fix bug of lhs getting culled if same node optimized out of rhs

1 files changed, 33 insertions, 28 deletions

diff --git a/main.c b/main.c
index ce8981b..8533e49 100644
--- a/main.c
+++ b/main.c
@@ -213,41 +213,46 @@ Node *parse_term(Lexer *l, Proc *p) {
 	return node_peephole(node, p, l);
 }
 
+NodeType tok_to_bin_op(Token t) {
+	switch (t) {
+	case TOK_PLUS: return N_OP_ADD; break;
+	case TOK_MINUS: return N_OP_SUB; break;
+	case TOK_ASTERISK: return N_OP_MUL; break;
+	case TOK_SLASH: return N_OP_DIV; break;
+	case TOK_NOT: return N_OP_NOT; break;
+	case TOK_AND: return N_OP_AND; break;
+	case TOK_OR: return N_OP_OR; break;
+	case TOK_XOR: return N_OP_XOR; break;
+	case TOK_SHL: return N_OP_SHL; break;
+	case TOK_SHR: return N_OP_SHR; break;
+	case TOK_EQL: return N_CMP_EQL; break;
+	case TOK_NEQ: return N_CMP_NEQ; break;
+	case TOK_LES: return N_CMP_LES; break;
+	case TOK_GTR: return N_CMP_GTR; break;
+	case TOK_LTE: return N_CMP_LTE; break;
+	case TOK_GTE: return N_CMP_GTE; break;
+	default: return N_START; break;
+	}
+}
+
 /* TODO: operator precedence would be kinda nice actually, sad to say */
 Node *parse_expr(Lexer *l, Proc *p) {
 	LexSpan pos = l->pos;
 	Node *lhs = parse_term(l, p);
-	if (TMASK(l->tok) & (TM_PLUS | TM_MINUS | TM_ASTERISK | TM_SLASH
-		| TM_NOT | TM_AND | TM_XOR | TM_OR | TM_SHL | TM_SHR
-		| TM_EQL | TM_NEQ | TM_LES | TM_GTR | TM_LTE | TM_GTE)) {
-		Token t = l->tok;
+	NodeType nt = tok_to_bin_op(l->tok);;
+	assert(lhs->refs > 0);
+	if (nt != N_START) {
 		lex_next(l);
+		/* necessary because if lhs is a deduplicated literal, it may be an input to rhs
+		 * and therefore culled by peephole optimizations */
+		node_add(p, lhs, p->keepalive);
 		Node *rhs = parse_expr(l, p);
-		NodeType nt = N_OP_ADD;
-		switch (t) {
-		case TOK_PLUS: nt = N_OP_ADD; break;
-		case TOK_MINUS: nt = N_OP_SUB; break;
-		case TOK_ASTERISK: nt = N_OP_MUL; break;
-		case TOK_SLASH: nt = N_OP_DIV; break;
-		case TOK_NOT: nt = N_OP_NOT; break;
-		case TOK_AND: nt = N_OP_AND; break;
-		case TOK_OR: nt = N_OP_OR; break;
-		case TOK_XOR: nt = N_OP_XOR; break;
-		case TOK_SHL: nt = N_OP_SHL; break;
-		case TOK_SHR: nt = N_OP_SHR; break;
-		case TOK_EQL: nt = N_CMP_EQL; break;
-		case TOK_NEQ: nt = N_CMP_NEQ; break;
-		case TOK_LES: nt = N_CMP_LES; break;
-		case TOK_GTR: nt = N_CMP_GTR; break;
-		case TOK_LTE: nt = N_CMP_LTE; break;
-		case TOK_GTE: nt = N_CMP_GTE; break;
-		default: break;
-		}
-		lhs = node_new(p, nt, lhs, rhs);
+		Node *n = node_peephole(node_new(p, nt, lhs, rhs), p, l);
+		node_remove(p, lhs, p->keepalive);
+		lhs = n;
 	}
-	Node *n = node_peephole(lhs, p, l);
-	n->src_pos = (LexSpan) { pos.ofs, l->pos.ofs - pos.ofs };
-	return n;
+	lhs->src_pos = (LexSpan) { pos.ofs, l->pos.ofs - pos.ofs };
+	return lhs;
 }
 
 void parse_toplevel(Lexer *l, Unit *u) {