scc

commit 774054fa8b77986acb2fa39f0bfe2a8c642b32c5
parent 676d846b1588b139ee9192f9e5d5a90f74fa5ec5
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sat, 10 Feb 2024 22:54:28 +0100

as: Fold labels with known values

When a label has a constant value then it can be fold like
any other number.

Diffstat:
M
src/cmd/as/expr.c
 | 
21
+++++++++++++++++----

1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/src/cmd/as/expr.c b/src/cmd/as/expr.c
@@ -36,12 +36,25 @@ deltree(Node *np)
 	delete(arena, np);
 }
 
+static int
+constant(Node *np)
+{
+	if (np->op == NUMBER)
+		return 1;
+	if (np->op == IDEN && np->sym->flags & FDEF)
+		return 1;
+	return 0;
+}
+
 static Node *
 fold(int op, Node *l, Node *r)
 {
 	Node *np;
 	TUINT val, lv, rv;
 
+	if (!constant(l) || !constant(r))
+		return NULL;
+
 	lv = l->sym->value;
 	rv = r->sym->value;
 
@@ -115,10 +128,10 @@ binary(int op, Node *l, Node *r)
 	int addr;
 	Node *np;
 
-	if (l->op == NUMBER && r->op == NUMBER)
-		return fold(op, l, r);
-	else
-		abort();
+	if ((np = fold(op, l, r)) != NULL)
+		return np;
+	abort();
+
 	np = node(op, l, r);
 	np->addr = addr;