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authorSebastian Hack <hack@ipd.info.uni-karlsruhe.de>2005-07-27 14:51:51 +0200
committerSebastian Hack <hack@ipd.info.uni-karlsruhe.de>2005-07-27 14:51:51 +0200
commit88ad2af117564fcfda8b052a0bef41241fdcac1a (patch)
treed45fe12b926de1a824ed77274caab6b1e9881630 /ir/be/bera.c
parent9d439a4d682b1c9a697b2fabfffe62d43998da3f (diff)
Re-implemented values_interfere
Diffstat (limited to 'ir/be/bera.c')
-rw-r--r--ir/be/bera.c68
1 files changed, 34 insertions, 34 deletions
diff --git a/ir/be/bera.c b/ir/be/bera.c
index cb234bc..7055ec6 100644
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -54,46 +54,46 @@ int values_interfere(const ir_node *a, const ir_node *b)
int a2b = value_dominates(a, b);
int b2a = value_dominates(b, a);
- /*
- * Adjust a and b so, that a dominates b if
- * a dominates b or vice versa.
- */
- if(b2a) {
- const ir_node *t = a;
- a = b;
- b = t;
- }
-
- /*
- * If either a dmoninates b or vice versa
- * check if there is usage which is dominated by b.
- *
- * remind, that if a and b are in a dom relation, a always dominates b
- * here due to the if above.
- */
- if(a2b + b2a) {
+ /* If there is no dominance relation, they do not interfere. */
+ if(a2b + b2a > 0) {
const ir_edge_t *edge;
+ ir_node *ba = get_nodes_block(a);
+ ir_node *bb = get_nodes_block(b);
- /* Look at all usages of a */
- foreach_out_edge(a, edge) {
- const ir_node *user = edge->src;
+ /*
+ * Adjust a and b so, that a dominates b if
+ * a dominates b or vice versa.
+ */
+ if(b2a) {
+ const ir_node *t = a;
+ a = b;
+ b = t;
+ }
- /*
- * If the user is a phi we must check the last instruction in the
- * corresponding phi predecessor block since the phi is not a
- * proper user.
- */
- if(is_Phi(user)) {
- ir_node *phi_block = get_nodes_block(user);
- user = sched_last(get_Block_cfgpred_block(phi_block, edge->pos));
- }
+ /*
+ * If a is live end in b's block it is
+ * live at b's definition (a dominates b)
+ */
+ if(is_live_end(bb, a))
+ return 1;
- /* If b dominates a user of a, we can safely return 1 here. */
- if(value_dominates(b, user)) {
- return 1;
+ /*
+ * Look at all usages of a.
+ * If there's one usage of a in the block of b, then
+ * we check, if this use is dominated by b, if that's true
+ * a and b interfere.
+ * Uses of a not in b's block can be disobeyed, because the
+ * check for a being live at the end of b's block is already
+ * performed.
+ */
+ foreach_out_edge(a, edge) {
+ const ir_node *user = edge->src;
+ if(get_nodes_block(user) == bb
+ && !is_Phi(user)
+ && value_dominates(b, user))
+ return 1;
}
}
-
}
return 0;