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f6c72af4 | 1 | /* Header file for SSA dominator optimizations. |
a945c346 | 2 | Copyright (C) 2013-2024 Free Software Foundation, Inc. |
f6c72af4 JL |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it under | |
7 | the terms of the GNU General Public License as published by the Free | |
8 | Software Foundation; either version 3, or (at your option) any later | |
9 | version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 | for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GCC; see the file COPYING3. If not see | |
18 | <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #ifndef GCC_TREE_SSA_SCOPED_TABLES_H | |
21 | #define GCC_TREE_SSA_SCOPED_TABLES_H | |
22 | ||
d3139801 JL |
23 | /* Representation of a "naked" right-hand-side expression, to be used |
24 | in recording available expressions in the expression hash table. */ | |
25 | ||
26 | enum expr_kind | |
27 | { | |
28 | EXPR_SINGLE, | |
29 | EXPR_UNARY, | |
30 | EXPR_BINARY, | |
31 | EXPR_TERNARY, | |
32 | EXPR_CALL, | |
33 | EXPR_PHI | |
34 | }; | |
35 | ||
36 | struct hashable_expr | |
37 | { | |
38 | tree type; | |
39 | enum expr_kind kind; | |
40 | union { | |
41 | struct { tree rhs; } single; | |
42 | struct { enum tree_code op; tree opnd; } unary; | |
43 | struct { enum tree_code op; tree opnd0, opnd1; } binary; | |
44 | struct { enum tree_code op; tree opnd0, opnd1, opnd2; } ternary; | |
45 | struct { gcall *fn_from; bool pure; size_t nargs; tree *args; } call; | |
46 | struct { size_t nargs; tree *args; } phi; | |
47 | } ops; | |
48 | }; | |
49 | ||
a3d514f2 JL |
50 | /* Structure for recording known value of a conditional expression. |
51 | ||
52 | Clients build vectors of these objects to record known values | |
53 | that occur on edges. */ | |
54 | ||
55 | struct cond_equivalence | |
56 | { | |
57 | /* The condition, in a HASHABLE_EXPR form. */ | |
58 | struct hashable_expr cond; | |
59 | ||
60 | /* The result of the condition (true or false. */ | |
61 | tree value; | |
62 | }; | |
63 | ||
d3139801 JL |
64 | /* Structure for entries in the expression hash table. */ |
65 | ||
66 | typedef class expr_hash_elt * expr_hash_elt_t; | |
67 | ||
68 | class expr_hash_elt | |
69 | { | |
70 | public: | |
355fe088 | 71 | expr_hash_elt (gimple *, tree); |
d3139801 JL |
72 | expr_hash_elt (tree); |
73 | expr_hash_elt (struct hashable_expr *, tree); | |
74 | expr_hash_elt (class expr_hash_elt &); | |
75 | ~expr_hash_elt (); | |
76 | void print (FILE *); | |
77 | tree vop (void) { return m_vop; } | |
78 | tree lhs (void) { return m_lhs; } | |
79 | struct hashable_expr *expr (void) { return &m_expr; } | |
80 | expr_hash_elt *stamp (void) { return m_stamp; } | |
81 | hashval_t hash (void) { return m_hash; } | |
82 | ||
83 | private: | |
84 | /* The expression (rhs) we want to record. */ | |
85 | struct hashable_expr m_expr; | |
86 | ||
87 | /* The value (lhs) of this expression. */ | |
88 | tree m_lhs; | |
89 | ||
90 | /* The virtual operand associated with the nearest dominating stmt | |
91 | loading from or storing to expr. */ | |
92 | tree m_vop; | |
93 | ||
94 | /* The hash value for RHS. */ | |
95 | hashval_t m_hash; | |
96 | ||
97 | /* A unique stamp, typically the address of the hash | |
98 | element itself, used in removing entries from the table. */ | |
99b1c316 | 99 | class expr_hash_elt *m_stamp; |
d3139801 JL |
100 | |
101 | /* We should never be making assignments between objects in this class. | |
102 | Though it might allow us to exploit C++11 move semantics if we | |
103 | defined the move constructor and move assignment operator. */ | |
104 | expr_hash_elt& operator= (const expr_hash_elt&); | |
105 | }; | |
106 | ||
107 | /* Hashtable helpers. */ | |
108 | ||
109 | struct expr_elt_hasher : pointer_hash <expr_hash_elt> | |
110 | { | |
111 | static inline hashval_t hash (const value_type &p) | |
112 | { return p->hash (); } | |
113 | static bool equal (const value_type &, const compare_type &); | |
114 | static inline void remove (value_type &element) | |
115 | { delete element; } | |
116 | }; | |
117 | ||
118 | ||
119 | /* This class defines a unwindable expression equivalence table | |
120 | layered on top of the expression hash table. | |
121 | ||
122 | Essentially it's just a stack of available expression value pairs with | |
123 | a special marker (NULL, NULL) to indicate unwind points. */ | |
124 | ||
125 | class avail_exprs_stack | |
126 | { | |
127 | public: | |
128 | /* We need access to the AVAIL_EXPR hash table so that we can | |
129 | remove entries from the hash table when unwinding the stack. */ | |
130 | avail_exprs_stack (hash_table<expr_elt_hasher> *table) | |
131 | { m_stack.create (20); m_avail_exprs = table; } | |
132 | ~avail_exprs_stack (void) { m_stack.release (); } | |
133 | ||
134 | /* Push the unwinding marker onto the stack. */ | |
135 | void push_marker (void) { record_expr (NULL, NULL, 'M'); } | |
136 | ||
137 | /* Restore the AVAIL_EXPRs table to its state when the last marker | |
138 | was pushed. */ | |
1b2fe7d3 | 139 | void pop_to_marker (void); |
d3139801 JL |
140 | |
141 | /* Record a single available expression that can be unwound. */ | |
142 | void record_expr (expr_hash_elt_t, expr_hash_elt_t, char); | |
143 | ||
1b2fe7d3 JL |
144 | /* Get the underlying hash table. Would this be better as |
145 | class inheritance? */ | |
146 | hash_table<expr_elt_hasher> *avail_exprs (void) | |
147 | { return m_avail_exprs; } | |
148 | ||
a3d514f2 JL |
149 | /* Lookup and conditionally insert an expression into the table, |
150 | recording enough information to unwind as needed. */ | |
3d6fd7ce | 151 | tree lookup_avail_expr (gimple *, bool, bool, expr_hash_elt ** = NULL); |
a3d514f2 JL |
152 | |
153 | void record_cond (cond_equivalence *); | |
154 | ||
d3139801 JL |
155 | private: |
156 | vec<std::pair<expr_hash_elt_t, expr_hash_elt_t> > m_stack; | |
157 | hash_table<expr_elt_hasher> *m_avail_exprs; | |
158 | ||
0db8ddfc JL |
159 | /* For some assignments where the RHS is a binary operator, if we know |
160 | a equality relationship between the operands, we may be able to compute | |
161 | a result, even if we don't know the exact value of the operands. */ | |
162 | tree simplify_binary_operation (gimple *, class expr_hash_elt); | |
163 | ||
d3139801 JL |
164 | /* We do not allow copying this object or initializing one |
165 | from another. */ | |
166 | avail_exprs_stack& operator= (const avail_exprs_stack&); | |
167 | avail_exprs_stack (class avail_exprs_stack &); | |
168 | }; | |
169 | ||
f2a4ca15 JL |
170 | /* This class defines an unwindable const/copy equivalence table |
171 | layered on top of SSA_NAME_VALUE/set_ssa_name_value. | |
172 | ||
173 | Essentially it's just a stack of name,prev value pairs with a | |
174 | special marker (NULL) to indicate unwind points. */ | |
175 | ||
f6c72af4 JL |
176 | class const_and_copies |
177 | { | |
178 | public: | |
f2a4ca15 JL |
179 | const_and_copies (void) { m_stack.create (20); }; |
180 | ~const_and_copies (void) { m_stack.release (); } | |
a12cbc57 JL |
181 | |
182 | /* Push the unwinding marker onto the stack. */ | |
f2a4ca15 | 183 | void push_marker (void) { m_stack.safe_push (NULL_TREE); } |
a12cbc57 | 184 | |
465eeda4 | 185 | /* Restore the const/copies table to its state when the last marker |
a12cbc57 | 186 | was pushed. */ |
f6c72af4 | 187 | void pop_to_marker (void); |
a12cbc57 | 188 | |
0b604d2d JL |
189 | /* Record a single const/copy pair that can be unwound. This version |
190 | may follow the value chain for the RHS. */ | |
f6c72af4 | 191 | void record_const_or_copy (tree, tree); |
a12cbc57 JL |
192 | |
193 | /* Special entry point when we want to provide an explicit previous | |
0b604d2d JL |
194 | value for the first argument. Try to get rid of this in the future. |
195 | ||
196 | This version may also follow the value chain for the RHS. */ | |
f6c72af4 | 197 | void record_const_or_copy (tree, tree, tree); |
a12cbc57 | 198 | |
f6c72af4 | 199 | private: |
0db8ddfc JL |
200 | /* Record a single const/copy pair that can be unwound. This version |
201 | does not follow the value chain for the RHS. */ | |
202 | void record_const_or_copy_raw (tree, tree, tree); | |
203 | ||
f2a4ca15 | 204 | vec<tree> m_stack; |
d3139801 JL |
205 | const_and_copies& operator= (const const_and_copies&); |
206 | const_and_copies (class const_and_copies &); | |
f6c72af4 JL |
207 | }; |
208 | ||
d3139801 | 209 | void initialize_expr_from_cond (tree cond, struct hashable_expr *expr); |
a3d514f2 | 210 | void record_conditions (vec<cond_equivalence> *p, tree, tree); |
d3139801 | 211 | |
f6c72af4 | 212 | #endif /* GCC_TREE_SSA_SCOPED_TABLES_H */ |