diff options
-rw-r--r-- | lib/CodeGen/LiveIntervalAnalysis.cpp | 3 | ||||
-rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 68 |
2 files changed, 62 insertions, 9 deletions
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index 6c26b79..dca3058 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -742,9 +742,6 @@ void LiveIntervals::extendToIndices(LiveInterval *LI, void LiveIntervals::pruneValue(LiveInterval *LI, SlotIndex Kill, SmallVectorImpl<SlotIndex> *EndPoints) { LiveRangeQuery LRQ(*LI, Kill); - assert (!LRQ.valueDefined() && "Can't prune value at the defining instr"); - - // Also can't prune a value that isn't there. VNInfo *VNI = LRQ.valueOut(); if (!VNI) return; diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index b372b86..e9bfac9 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -1246,8 +1246,15 @@ class JoinVals { // Value in the other live range that overlaps this def, if any. VNInfo *OtherVNI; + // True when the live range of this value will be pruned because of an + // overlapping CR_Replace value in the other live range. + bool Pruned; + + // True once Pruned above has been computed. + bool PrunedComputed; + Val() : Resolution(CR_Keep), WriteLanes(0), ValidLanes(0), - RedefVNI(0), OtherVNI(0) {} + RedefVNI(0), OtherVNI(0), Pruned(false), PrunedComputed(false) {} bool isAnalyzed() const { return WriteLanes != 0; } }; @@ -1262,6 +1269,7 @@ class JoinVals { bool taintExtent(unsigned, unsigned, JoinVals&, SmallVectorImpl<std::pair<SlotIndex, unsigned> >&); bool usesLanes(MachineInstr *MI, unsigned, unsigned, unsigned); + bool isPrunedValue(unsigned ValNo, JoinVals &Other); public: JoinVals(LiveInterval &li, unsigned subIdx, @@ -1527,6 +1535,12 @@ void JoinVals::computeAssignment(unsigned ValNo, JoinVals &Other) { << V.OtherVNI->def << " --> @" << NewVNInfo[Assignments[ValNo]]->def << '\n'); break; + case CR_Replace: + case CR_Unresolved: + // The other value is going to be pruned if this join is successful. + assert(V.OtherVNI && "OtherVNI not assigned, can't prune"); + Other.Vals[V.OtherVNI->id].Pruned = true; + // Fall through. default: // This value number needs to go in the final joined live range. Assignments[ValNo] = NewVNInfo.size(); @@ -1682,15 +1696,57 @@ bool JoinVals::resolveConflicts(JoinVals &Other) { return true; } +// Determine if ValNo is a copy of a value number in LI or Other.LI that will +// be pruned: +// +// %dst = COPY %src +// %src = COPY %dst <-- This value to be pruned. +// %dst = COPY %src <-- This value is a copy of a pruned value. +// +bool JoinVals::isPrunedValue(unsigned ValNo, JoinVals &Other) { + Val &V = Vals[ValNo]; + if (V.Pruned || V.PrunedComputed) + return V.Pruned; + + if (V.Resolution != CR_Erase && V.Resolution != CR_Merge) + return V.Pruned; + + // Follow copies up the dominator tree and check if any intermediate value + // has been pruned. + V.PrunedComputed = true; + V.Pruned = Other.isPrunedValue(V.OtherVNI->id, *this); + return V.Pruned; +} + void JoinVals::pruneValues(JoinVals &Other, SmallVectorImpl<SlotIndex> &EndPoints) { for (unsigned i = 0, e = LI.getNumValNums(); i != e; ++i) { - if (Vals[i].Resolution != CR_Replace) - continue; SlotIndex Def = LI.getValNumInfo(i)->def; - LIS->pruneValue(&Other.LI, Def, &EndPoints); - DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def - << ": " << Other.LI << '\n'); + switch (Vals[i].Resolution) { + case CR_Keep: + break; + case CR_Replace: + // This value takes precedence over the value in Other.LI. + LIS->pruneValue(&Other.LI, Def, &EndPoints); + DEBUG(dbgs() << "\t\tpruned " << PrintReg(Other.LI.reg) << " at " << Def + << ": " << Other.LI << '\n'); + break; + case CR_Erase: + case CR_Merge: + if (isPrunedValue(i, Other)) { + // This value is ultimately a copy of a pruned value in LI or Other.LI. + // We can no longer trust the value mapping computed by + // computeAssignment(), the value that was originally copied could have + // been replaced. + LIS->pruneValue(&LI, Def, &EndPoints); + DEBUG(dbgs() << "\t\tpruned all of " << PrintReg(LI.reg) << " at " + << Def << ": " << LI << '\n'); + } + break; + case CR_Unresolved: + case CR_Impossible: + llvm_unreachable("Unresolved conflicts"); + } } } |