[OtherValNo->id] >= 0)
- return ThisValNoAssignments[VN] = OtherValNoAssignments[OtherValNo->id];
-
- // Mark this value number as currently being computed, then ask what the
- // ultimate value # of the other value is.
- ThisValNoAssignments[VN] = -2;
- unsigned UltimateVN =
- ComputeUltimateVN(OtherValNo, NewVNInfo, OtherFromThis, ThisFromOther,
- OtherValNoAssignments, ThisValNoAssignments);
- return ThisValNoAssignments[VN] = UltimateVN;
-}
-
void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
unsigned secondary,
- unsigned secondaryVN) {
+ unsigned secondaryIdx) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
LiveInterval& LHS = LI.getOrCreateInterval(primary);
LiveInterval& RHS = LI.getOrCreateInterval(secondary);
- // Compute the final value assignment, assuming that the live ranges can be
- // coalesced.
- SmallVector<int, 16> LHSValNoAssignments;
- SmallVector<int, 16> RHSValNoAssignments;
- SmallVector<VNInfo*, 16> NewVNInfo;
-
- LHSValNoAssignments.resize(LHS.getNumValNums(), -1);
- RHSValNoAssignments.resize(RHS.getNumValNums(), -1);
- NewVNInfo.reserve(LHS.getNumValNums() + RHS.getNumValNums());
-
- for (LiveInterval::vni_iterator I = LHS.vni_begin(), E = LHS.vni_end();
- I != E; ++I) {
- VNInfo *VNI = *I;
- unsigned VN = VNI->id;
- if (LHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
- continue;
-
- NewVNInfo.push_back(VNI);
- LHSValNoAssignments[VN] = NewVNInfo.size()-1;
- }
-
- for (LiveInterval::vni_iterator I = RHS.vni_begin(), E = RHS.vni_end();
- I != E; ++I) {
- VNInfo *VNI = *I;
- unsigned VN = VNI->id;
- if (RHSValNoAssignments[VN] >= 0 || VNI->def == ~1U)
- continue;
-
- NewVNInfo.push_back(VNI);
- RHSValNoAssignments[VN] = NewVNInfo.size()-1;
- }
-
- // If we get here, we know that we can coalesce the live ranges. Ask the
- // intervals to coalesce themselves now.
-
- LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo);
- LI.removeInterval(secondary);
+ LI.computeNumbering();
- // The valno that was previously the input to the PHI node
- // now has a PHIKill.
- LHS.getValNumInfo(RHSValNoAssignments[secondaryVN])->hasPHIKill = true;
+ const LiveRange* RangeMergingIn = RHS.getLiveRangeContaining(secondaryIdx);
+ VNInfo* NewVN = LHS.getNextValue(secondaryIdx, RangeMergingIn->valno->copy,
+ LI.getVNInfoAllocator());
+ NewVN->hasPHIKill = true;
+ LiveRange NewRange(RangeMergingIn->start, RangeMergingIn->end, NewVN);
+ LHS.addRange(NewRange);
+ RHS.removeRange(RangeMergingIn->start, RangeMergingIn->end, true);
}
bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
LiveIntervals& LI = getAnalysis<LiveIntervals>();
+ LI.dump();
+
// Compute DFS numbers of each block
computeDFS(Fn);
@@ -909,7 +812,7 @@
processBlock(I);
// Insert copies
- // FIXME: This process should probably preserve LiveVariables
+ // FIXME: This process should probably preserve LiveIntervals
SmallPtrSet<MachineBasicBlock*, 16> visited;
InsertCopies(Fn.begin(), visited);
@@ -961,5 +864,7 @@
LI.computeNumbering();
+ LI.dump();
+
return true;
}
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