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
18 #include "iredges_t.h"
20 #define value_dominates(a, b) _value_dominates(a, b)
23 * Check dominance of two nodes in the same block.
24 * @param a The first node.
25 * @param b The second node.
26 * @return 1 if a comes before b in the same block or if a == b, 0 else.
28 static inline int _value_dominates_intrablock(const ir_node *a, const ir_node *b)
30 sched_timestep_t const as = sched_get_time_step(a);
31 sched_timestep_t const bs = sched_get_time_step(b);
36 * Check strict dominance of two nodes in the same block.
37 * @param a The first node.
38 * @param b The second node.
39 * @return 1 if a comes before b in the same block, 0 else.
41 static inline int _value_strictly_dominates_intrablock(const ir_node *a, const ir_node *b)
43 sched_timestep_t const as = sched_get_time_step(a);
44 sched_timestep_t const bs = sched_get_time_step(b);
49 * Check, if one value dominates the other.
50 * The dominance is not strict here.
51 * @param a The first node.
52 * @param b The second node.
53 * @return 1 if a dominates b or if a == b, 0 else.
55 static inline int _value_dominates(const ir_node *a, const ir_node *b)
57 const ir_node *block_a = get_block_const(a);
58 const ir_node *block_b = get_block_const(b);
61 * a and b are not in the same block,
62 * so dominance is determined by the dominance of the blocks.
64 if(block_a != block_b) {
65 return block_dominates(block_a, block_b);
69 * Dominance is determined by the time steps of the schedule.
71 return _value_dominates_intrablock(a, b);
75 * Check, if one value dominates the other.
76 * The dominance is strict here.
77 * @param a The first node.
78 * @param b The second node.
79 * @return 1 if a dominates b, 0 else.
81 static inline int _value_strictly_dominates(const ir_node *a, const ir_node *b)
83 const ir_node *block_a = get_block_const(a);
84 const ir_node *block_b = get_block_const(b);
87 * a and b are not in the same block,
88 * so dominance is determined by the dominance of the blocks.
90 if(block_a != block_b) {
91 return block_dominates(block_a, block_b);
95 * Dominance is determined by the time steps of the schedule.
97 return _value_strictly_dominates_intrablock(a, b);
101 * Check, if two values interfere.
102 * @param lv Liveness information
103 * @param a The first value.
104 * @param b The second value.
105 * @return 1, if a and b interfere, 0 if not.
107 static inline int be_values_interfere(const be_lv_t *lv, const ir_node *a, const ir_node *b)
109 int a2b = _value_dominates(a, b);
110 int b2a = _value_dominates(b, a);
114 * Adjust a and b so, that a dominates b if
115 * a dominates b or vice versa.
118 const ir_node *t = a;
124 /* If there is no dominance relation, they do not interfere. */
126 ir_node *bb = get_nodes_block(b);
129 * If a is live end in b's block it is
130 * live at b's definition (a dominates b)
132 if(be_is_live_end(lv, bb, a)) {
138 * Look at all usages of a.
139 * If there's one usage of a in the block of b, then
140 * we check, if this use is dominated by b, if that's true
141 * a and b interfere. Note that b must strictly dominate the user,
142 * since if b is the last user of in the block, b and a do not
144 * Uses of a not in b's block can be disobeyed, because the
145 * check for a being live at the end of b's block is already
148 foreach_out_edge(a, edge) {
149 const ir_node *user = get_edge_src_irn(edge);
150 if(get_nodes_block(user) == bb && !is_Phi(user) && _value_strictly_dominates(b, user)) {