3 * Copyright © 2010 Intel Corporation
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
25 #ifndef LOOP_ANALYSIS_H
26 #define LOOP_ANALYSIS_H
29 #include "util/hash_table.h"
32 * Analyze and classify all variables used in all loops in the instruction list
34 extern class loop_state
*
35 analyze_loop_variables(exec_list
*instructions
);
38 is_break(ir_instruction
*ir
)
40 return ir
!= NULL
&& ir
->ir_type
== ir_type_loop_jump
&&
41 ((ir_loop_jump
*) ir
)->is_break();
46 unroll_loops(exec_list
*instructions
, loop_state
*ls
,
47 const struct gl_shader_compiler_options
*options
);
51 * Tracking for all variables used in a loop
53 class loop_variable_state
: public exec_node
{
55 class loop_variable
*get(const ir_variable
*);
56 class loop_variable
*insert(ir_variable
*);
57 class loop_variable
*get_or_insert(ir_variable
*, bool in_assignee
);
58 class loop_terminator
*insert(ir_if
*, bool continue_from_then
);
62 * Variables that have not yet been classified
67 * Variables whose values are constant within the body of the loop
69 * This list contains \c loop_variable objects.
74 * Induction variables for this loop
76 * This list contains \c loop_variable objects.
78 exec_list induction_variables
;
81 * Simple if-statements that lead to the termination of the loop
83 * This list contains \c loop_terminator objects.
85 * \sa is_loop_terminator
87 exec_list terminators
;
90 * If any of the terminators in \c terminators leads to termination of the
91 * loop after a constant number of iterations, this is the terminator that
92 * leads to termination after the smallest number of iterations. Otherwise
95 loop_terminator
*limiting_terminator
;
98 * Hash table containing all variables accessed in this loop
100 hash_table
*var_hash
;
103 * Number of ir_loop_jump instructions that operate on this loop
105 unsigned num_loop_jumps
;
108 * Whether this loop contains any function calls.
112 loop_variable_state()
114 this->num_loop_jumps
= 0;
115 this->contains_calls
= false;
116 this->var_hash
= _mesa_pointer_hash_table_create(NULL
);
117 this->limiting_terminator
= NULL
;
120 ~loop_variable_state()
122 _mesa_hash_table_destroy(this->var_hash
, NULL
);
125 DECLARE_RALLOC_CXX_OPERATORS(loop_variable_state
)
129 class loop_variable
: public exec_node
{
131 /** The variable in question. */
134 /** Is the variable read in the loop before it is written? */
135 bool read_before_write
;
137 /** Are all variables in the RHS of the assignment loop constants? */
141 * Is there an assignment to the variable that is conditional, or inside a
144 bool conditional_or_nested_assignment
;
146 /** Reference to the first assignment to the variable in the loop body. */
147 ir_assignment
*first_assignment
;
149 /** Number of assignments to the variable in the loop body. */
150 unsigned num_assignments
;
153 * Increment value for a loop induction variable
155 * If this is a loop induction variable, the amount by which the variable
156 * is incremented on each iteration through the loop.
158 * If this is not a loop induction variable, NULL.
160 ir_rvalue
*increment
;
163 inline bool is_induction_var() const
165 /* Induction variables always have a non-null increment, and vice
168 return this->increment
!= NULL
;
172 inline bool is_loop_constant() const
174 const bool is_const
= (this->num_assignments
== 0)
175 || (((this->num_assignments
== 1)
176 && !this->conditional_or_nested_assignment
177 && !this->read_before_write
178 && this->rhs_clean
) || this->var
->data
.read_only
);
180 /* If the RHS of *the* assignment is clean, then there must be exactly
181 * one assignment of the variable.
183 assert((this->rhs_clean
&& (this->num_assignments
== 1))
184 || !this->rhs_clean
);
189 void record_reference(bool in_assignee
,
190 bool in_conditional_code_or_nested_loop
,
191 ir_assignment
*current_assignment
);
195 class loop_terminator
: public exec_node
{
198 : ir(NULL
), iterations(-1)
203 * Statement which terminates the loop.
208 * The number of iterations after which the terminator is known to
209 * terminate the loop (if that is a fixed value). Otherwise -1.
213 /* Does the if continue from the then branch or the else branch */
214 bool continue_from_then
;
223 * Get the loop variable state data for a particular loop
225 loop_variable_state
*get(const ir_loop
*);
227 loop_variable_state
*insert(ir_loop
*ir
);
235 * Hash table containing all loops that have been analyzed.
241 friend loop_state
*analyze_loop_variables(exec_list
*instructions
);
244 #endif /* LOOP_ANALYSIS_H */