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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>
12 atomic,
13 unroll,
14 separate
15 };
17 /* An isl_ast_build represents the context in which AST is being
18 * generated. That is, it (mostly) contains information about outer
19 * loops that can be used to simplify inner loops.
20 *
21 * "domain" represents constraints on the internal schedule domain,
22 * corresponding to the context of the AST generation and the constraints
23 * implied by the loops that have already been generated.
24 * When an isl_ast_build is first created, outside any AST generation,
25 * the domain is typically a parameter set. It is only when a AST
26 * generation phase is initiated that the domain of the isl_ast_build
27 * is changed to refer to the internal schedule domain.
28 * The domain then lives in a space of the form
29 *
30 * S
31 *
32 * or
33 *
34 * [O -> S]
35 *
36 * O represents the loops generated in outer AST generations.
37 * S represents the loops (both generated and to be generated)
38 * of the current AST generation.
39 * Both include eliminated loops.
40 * "domain" is expected not to have any unknown divs because
41 * it is used as the context argument in a call to isl_basic_set_gist
42 * in isl_ast_build_compute_gist_basic_set.
43 *
44 * "depth" is equal to the number of loops that have already
45 * been generated (including those in outer AST generations).
46 * "outer_pos" is equal to the number of loops in outer AST generations.
47 *
48 * "generated" is a superset of "domain" corresponding to those
49 * constraints that were either given by the user or that have
50 * effectively been generated (as bounds on a for loop).
51 *
52 * "pending" is a superset of "domain" corresponding to the constraints
53 * that still need to be generated (as guards), but that may end up
54 * not getting generated if they are implied by any constraints
55 * enforced by inner loops.
56 *
57 * "strides" contains the stride of each loop. The number of elements
58 * is equal to the number of dimensions in "domain".
59 * "offsets" constains the offsets of strided loops. If s is the stride
60 * for a given dimension and f is the corresponding offset, then the
61 * dimension takes on values
62 *
63 * f + s a
64 *
65 * with a an integer. For non-strided loops, the offset is zero.
66 *
67 * "iterators" contains the loop iterators of both generated and
68 * to be generated loops. The number of elements is at least as
69 * large as the dimension of the internal schedule domain. The
70 * number may be larger, in which case the additional ids can be
71 * used in a nested AST generation should the schedule be non-injective.
72 *
73 * "values" lives in the space
74 *
75 * [O -> S] -> [O -> S] (or S -> S)
76 *
77 * and expresses (if possible) loop iterators in terms of parameters
78 * and outer loop iterators. If the value of a given loop iterator
79 * cannot be expressed as an affine expression (either because the iterator
80 * attains multiple values or because the single value is a piecewise
81 * affine expression), then it is expressed in "values" as being equal
82 * to itself.
83 *
84 * "value" is the value of the loop iterator at the current depth.
85 * It is NULL if it has not been computed yet or if the value of the
86 * given loop iterator cannot be expressed as a piecewise affine expression
87 * (because the iterator attains multiple values).
88 *
89 * "schedule_map" maps the internal schedule domain to the external schedule
90 * domain. It may be NULL if it hasn't been computed yet.
91 * See isl_ast_build_get_schedule_map_multi_aff.
92 *
93 * "options" contains the AST build options in case we are generating
94 * an AST from a flat schedule map. When creating an AST from a schedule
95 * tree, this field is ignored.
96 *
97 * The "create_leaf" callback is called for every leaf in the generated AST.
98 * The callback is responsible for creating the node to be placed at those
99 * leaves. If this callback is not set, then isl will generated user
100 * nodes with call expressions corresponding to an element of the domain.
101 *
102 * The "at_each_domain" callback is called on every node created to represent
103 * an element of the domain. Each of these nodes is a user node
104 * with as expression a call expression.
105 *
106 * The "before_each_for" callback is called on each for node before
107 * its children have been created.
108 *
109 * The "after_each_for" callback is called on each for node after
110 * its children have been created.
111 *
112 * "executed" contains the inverse schedule at this point
113 * of the AST generation.
114 * It is currently only used in isl_ast_build_get_schedule, which is
115 * in turn only used by user code from within a callback.
116 * The value is set right before we may be calling such a callback.
117 *
118 * "single_valued" is set if the current inverse schedule (which may or may
119 * not be stored in "executed") is known to be single valued, specifically
120 * an inverse schedule that was not (appeared not to be) single valued
121 * is extended to a single valued inverse schedule. This is mainly used
122 * to avoid an infinite recursion when we fail to detect later on that
123 * the extended inverse schedule is single valued.
124 *
125 * "node" points to the current band node in case we are generating
126 * an AST from a schedule tree. It may be NULL if we are not generating
127 * an AST from a schedule tree or if we are not inside a band node.
128 */
172 };
287 #endif