text: /* Scalar evolution detector.
     Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
     Contributed by Sebastian Pop <s.pop@laposte.net>
  
  This file is part of GCC.
  
  GCC is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free
  Software Foundation; either version 3, or (at your option) any later
  version.
  
  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  for more details.
  
  You should have received a copy of the GNU General Public License
  along with GCC; see the file COPYING3.  If not see
  <http://www.gnu.org/licenses/>.  */
  
  #ifndef GCC_TREE_SCALAR_EVOLUTION_H
  #define GCC_TREE_SCALAR_EVOLUTION_H
  
  extern tree number_of_latch_executions (struct loop *);
  extern tree number_of_exit_cond_executions (struct loop *);
  extern gimple get_loop_exit_condition (const struct loop *);
  
  extern void scev_initialize (void);
  extern void scev_reset (void);
  extern void scev_finalize (void);
  extern tree analyze_scalar_evolution (struct loop *, tree);
  extern tree instantiate_scev (basic_block, struct loop *, tree);
  extern tree resolve_mixers (struct loop *, tree);
  extern void gather_stats_on_scev_database (void);
  extern void scev_analysis (void);
  unsigned int scev_const_prop (void);
  
  bool expression_expensive_p (tree);
  extern bool simple_iv (struct loop *, struct loop *, tree, affine_iv *, bool);
  
  /* Returns the basic block preceding LOOP or ENTRY_BLOCK_PTR when the
     loop is function's body.  */
  
  static inline basic_block
  block_before_loop (loop_p loop)
  {
    edge preheader = loop_preheader_edge (loop);
    return (preheader ? preheader->src : ENTRY_BLOCK_PTR);
  }
  
  /* Analyze all the parameters of the chrec that were left under a
     symbolic form.  LOOP is the loop in which symbolic names have to
     be analyzed and instantiated.  */
  
  static inline tree
  instantiate_parameters (struct loop *loop, tree chrec)
  {
    return instantiate_scev (block_before_loop (loop), loop, chrec);
  }
  
  /* Returns the loop of the polynomial chrec CHREC.  */
  
  static inline struct loop *
  get_chrec_loop (const_tree chrec)
  {
    return get_loop (CHREC_VARIABLE (chrec));
  }
  
  #endif  /* GCC_TREE_SCALAR_EVOLUTION_H  */
  