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//===---- LatencyPriorityQueue.h - A latency-oriented priority queue ------===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file declares the LatencyPriorityQueue class, which is a
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// SchedulingPriorityQueue that schedules using latency information to
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// reduce the length of the critical path through the basic block.
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//===----------------------------------------------------------------------===//
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#ifndef LATENCY_PRIORITY_QUEUE_H
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#define LATENCY_PRIORITY_QUEUE_H
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#include "llvm/CodeGen/ScheduleDAG.h"
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class LatencyPriorityQueue;
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/// Sorting functions for the Available queue.
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struct latency_sort : public std::binary_function<SUnit*, SUnit*, bool> {
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LatencyPriorityQueue *PQ;
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explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {}
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bool operator()(const SUnit* left, const SUnit* right) const;
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class LatencyPriorityQueue : public SchedulingPriorityQueue {
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// SUnits - The SUnits for the current graph.
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std::vector<SUnit> *SUnits;
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/// NumNodesSolelyBlocking - This vector contains, for every node in the
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/// Queue, the number of nodes that the node is the sole unscheduled
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/// predecessor for. This is used as a tie-breaker heuristic for better
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std::vector<unsigned> NumNodesSolelyBlocking;
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/// Queue - The queue.
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std::vector<SUnit*> Queue;
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LatencyPriorityQueue() : Picker(this) {
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void initNodes(std::vector<SUnit> &sunits) {
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NumNodesSolelyBlocking.resize(SUnits->size(), 0);
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void addNode(const SUnit *SU) {
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NumNodesSolelyBlocking.resize(SUnits->size(), 0);
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void updateNode(const SUnit *SU) {
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unsigned getLatency(unsigned NodeNum) const {
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assert(NodeNum < (*SUnits).size());
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return (*SUnits)[NodeNum].getHeight();
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unsigned getNumSolelyBlockNodes(unsigned NodeNum) const {
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assert(NodeNum < NumNodesSolelyBlocking.size());
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return NumNodesSolelyBlocking[NodeNum];
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bool empty() const { return Queue.empty(); }
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virtual void push(SUnit *U);
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virtual void remove(SUnit *SU);
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// ScheduledNode - As nodes are scheduled, we look to see if there are any
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// successor nodes that have a single unscheduled predecessor. If so, that
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// single predecessor has a higher priority, since scheduling it will make
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// the node available.
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void ScheduledNode(SUnit *Node);
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void AdjustPriorityOfUnscheduledPreds(SUnit *SU);
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SUnit *getSingleUnscheduledPred(SUnit *SU);