/*
 * Copyright (c) 2015, Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
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 *    this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *  * Neither the name of Intel Corporation nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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/** \file
 * \brief Edge redundancy graph reductions.
 */
#ifndef NG_EDGE_REDUNDANCY_H
#define NG_EDGE_REDUNDANCY_H

#include "som/som.h"

namespace ue2 {

class NGHolder;
struct CompileContext;

/** \brief Entry point: Runs all the edge redundancy passes. */
bool removeEdgeRedundancy(NGHolder &g, som_type som, const CompileContext &cc);

/** \brief Removes optional stuff from the front of floating patterns, since
 * it's redundant with startDs.
 *
 * For each successor of startDs, remove any in-edges that aren't from either
 * start or startDs. This allows us to prune redundant vertices at the start of
 * a pattern:
 *
 *     /(hat)?stand --> /stand/
 *
 */
bool removeSiblingsOfStartDotStar(NGHolder &g);

/** \brief Removes all edges into virtual starts other than those from
 * start/startDs, providing there is an edge from startDs.
 *
 * This operation is an optimisation for SOM mode. (see UE-1544) */
bool optimiseVirtualStarts(NGHolder &g);

} // namespace ue2

#endif
