1 //===---- LatencyPriorityQueue.h - A latency-oriented priority queue ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_CODEGEN_LATENCYPRIORITYQUEUE_H
17 #define LLVM_CODEGEN_LATENCYPRIORITYQUEUE_H
19 #include "llvm/CodeGen/ScheduleDAG.h"
20 #include "llvm/Config/llvm-config.h"
23 class LatencyPriorityQueue;
25 /// Sorting functions for the Available queue.
27 LatencyPriorityQueue *PQ;
28 explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {}
30 bool operator()(const SUnit* LHS, const SUnit* RHS) const;
33 class LatencyPriorityQueue : public SchedulingPriorityQueue {
34 // SUnits - The SUnits for the current graph.
35 std::vector<SUnit> *SUnits;
37 /// NumNodesSolelyBlocking - This vector contains, for every node in the
38 /// Queue, the number of nodes that the node is the sole unscheduled
39 /// predecessor for. This is used as a tie-breaker heuristic for better
41 std::vector<unsigned> NumNodesSolelyBlocking;
43 /// Queue - The queue.
44 std::vector<SUnit*> Queue;
48 LatencyPriorityQueue() : Picker(this) {
51 bool isBottomUp() const override { return false; }
53 void initNodes(std::vector<SUnit> &sunits) override {
55 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
58 void addNode(const SUnit *SU) override {
59 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
62 void updateNode(const SUnit *SU) override {
65 void releaseState() override {
69 unsigned getLatency(unsigned NodeNum) const {
70 assert(NodeNum < (*SUnits).size());
71 return (*SUnits)[NodeNum].getHeight();
74 unsigned getNumSolelyBlockNodes(unsigned NodeNum) const {
75 assert(NodeNum < NumNodesSolelyBlocking.size());
76 return NumNodesSolelyBlocking[NodeNum];
79 bool empty() const override { return Queue.empty(); }
81 void push(SUnit *U) override;
83 SUnit *pop() override;
85 void remove(SUnit *SU) override;
87 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
88 LLVM_DUMP_METHOD void dump(ScheduleDAG *DAG) const override;
91 // scheduledNode - As nodes are scheduled, we look to see if there are any
92 // successor nodes that have a single unscheduled predecessor. If so, that
93 // single predecessor has a higher priority, since scheduling it will make
94 // the node available.
95 void scheduledNode(SUnit *SU) override;
98 void AdjustPriorityOfUnscheduledPreds(SUnit *SU);
99 SUnit *getSingleUnscheduledPred(SUnit *SU);