From 69009071293d63bc39d93ce2d96ba51df2fcaa70 Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Thu, 3 May 2012 19:32:44 +0900
Subject: [PATCH] Remove dead labels when jump threading.
This lets the dead block removal do a better job.
---
tools/qfcc/source/statements.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/tools/qfcc/source/statements.c b/tools/qfcc/source/statements.c
index 323925605..f2f0ccc4b 100644
--- a/tools/qfcc/source/statements.c
+++ b/tools/qfcc/source/statements.c
@@ -1026,6 +1026,7 @@ remove_label_from_dest (ex_label_t *label)
if (!label)
return;
+ debug (0, "dropping deceased label %s", label->name);
sblock = label->dest;
for (l = &sblock->labels; *l; l = &(*l)->next) {
if (*l == label) {
@@ -1040,29 +1041,30 @@ static void
thread_jumps (sblock_t *blocks)
{
sblock_t *sblock;
- ex_label_t *label, *l;
- statement_t *s;
if (!blocks)
return;
for (sblock = blocks; sblock->next; sblock = sblock->next) {
+ statement_t *s;
+ ex_label_t **label, *l;
+
s = (statement_t *) sblock->tail;
if (!strcmp (s->opcode, "<GOTO>"))
- label = s->opa->o.label;
+ label = &s->opa->o.label;
else if (!strncmp (s->opcode, "<IF", 3))
- label = s->opb->o.label;
+ label = &s->opb->o.label;
else
continue;
- for (l = label;
+ for (l = *label;
(l->dest->statements
&& !strcmp (l->dest->statements->opcode, "<GOTO>"));
l = l->dest->statements->opa->o.label) {
}
- if (l != label) {
- if (!strcmp (s->opcode, "<GOTO>"))
- s->opa->o.label = l;
- else if (!strncmp (s->opcode, "<IF", 3))
- s->opb->o.label = l;
+ if (l != *label) {
+ if (!--(*label)->used)
+ remove_label_from_dest (*label);
+ l->used++;
+ *label = l;
}
}
}