4 * @author Sebastian Hack
6 * Principal routines for liveness and interference checks.
8 * Copyright (C) 2007 Universitaet Karlsruhe
9 * Released under the GPL
12 #ifndef _BELIVECHK_T_H
13 #define _BELIVECHK_T_H
17 #include "iredges_t.h"
20 * Check dominance of two nodes in the same block.
21 * @param a The first node.
22 * @param b The second node.
23 * @return 1 if a comes before b in the same block or if a == b, 0 else.
25 static inline int _value_dominates_intrablock(const ir_node *a, const ir_node *b)
27 assert(sched_is_scheduled(a));
28 assert(sched_is_scheduled(b));
29 sched_timestep_t const as = sched_get_time_step(a);
30 sched_timestep_t const bs = sched_get_time_step(b);
35 * Check strict dominance of two nodes in the same block.
36 * @param a The first node.
37 * @param b The second node.
38 * @return 1 if a comes before b in the same block, 0 else.
40 static inline int _value_strictly_dominates_intrablock(const ir_node *a, const ir_node *b)
42 assert(sched_is_scheduled(a));
43 assert(sched_is_scheduled(b));
44 sched_timestep_t const as = sched_get_time_step(a);
45 sched_timestep_t const bs = sched_get_time_step(b);
50 * Check, if one value dominates the other.
51 * The dominance is not strict here.
52 * @param a The first node.
53 * @param b The second node.
54 * @return 1 if a dominates b or if a == b, 0 else.
56 static inline int _value_dominates(const ir_node *a, const ir_node *b)
58 const ir_node *block_a = get_block_const(a);
59 const ir_node *block_b = get_block_const(b);
62 * a and b are not in the same block,
63 * so dominance is determined by the dominance of the blocks.
65 if(block_a != block_b) {
66 return block_dominates(block_a, block_b);
70 * Dominance is determined by the time steps of the schedule.
72 return _value_dominates_intrablock(a, b);
76 * Check, if one value dominates the other.
77 * The dominance is strict here.
78 * @param a The first node.
79 * @param b The second node.
80 * @return 1 if a dominates b, 0 else.
82 static inline int _value_strictly_dominates(const ir_node *a, const ir_node *b)
84 const ir_node *block_a = get_block_const(a);
85 const ir_node *block_b = get_block_const(b);
88 * a and b are not in the same block,
89 * so dominance is determined by the dominance of the blocks.
91 if(block_a != block_b) {
92 return block_dominates(block_a, block_b);
96 * Dominance is determined by the time steps of the schedule.
98 return _value_strictly_dominates_intrablock(a, b);
102 * Check, if two values interfere.
103 * @param lv Liveness information
104 * @param a The first value.
105 * @param b The second value.
106 * @return 1, if a and b interfere, 0 if not.
108 static inline int be_values_interfere(const be_lv_t *lv, const ir_node *a, const ir_node *b)
110 int a2b = _value_dominates(a, b);
111 int b2a = _value_dominates(b, a);
115 * Adjust a and b so, that a dominates b if
116 * a dominates b or vice versa.
119 const ir_node *t = a;
125 /* If there is no dominance relation, they do not interfere. */
127 ir_node *bb = get_nodes_block(b);
130 * If a is live end in b's block it is
131 * live at b's definition (a dominates b)
133 if(be_is_live_end(lv, bb, a)) {
139 * Look at all usages of a.
140 * If there's one usage of a in the block of b, then
141 * we check, if this use is dominated by b, if that's true
142 * a and b interfere. Note that b must strictly dominate the user,
143 * since if b is the last user of in the block, b and a do not
145 * Uses of a not in b's block can be disobeyed, because the
146 * check for a being live at the end of b's block is already
149 foreach_out_edge(a, edge) {
150 const ir_node *user = get_edge_src_irn(edge);
151 if(get_nodes_block(user) == bb && !is_Phi(user) && _value_strictly_dominates(b, user)) {
162 #define value_dominates(a, b) _value_dominates(a, b)