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llvm-mirror/include/llvm/CodeGen/LatencyPriorityQueue.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

103 lines
3.1 KiB
C++

//===---- LatencyPriorityQueue.h - A latency-oriented priority queue ------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// 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"
#include "llvm/Config/llvm-config.h"
namespace llvm {
class LatencyPriorityQueue;
/// Sorting functions for the Available queue.
struct latency_sort {
LatencyPriorityQueue *PQ;
explicit latency_sort(LatencyPriorityQueue *pq) : PQ(pq) {}
bool operator()(const SUnit* LHS, const SUnit* RHS) 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;
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void dump(ScheduleDAG *DAG) const override;
#endif
// 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 *SU) override;
private:
void AdjustPriorityOfUnscheduledPreds(SUnit *SU);
SUnit *getSingleUnscheduledPred(SUnit *SU);
};
}
#endif