3 files changed, 12 insertions, 25 deletions

diff --git a/ir.c b/ir.c
index c935a67..42691ee 100644
--- a/ir.c
+++ b/ir.c
@@ -99,29 +99,18 @@ int type_check(Node *n) {
 /* nodes */
 
 const char *node_type_name(NodeType t) {
-	const char *names[] = {
-		"N/A",
-		"start", "if-else", "region", "phi", "stop",
-		"projection",
-		"return",
-		"keepalive",
-		"literal",
-		"add", "sub", "mul", "div",
-		"and", "or", "xor",
-		"lshift", "rshift",
-		"neg", "not",
-		"equal",
-		"not-equal",
-		"less",
-		"greater",
-		"less-or-equal",
-		"greater-or-equal",
+	static const char *names[] = {
+#define X(n, s) s,
+		NODE_TYPE_LIST
+#undef X
 	};
 	return names[t];
 }
 
 void node_die(Node *n, Proc *p) {
 	assert(n->refs == 0);
+	assert(n->op != N_DEAD);
+	n->op = N_DEAD;
 	n->prev_free = p->free_list;
 	p->free_list = n;
 }
@@ -182,6 +171,8 @@ void node_set_in(Proc *p, Node *n, int idx, Node *to) {
 }
 
 void node_add(Proc *p, Node *src, Node *dest) {
+	if (src) assert(src->op != N_DEAD);
+	if (dest) assert(dest->op != N_DEAD);
 	node_add_in(p, dest, src);
 	if (!src) return;
 	node_add_out(p, src, dest);
@@ -194,9 +185,11 @@ void node_add(Proc *p, Node *src, Node *dest) {
 }
 
 void node_remove(Proc *p, Node *src, Node *dest) {
+	assert(dest->op != N_DEAD);
 	node_del_in(dest, src);
 	if (dest->refs < 1) node_die(dest, p);
 	if (src) {
+		assert(src->op != N_DEAD);
 		node_del_out(src, dest);
 		if (src->out.len < 1) node_kill(src, p);
 	}
@@ -208,6 +201,7 @@ Node *node_new_empty(Proc *p, NodeType t) {
 	Node *n;
 	if (p->free_list) {
 		n = p->free_list;
+		assert(n->op == N_DEAD);
 		p->free_list = n->prev_free;
 		memset(n, 0, sizeof(Node));
 	} else {
diff --git a/ir.h b/ir.h
index adb1039..9c6fc0b 100644
--- a/ir.h
+++ b/ir.h
@@ -51,6 +51,7 @@ void type_err(struct Node *n, Lexer *l);
 
 #define NODE_TYPE_LIST\
 	X(NONE, "invalid node")\
+	X(DEAD, "dead node")\
 	X(START, "start")\
 	X(IF_ELSE, "if-else")\
 	X(REGION, "region")\
diff --git a/test.lang b/test.lang
index 5535a4e..24a931d 100644
--- a/test.lang
+++ b/test.lang
@@ -3,14 +3,6 @@ func main(a, b i64) i64 {
 		let t = a
 		a := b
 		b := t
-	} else {
-		a := 5
-		b := 10
-		if a = b {
-			let t = a
-			a := b
-			b := t
-		}
 	}
 	return a + b
 }