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