1 //===---- LatencyPriorityQueue.h - A latency-oriented priority queue ------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file declares the LatencyPriorityQueue class, which is a 11 // SchedulingPriorityQueue that schedules using latency information to 12 // reduce the length of the critical path through the basic block. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_CODEGEN_LATENCYPRIORITYQUEUE_H 17 #define LLVM_CODEGEN_LATENCYPRIORITYQUEUE_H 18 19 #include "llvm/CodeGen/ScheduleDAG.h" 20 21 namespace llvm { 22 class LatencyPriorityQueue; 23 24 /// Sorting functions for the Available queue. 25 struct latency_sort { 26 LatencyPriorityQueue *PQ; 27 explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {} 28 29 bool operator()(const SUnit* left, const SUnit* right) const; 30 }; 31 32 class LatencyPriorityQueue : public SchedulingPriorityQueue { 33 // SUnits - The SUnits for the current graph. 34 std::vector<SUnit> *SUnits; 35 36 /// NumNodesSolelyBlocking - This vector contains, for every node in the 37 /// Queue, the number of nodes that the node is the sole unscheduled 38 /// predecessor for. This is used as a tie-breaker heuristic for better 39 /// mobility. 40 std::vector<unsigned> NumNodesSolelyBlocking; 41 42 /// Queue - The queue. 43 std::vector<SUnit*> Queue; 44 latency_sort Picker; 45 46 public: 47 LatencyPriorityQueue() : Picker(this) { 48 } 49 50 bool isBottomUp() const override { return false; } 51 52 void initNodes(std::vector<SUnit> &sunits) override { 53 SUnits = &sunits; 54 NumNodesSolelyBlocking.resize(SUnits->size(), 0); 55 } 56 57 void addNode(const SUnit *SU) override { 58 NumNodesSolelyBlocking.resize(SUnits->size(), 0); 59 } 60 61 void updateNode(const SUnit *SU) override { 62 } 63 64 void releaseState() override { 65 SUnits = nullptr; 66 } 67 68 unsigned getLatency(unsigned NodeNum) const { 69 assert(NodeNum < (*SUnits).size()); 70 return (*SUnits)[NodeNum].getHeight(); 71 } 72 73 unsigned getNumSolelyBlockNodes(unsigned NodeNum) const { 74 assert(NodeNum < NumNodesSolelyBlocking.size()); 75 return NumNodesSolelyBlocking[NodeNum]; 76 } 77 78 bool empty() const override { return Queue.empty(); } 79 80 void push(SUnit *U) override; 81 82 SUnit *pop() override; 83 84 void remove(SUnit *SU) override; 85 86 // scheduledNode - As nodes are scheduled, we look to see if there are any 87 // successor nodes that have a single unscheduled predecessor. If so, that 88 // single predecessor has a higher priority, since scheduling it will make 89 // the node available. 90 void scheduledNode(SUnit *Node) override; 91 92 private: 93 void AdjustPriorityOfUnscheduledPreds(SUnit *SU); 94 SUnit *getSingleUnscheduledPred(SUnit *SU); 95 }; 96 } 97 98 #endif 99
