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"
22 class LatencyPriorityQueue;
24 /// Sorting functions for the Available queue.
25 struct latency_sort : public std::binary_function<SUnit*, SUnit*, bool> {
26 LatencyPriorityQueue *PQ;
27 explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {}
29 bool operator()(const SUnit* left, const SUnit* right) const;
32 class LatencyPriorityQueue : public SchedulingPriorityQueue {
33 // SUnits - The SUnits for the current graph.
34 std::vector<SUnit> *SUnits;
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
40 std::vector<unsigned> NumNodesSolelyBlocking;
42 /// Queue - The queue.
43 std::vector<SUnit*> Queue;
47 LatencyPriorityQueue() : Picker(this) {
50 void initNodes(std::vector<SUnit> &sunits) {
52 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
55 void addNode(const SUnit *SU) {
56 NumNodesSolelyBlocking.resize(SUnits->size(), 0);
59 void updateNode(const SUnit *SU) {
66 unsigned getLatency(unsigned NodeNum) const {
67 assert(NodeNum < (*SUnits).size());
68 return (*SUnits)[NodeNum].getHeight();
71 unsigned getNumSolelyBlockNodes(unsigned NodeNum) const {
72 assert(NodeNum < NumNodesSolelyBlocking.size());
73 return NumNodesSolelyBlocking[NodeNum];
76 bool empty() const { return Queue.empty(); }
78 virtual void push(SUnit *U);
82 virtual void remove(SUnit *SU);
84 // ScheduledNode - As nodes are scheduled, we look to see if there are any
85 // successor nodes that have a single unscheduled predecessor. If so, that
86 // single predecessor has a higher priority, since scheduling it will make
87 // the node available.
88 void ScheduledNode(SUnit *Node);
91 void AdjustPriorityOfUnscheduledPreds(SUnit *SU);
92 SUnit *getSingleUnscheduledPred(SUnit *SU);