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 LATENCY_PRIORITY_QUEUE_H
17 #define LATENCY_PRIORITY_QUEUE_H
19 #include "llvm/CodeGen/ScheduleDAG.h"
20 #include "llvm/ADT/PriorityQueue.h"
23 class LatencyPriorityQueue;
25 /// Sorting functions for the Available queue.
26 struct latency_sort : public std::binary_function<SUnit*, SUnit*, bool> {
27 LatencyPriorityQueue *PQ;
28 explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {}
30 bool operator()(const SUnit* left, const SUnit* right) 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 PriorityQueue<SUnit*, std::vector<SUnit*>, latency_sort> Queue;
45 LatencyPriorityQueue() : Queue(latency_sort(this)) {
48 void initNodes(std::vector<SUnit> &sunits) {
50 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
53 void addNode(const SUnit *SU) {
54 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
57 void updateNode(const SUnit *SU) {
64 unsigned getLatency(unsigned NodeNum) const {
65 assert(NodeNum < (*SUnits).size());
66 return (*SUnits)[NodeNum].getHeight();
69 unsigned getNumSolelyBlockNodes(unsigned NodeNum) const {
70 assert(NodeNum < NumNodesSolelyBlocking.size());
71 return NumNodesSolelyBlocking[NodeNum];
74 unsigned size() const { return Queue.size(); }
76 bool empty() const { return Queue.empty(); }
78 virtual void push(SUnit *U) {
81 void push_impl(SUnit *U);
83 void push_all(const std::vector<SUnit *> &Nodes) {
84 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
89 if (empty()) return NULL;
90 SUnit *V = Queue.top();
95 void remove(SUnit *SU) {
96 assert(!Queue.empty() && "Not in queue!");
100 // ScheduledNode - As nodes are scheduled, we look to see if there are any
101 // successor nodes that have a single unscheduled predecessor. If so, that
102 // single predecessor has a higher priority, since scheduling it will make
103 // the node available.
104 void ScheduledNode(SUnit *Node);
107 void AdjustPriorityOfUnscheduledPreds(SUnit *SU);
108 SUnit *getSingleUnscheduledPred(SUnit *SU);