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1 #ifndef ISL_AST_BUILD_PRIVATE_H
2 #define ISL_AST_BUILD_PRIVATE_H
4 #include <isl/aff.h>
5 #include <isl/ast.h>
6 #include <isl/ast_build.h>
7 #include <isl/set.h>
8 #include <isl/list.h>
11 atomic,
12 unroll,
13 separate
14 };
16 /* An isl_ast_build represents the context in which AST is being
17 * generated. That is, it (mostly) contains information about outer
18 * loops that can be used to simplify inner loops.
19 *
20 * "domain" represents constraints on the internal schedule domain,
21 * corresponding to the context of the AST generation and the constraints
22 * implied by the loops that have already been generated.
23 * When an isl_ast_build is first created, outside any AST generation,
24 * the domain is typically a parameter set. It is only when a AST
25 * generation phase is initiated that the domain of the isl_ast_build
26 * is changed to refer to the internal schedule domain.
27 * The domain then lives in a space of the form
28 *
29 * S
30 *
31 * or
32 *
33 * [O -> S]
34 *
35 * O represents the loops generated in outer AST generations.
36 * S represents the loops (both generated and to be generated)
37 * of the current AST generation.
38 * Both include eliminated loops.
39 * "domain" is expected not to have any unknown divs because
40 * it is used as the context argument in a call to isl_basic_set_gist
41 * in isl_ast_build_compute_gist_basic_set.
42 *
43 * "depth" is equal to the number of loops that have already
44 * been generated (including those in outer AST generations).
45 * "outer_pos" is equal to the number of loops in outer AST generations.
46 *
47 * "generated" is a superset of "domain" corresponding to those
48 * constraints that were either given by the user or that have
49 * effectively been generated (as bounds on a for loop).
50 *
51 * "pending" is a superset of "domain" corresponding to the constraints
52 * that still need to be generated (as guards), but that may end up
53 * not getting generated if they are implied by any constraints
54 * enforced by inner loops.
55 *
56 * "strides" contains the stride of each loop. The number of elements
57 * is equal to the number of dimensions in "domain".
58 * "offsets" constains the offsets of strided loops. If s is the stride
59 * for a given dimension and f is the corresponding offset, then the
60 * dimension takes on values
61 *
62 * f + s a
63 *
64 * with a an integer. For non-strided loops, the offset is zero.
65 *
66 * "iterators" contains the loop iterators of both generated and
67 * to be generated loops. The number of elements is at least as
68 * large as the dimension of the internal schedule domain. The
69 * number may be larger, in which case the additional ids can be
70 * used in a nested AST generation should the schedule be non-injective.
71 *
72 * "values" lives in the space
73 *
74 * [O -> S] -> [O -> S] (or S -> S)
75 *
76 * and expresses (if possible) loop iterators in terms of parameters
77 * and outer loop iterators. If the value of a given loop iterator
78 * cannot be expressed as an affine expression (either because the iterator
79 * attains multiple values or because the single value is a piecewise
80 * affine expression), then it is expressed in "values" as being equal
81 * to itself.
82 *
83 * "value" is the value of the loop iterator at the current depth.
84 * It is NULL if it has not been computed yet or if the value of the
85 * given loop iterator cannot be expressed as a piecewise affine expression
86 * (because the iterator attains multiple values).
87 *
88 * "schedule_map" maps the internal schedule domain to the external schedule
89 * domain. It may be NULL if it hasn't been computed yet.
90 * See isl_ast_build_get_schedule_map_multi_aff.
91 *
92 * The "create_leaf" callback is called for every leaf in the generated AST.
93 * The callback is responsible for creating the node to be placed at those
94 * leaves. If this callback is not set, then isl will generated user
95 * nodes with call expressions corresponding to an element of the domain.
96 *
97 * The "at_each_domain" callback is called on every node created to represent
98 * an element of the domain. Each of these nodes is a user node
99 * with as expression a call expression.
100 *
101 * The "before_each_for" callback is called on each for node before
102 * its children have been created.
103 *
104 * The "after_each_for" callback is called on each for node after
105 * its children have been created.
106 *
107 * "executed" contains the inverse schedule at this point
108 * of the AST generation.
109 * It is currently only used in isl_ast_build_get_schedule, which is
110 * in turn only used by user code from within a callback.
111 * The value is set right before we may be calling such a callback.
112 *
113 * "single_valued" is set if the current inverse schedule (which may or may
114 * not be stored in "executed") is known to be single valued, specifically
115 * an inverse schedule that was not (appeared not to be) single valued
116 * is extended to a single valued inverse schedule. This is mainly used
117 * to avoid an infinite recursion when we fail to detect later on that
118 * the extended inverse schedule is single valued.
119 */
161 };
267 #endif