1/* Header file for SSA loop optimizations.
2 Copyright (C) 2013-2017 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
24/* Affine iv. */
25
26struct affine_iv
27{
28 /* Iv = BASE + STEP * i. */
29 tree base, step;
30
31 /* True if this iv does not overflow. */
32 bool no_overflow;
33};
34
35/* Description of number of iterations of a loop. All the expressions inside
36 the structure can be evaluated at the end of the loop's preheader
37 (and due to ssa form, also anywhere inside the body of the loop). */
38
39struct tree_niter_desc
40{
41 tree assumptions; /* The boolean expression. If this expression evaluates
42 to false, then the other fields in this structure
43 should not be used; there is no guarantee that they
44 will be correct. */
45 tree may_be_zero; /* The boolean expression. If it evaluates to true,
46 the loop will exit in the first iteration (i.e.
47 its latch will not be executed), even if the niter
48 field says otherwise. */
49 tree niter; /* The expression giving the number of iterations of
50 a loop (provided that assumptions == true and
51 may_be_zero == false), more precisely the number
52 of executions of the latch of the loop. */
53 widest_int max; /* The upper bound on the number of iterations of
54 the loop. */
55
56 /* The simplified shape of the exit condition. The loop exits if
57 CONTROL CMP BOUND is false, where CMP is one of NE_EXPR,
58 LT_EXPR, or GT_EXPR, and step of CONTROL is positive if CMP is
59 LE_EXPR and negative if CMP is GE_EXPR. This information is used
60 by loop unrolling. */
61 affine_iv control;
62 tree bound;
63 enum tree_code cmp;
64};
65
66extern bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
67extern char *get_lsm_tmp_name (tree ref, unsigned n, const char *suffix = NULL);
68extern unsigned tree_num_loop_insns (struct loop *, struct eni_weights *);
69
70/* Returns the loop of the statement STMT. */
71
72static inline struct loop *
73loop_containing_stmt (gimple *stmt)
74{
75 basic_block bb = gimple_bb (stmt);
76 if (!bb)
77 return NULL;
78
79 return bb->loop_father;
80}
81
82#endif /* GCC_TREE_SSA_LOOP_H */
83