1/* Header file for SSA loop optimizations.
2   Copyright (C) 2013-2015 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3.  If not see
18<http://www.gnu.org/licenses/>.  */
19
20#ifndef GCC_TREE_SSA_LOOP_H
21#define GCC_TREE_SSA_LOOP_H
22
23#include "wide-int.h"
24
25/* Affine iv.  */
26
27struct affine_iv
28{
29  /* Iv = BASE + STEP * i.  */
30  tree base, step;
31
32  /* True if this iv does not overflow.  */
33  bool no_overflow;
34};
35
36/* Description of number of iterations of a loop.  All the expressions inside
37   the structure can be evaluated at the end of the loop's preheader
38   (and due to ssa form, also anywhere inside the body of the loop).  */
39
40struct tree_niter_desc
41{
42  tree assumptions;	/* The boolean expression.  If this expression evaluates
43			   to false, then the other fields in this structure
44			   should not be used; there is no guarantee that they
45			   will be correct.  */
46  tree may_be_zero;	/* The boolean expression.  If it evaluates to true,
47			   the loop will exit in the first iteration (i.e.
48			   its latch will not be executed), even if the niter
49			   field says otherwise.  */
50  tree niter;		/* The expression giving the number of iterations of
51			   a loop (provided that assumptions == true and
52			   may_be_zero == false), more precisely the number
53			   of executions of the latch of the loop.  */
54  widest_int max;	/* The upper bound on the number of iterations of
55			   the loop.  */
56
57  /* The simplified shape of the exit condition.  The loop exits if
58     CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
59     LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
60     LE_EXPR and negative if CMP is GE_EXPR.  This information is used
61     by loop unrolling.  */
62  affine_iv control;
63  tree bound;
64  enum tree_code cmp;
65};
66
67extern bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
68extern char *get_lsm_tmp_name (tree ref, unsigned n, const char *suffix = NULL);
69extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights_d *);
70
71/* Returns the loop of the statement STMT.  */
72
73static inline struct loop *
74loop_containing_stmt (gimple stmt)
75{
76  basic_block bb = gimple_bb (stmt);
77  if (!bb)
78    return NULL;
79
80  return bb->loop_father;
81}
82
83#endif /* GCC_TREE_SSA_LOOP_H */
84