diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp | 58 |
1 files changed, 41 insertions, 17 deletions
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp index d09622fd6b..d686267e40 100644 --- a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp +++ b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp @@ -33,6 +33,13 @@ using namespace llvm; namespace { + // TEMPORARY option to test a fix. + cl::opt<bool> + SchedIgnorStore("sched-ignore-store", cl::Hidden); + +} + +namespace { Statistic<> NumNoops ("scheduler", "Number of noops inserted"); Statistic<> NumStalls("scheduler", "Number of pipeline stalls"); @@ -51,6 +58,7 @@ namespace { short NumSuccsLeft; // # of succs not scheduled. short NumChainPredsLeft; // # of chain preds not scheduled. short NumChainSuccsLeft; // # of chain succs not scheduled. + bool isStore : 1; // Is a store. bool isTwoAddress : 1; // Is a two-address instruction. bool isDefNUseOperand : 1; // Is a def&use operand. bool isPending : 1; // True once pending. @@ -63,7 +71,7 @@ namespace { SUnit(SDNode *node, unsigned nodenum) : Node(node), NumPredsLeft(0), NumSuccsLeft(0), - NumChainPredsLeft(0), NumChainSuccsLeft(0), + NumChainPredsLeft(0), NumChainSuccsLeft(0), isStore(false), isTwoAddress(false), isDefNUseOperand(false), isPending(false), isAvailable(false), isScheduled(false), Latency(0), CycleBound(0), Cycle(0), NodeNum(nodenum) {} @@ -315,9 +323,14 @@ void ScheduleDAGList::BuildSchedUnits() { SUnit *SU = &SUnits[su]; SDNode *MainNode = SU->Node; - if (MainNode->isTargetOpcode() && - TII->isTwoAddrInstr(MainNode->getTargetOpcode())) - SU->isTwoAddress = true; + if (MainNode->isTargetOpcode()) { + unsigned Opc = MainNode->getTargetOpcode(); + if (TII->isTwoAddrInstr(Opc)) + SU->isTwoAddress = true; + if (TII->isStore(Opc)) + if (!SchedIgnorStore) + SU->isStore = true; + } // Find all predecessors and successors of the group. // Temporarily add N to make code simpler. @@ -358,9 +371,9 @@ void ScheduleDAGList::BuildSchedUnits() { SU->FlaggedNodes.pop_back(); } - return; DEBUG(for (unsigned su = 0, e = SUnits.size(); su != e; ++su) SUnits[su].dumpAll(&DAG)); + return; } /// EmitSchedule - Emit the machine code in scheduled order. @@ -735,7 +748,7 @@ namespace { const std::vector<SUnit> *SUnits; // SethiUllmanNumbers - The SethiUllman number for each node. - std::vector<int> SethiUllmanNumbers; + std::vector<unsigned> SethiUllmanNumbers; std::priority_queue<SUnit*, std::vector<SUnit*>, ls_rr_sort> Queue; public: @@ -774,7 +787,7 @@ namespace { } private: void CalculatePriorities(); - int CalcNodePriority(const SUnit *SU); + unsigned CalcNodePriority(const SUnit *SU); }; } @@ -784,7 +797,7 @@ bool ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const { int LBonus = (int)left ->isDefNUseOperand; int RBonus = (int)right->isDefNUseOperand; - + // Special tie breaker: if two nodes share a operand, the one that // use it as a def&use operand is preferred. if (left->isTwoAddress && !right->isTwoAddress) { @@ -798,6 +811,20 @@ bool ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const { RBonus++; } + // Push stores up as much as possible. This really help code like this: + // load + // compute + // store + // load + // compute + // store + // This would make sure the scheduled code completed all computations and + // the stores before the next series of computation starts. + if (!left->isStore && right->isStore) + LBonus += 2; + if (left->isStore && !right->isStore) + RBonus += 2; + // Priority1 is just the number of live range genned. int LPriority1 = left ->NumPredsLeft - LBonus; int RPriority1 = right->NumPredsLeft - RBonus; @@ -819,9 +846,9 @@ bool ls_rr_sort::operator()(const SUnit *left, const SUnit *right) const { /// CalcNodePriority - Priority is the Sethi Ullman number. /// Smaller number is the higher priority. -int RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { - int &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum]; - if (SethiUllmanNumber != INT_MIN) +unsigned RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { + unsigned &SethiUllmanNumber = SethiUllmanNumbers[SU->NodeNum]; + if (SethiUllmanNumber != 0) return SethiUllmanNumber; if (SU->Preds.size() == 0) { @@ -832,7 +859,7 @@ int RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { I = SU->Preds.begin(), E = SU->Preds.end(); I != E; ++I) { if (I->second) continue; // ignore chain preds. SUnit *PredSU = I->first; - int PredSethiUllman = CalcNodePriority(PredSU); + unsigned PredSethiUllman = CalcNodePriority(PredSU); if (PredSethiUllman > SethiUllmanNumber) { SethiUllmanNumber = PredSethiUllman; Extra = 0; @@ -840,10 +867,7 @@ int RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { Extra++; } - if (SU->Node->getOpcode() != ISD::TokenFactor) - SethiUllmanNumber += Extra; - else - SethiUllmanNumber = (Extra == 1) ? 0 : Extra-1; + SethiUllmanNumber += Extra; } return SethiUllmanNumber; @@ -851,7 +875,7 @@ int RegReductionPriorityQueue::CalcNodePriority(const SUnit *SU) { /// CalculatePriorities - Calculate priorities of all scheduling units. void RegReductionPriorityQueue::CalculatePriorities() { - SethiUllmanNumbers.assign(SUnits->size(), INT_MIN); + SethiUllmanNumbers.assign(SUnits->size(), 0); for (unsigned i = 0, e = SUnits->size(); i != e; ++i) CalcNodePriority(&(*SUnits)[i]); |