diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/MachineOutliner.cpp | 71 | ||||
| -rw-r--r-- | llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll | 4 |
2 files changed, 38 insertions, 37 deletions
diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp index 8a884a1b363..b52d3ebfeff 100644 --- a/llvm/lib/CodeGen/MachineOutliner.cpp +++ b/llvm/lib/CodeGen/MachineOutliner.cpp @@ -146,17 +146,30 @@ struct OutlinedFunction { /// function. std::vector<unsigned> Sequence; - /// The number of instructions this function would save. - unsigned Benefit = 0; - /// Contains all target-specific information for this \p OutlinedFunction. TargetInstrInfo::MachineOutlinerInfo MInfo; + /// \brief Return the number of instructions it would take to outline this + /// function. + unsigned getOutliningCost() { + return (OccurrenceCount * MInfo.CallOverhead) + Sequence.size() + + MInfo.FrameOverhead; + } + + /// \brief Return the number of instructions that would be saved by outlining + /// this function. + unsigned getBenefit() { + unsigned NotOutlinedCost = OccurrenceCount * Sequence.size(); + unsigned OutlinedCost = getOutliningCost(); + return (NotOutlinedCost < OutlinedCost) ? 0 + : NotOutlinedCost - OutlinedCost; + } + OutlinedFunction(unsigned Name, unsigned OccurrenceCount, - const std::vector<unsigned> &Sequence, unsigned Benefit, + const std::vector<unsigned> &Sequence, TargetInstrInfo::MachineOutlinerInfo &MInfo) : Name(Name), OccurrenceCount(OccurrenceCount), Sequence(Sequence), - Benefit(Benefit), MInfo(MInfo) {} + MInfo(MInfo) {} }; /// Represents an undefined index in the suffix tree. @@ -844,7 +857,6 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, std::vector<OutlinedFunction> &FunctionList) { CandidateList.clear(); FunctionList.clear(); - unsigned FnIdx = 0; unsigned MaxLen = 0; // FIXME: Visit internal nodes instead of leaves. @@ -891,7 +903,8 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, MachineBasicBlock::iterator EndIt = Mapper.InstrList[M->SuffixIdx + StringLen - 1]; - CandidatesForRepeatedSeq.emplace_back(M->SuffixIdx, StringLen, FnIdx); + CandidatesForRepeatedSeq.emplace_back(M->SuffixIdx, StringLen, + FunctionList.size()); RepeatedSequenceLocs.emplace_back(std::make_pair(StartIt, EndIt)); // Never visit this leaf again. @@ -899,16 +912,20 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, } } - unsigned SequenceOverhead = StringLen; + // We've found something we might want to outline. + // Create an OutlinedFunction to store it and check if it'd be beneficial + // to outline. TargetInstrInfo::MachineOutlinerInfo MInfo = TII.getOutlininingCandidateInfo(RepeatedSequenceLocs); - - unsigned OutliningCost = - (MInfo.CallOverhead * Parent.OccurrenceCount) + MInfo.FrameOverhead; - unsigned NotOutliningCost = SequenceOverhead * Parent.OccurrenceCount; + std::vector<unsigned> Seq; + for (unsigned i = Leaf->SuffixIdx; i < Leaf->SuffixIdx + StringLen; i++) + Seq.push_back(ST.Str[i]); + OutlinedFunction OF(FunctionList.size(), Parent.OccurrenceCount, Seq, + MInfo); + unsigned Benefit = OF.getBenefit(); // Is it better to outline this candidate than not? - if (NotOutliningCost <= OutliningCost) { + if (Benefit < 1) { // Outlining this candidate would take more instructions than not // outlining. // Emit a remark explaining why we didn't outline this candidate. @@ -923,9 +940,9 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, << " from " << NV("NumOccurrences", RepeatedSequenceLocs.size()) << " locations." << " Instructions from outlining all occurrences (" - << NV("OutliningCost", OutliningCost) << ")" + << NV("OutliningCost", OF.getOutliningCost()) << ")" << " >= Unoutlined instruction count (" - << NV("NotOutliningCost", NotOutliningCost) << ")" + << NV("NotOutliningCost", StringLen * OF.OccurrenceCount) << ")" << " (Also found at: "; // Tell the user the other places the candidate was found. @@ -943,8 +960,6 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, continue; } - unsigned Benefit = NotOutliningCost - OutliningCost; - if (StringLen > MaxLen) MaxLen = StringLen; @@ -956,16 +971,9 @@ MachineOutliner::findCandidates(SuffixTree &ST, const TargetInstrInfo &TII, CandidateList.push_back(C); } - // Save the function for the new candidate sequence. - std::vector<unsigned> CandidateSequence; - for (unsigned i = Leaf->SuffixIdx; i < Leaf->SuffixIdx + StringLen; i++) - CandidateSequence.push_back(ST.Str[i]); - - FunctionList.emplace_back(FnIdx, CandidatesForRepeatedSeq.size(), - CandidateSequence, Benefit, MInfo); + FunctionList.push_back(OF); // Move to the next function. - FnIdx++; Parent.IsInTree = false; } @@ -990,7 +998,7 @@ void MachineOutliner::pruneOverlaps(std::vector<Candidate> &CandidateList, // pruning steps. OutlinedFunction &F = FunctionList[C.FunctionIdx]; - if (F.OccurrenceCount < 2 || F.Benefit < 1) { + if (F.OccurrenceCount < 2 || F.getBenefit() < 1) { assert(F.OccurrenceCount > 0 && "Can't remove OutlinedFunction with no occurrences!"); F.OccurrenceCount--; @@ -1013,20 +1021,13 @@ void MachineOutliner::pruneOverlaps(std::vector<Candidate> &CandidateList, "Can't remove OutlinedFunction with no occurrences!"); F.OccurrenceCount--; - // Remove the call overhead from the removed sequence. - F.Benefit += C.MInfo.CallOverhead; - - // Add back one instance of the sequence. - F.Benefit = - (F.Sequence.size() > F.Benefit) ? 0 : F.Benefit - F.Sequence.size(); - // Remove C from the CandidateList. C.InCandidateList = false; DEBUG(dbgs() << "- Removed a Candidate \n"; dbgs() << "--- Num fns left for candidate: " << F.OccurrenceCount << "\n"; - dbgs() << "--- Candidate's functions's benefit: " << F.Benefit + dbgs() << "--- Candidate's functions's benefit: " << F.getBenefit() << "\n";); }; @@ -1187,7 +1188,7 @@ bool MachineOutliner::outline(Module &M, OutlinedFunction &OF = FunctionList[C.FunctionIdx]; // Was its OutlinedFunction made unbeneficial during pruneOverlaps? - if (OF.OccurrenceCount < 2 || OF.Benefit < 1) + if (OF.OccurrenceCount < 2 || OF.getBenefit() < 1) continue; // If not, then outline it. diff --git a/llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll b/llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll index 7f3a4f4d494..113f3431101 100644 --- a/llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll +++ b/llvm/test/CodeGen/AArch64/machine-outliner-remarks.ll @@ -1,7 +1,7 @@ ; RUN: llc %s -enable-machine-outliner -mtriple=aarch64-unknown-unknown -pass-remarks-missed=machine-outliner -o /dev/null 2>&1 | FileCheck %s ; CHECK: machine-outliner-remarks.ll:5:9: ; CHECK-SAME: Did not outline 2 instructions from 2 locations. -; CHECK-SAME: Instructions from outlining all occurrences (7) >= +; CHECK-SAME: Instructions from outlining all occurrences (9) >= ; CHECK-SAME: Unoutlined instruction count (4) ; CHECK-SAME: (Also found at: machine-outliner-remarks.ll:13:9) ; RUN: llc %s -enable-machine-outliner -mtriple=aarch64-unknown-unknown -o /dev/null -pass-remarks-missed=machine-outliner -pass-remarks-output=%t.yaml @@ -19,7 +19,7 @@ ; YAML-NEXT: - NumOccurrences: '2' ; YAML-NEXT: - String: ' locations.' ; YAML-NEXT: - String: ' Instructions from outlining all occurrences (' -; YAML-NEXT: - OutliningCost: '7' +; YAML-NEXT: - OutliningCost: '9' ; YAML-NEXT: - String: ')' ; YAML-NEXT: - String: ' >= Unoutlined instruction count (' ; YAML-NEXT: - NotOutliningCost: '4' |
