qbe

commit 1f4ff634187a9127ab160b2651c9decd80e82435
parent 4cee19ea9f989dc4b54bea3e657ec239929bf4d8
Author: Quentin Carbonneaux <quentin.carbonneaux@yale.edu>
Date:   Tue, 12 Apr 2016 14:40:11 -0400

subtle bug in liveness!

If on of the phis in a block A uses the result
of another one when coming from B, we have to
be careful!

Diffstat:
M
live.c
 | 
4
++--

1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/live.c b/live.c
@@ -7,13 +7,13 @@ liveon(BSet *v, Blk *b, Blk *s)
 	uint a;
 
 	bscopy(v, s->in);
-	for (p=s->phi; p; p=p->link) {
+	for (p=s->phi; p; p=p->link)
 		bsclr(v, p->to.val);
+	for (p=s->phi; p; p=p->link)
 		for (a=0; a<p->narg; a++)
 			if (p->blk[a] == b)
 			if (rtype(p->arg[a]) == RTmp)
 				bsset(v, p->arg[a].val);
-	}
 }
 
 static int