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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>
9 #include <isl/schedule_node.h>
11 /* An isl_ast_build represents the context in which AST is being
12 * generated. That is, it (mostly) contains information about outer
13 * loops that can be used to simplify inner loops.
14 *
15 * "domain" represents constraints on the internal schedule domain,
16 * corresponding to the context of the AST generation and the constraints
17 * implied by the loops that have already been generated.
18 * When an isl_ast_build is first created, outside any AST generation,
19 * the domain is typically a parameter set. It is only when a AST
20 * generation phase is initiated that the domain of the isl_ast_build
21 * is changed to refer to the internal schedule domain.
22 * The domain then lives in a space of the form
23 *
24 * S
25 *
26 * or
27 *
28 * [O -> S]
29 *
30 * O represents the loops generated in outer AST generations.
31 * S represents the loops (both generated and to be generated)
32 * of the current AST generation.
33 * Both include eliminated loops.
34 * "domain" is expected not to have any unknown divs because
35 * it is used as the context argument in a call to isl_basic_set_gist
36 * in isl_ast_build_compute_gist_basic_set.
37 *
38 * "depth" is equal to the number of loops that have already
39 * been generated (including those in outer AST generations).
40 * "outer_pos" is equal to the number of loops in outer AST generations.
41 *
42 * "generated" is a superset of "domain" corresponding to those
43 * constraints that were either given by the user or that have
44 * effectively been generated (as bounds on a for loop).
45 *
46 * "pending" is a superset of "domain" corresponding to the constraints
47 * that still need to be generated (as guards), but that may end up
48 * not getting generated if they are implied by any constraints
49 * enforced by inner loops.
50 *
51 * "strides" contains the stride of each loop. The number of elements
52 * is equal to the number of dimensions in "domain".
53 * "offsets" constains the offsets of strided loops. If s is the stride
54 * for a given dimension and f is the corresponding offset, then the
55 * dimension takes on values
56 *
57 * f + s a
58 *
59 * with a an integer. For non-strided loops, the offset is zero.
60 *
61 * "iterators" contains the loop iterators of both generated and
62 * to be generated loops. The number of elements is at least as
63 * large as the dimension of the internal schedule domain. The
64 * number may be larger, in which case the additional ids can be
65 * used in a nested AST generation should the schedule be non-injective.
66 *
67 * "values" lives in the space
68 *
69 * [O -> S] -> [O -> S] (or S -> S)
70 *
71 * and expresses (if possible) loop iterators in terms of parameters
72 * and outer loop iterators. If the value of a given loop iterator
73 * cannot be expressed as an affine expression (either because the iterator
74 * attains multiple values or because the single value is a piecewise
75 * affine expression), then it is expressed in "values" as being equal
76 * to itself.
77 *
78 * "value" is the value of the loop iterator at the current depth.
79 * It is NULL if it has not been computed yet or if the value of the
80 * given loop iterator cannot be expressed as a piecewise affine expression
81 * (because the iterator attains multiple values).
82 *
83 * "schedule_map" maps the internal schedule domain to the external schedule
84 * domain. It may be NULL if it hasn't been computed yet.
85 * See isl_ast_build_get_schedule_map_multi_aff.
86 *
87 * "internal2input" maps the internal schedule domain to the original
88 * input schedule domain. In case of a schedule tree input, the original
89 * input schedule domain consist of the flat product of all outer
90 * band node spaces, including the current band node.
91 * It may be NULL if there no longer is such a uniform mapping
92 * (because different iterations have been rescheduled differently).
93 *
94 * "options" contains the AST build options in case we are generating
95 * an AST from a flat schedule map. When creating an AST from a schedule
96 * tree, this field is ignored.
97 *
98 * The "create_leaf" callback is called for every leaf in the generated AST.
99 * The callback is responsible for creating the node to be placed at those
100 * leaves. If this callback is not set, then isl will generated user
101 * nodes with call expressions corresponding to an element of the domain.
102 *
103 * The "at_each_domain" callback is called on every node created to represent
104 * an element of the domain. Each of these nodes is a user node
105 * with as expression a call expression.
106 *
107 * The "before_each_for" callback is called on each for node before
108 * its children have been created.
109 *
110 * The "after_each_for" callback is called on each for node after
111 * its children have been created.
112 *
113 * "executed" contains the inverse schedule at this point
114 * of the AST generation.
115 * It is currently only used in isl_ast_build_get_schedule, which is
116 * in turn only used by user code from within a callback.
117 * The value is set right before we may be calling such a callback.
118 *
119 * "single_valued" is set if the current inverse schedule (which may or may
120 * not be stored in "executed") is known to be single valued, specifically
121 * an inverse schedule that was not (appeared not to be) single valued
122 * is extended to a single valued inverse schedule. This is mainly used
123 * to avoid an infinite recursion when we fail to detect later on that
124 * the extended inverse schedule is single valued.
125 *
126 * "node" points to the current band node in case we are generating
127 * an AST from a schedule tree. It may be NULL if we are not generating
128 * an AST from a schedule tree or if we are not inside a band node.
129 *
130 * "loop_type" originally constains loop AST generation types for
131 * the "n" members of "node" and it is updated (along with "n") when
132 * a schedule dimension is inserted.
133 * It is NULL if "node" is NULL.
134 *
135 * "isolated" is the piece of the schedule domain isolated by the isolate
136 * option on the current band. This set may be NULL if we have not checked
137 * for the isolate option yet.
138 */
186 };
311 #endif