Fix a couple terrible optimizer bugs

Just because an expression is always true or false, doesn't mean we can
execute it more often than it otherwise would be, unless it's also pure.
But that's equivalent to being identically -true/-false, so just check
that.

1 files changed, 2 insertions, 2 deletions

diff --git a/parse.c b/parse.c
index d4e945c..61c17a5 100644
--- a/parse.c
+++ b/parse.c
@@ -2568,7 +2568,7 @@ static struct expr *new_and_expr(const struct parser_state *state, struct expr *
 			debug_opt(state, "-O1: short-circuit: (%s %e %e) <==> %e\n", argv[0], lhs, rhs, lhs);
 			free_expr(rhs);
 			return lhs;
-		} else if (optlevel >= 2 && rhs->always_false && lhs->pure) {
+		} else if (optlevel >= 2 && lhs->pure && rhs == &expr_false) {
 			debug_opt(state, "-O2: purity: (%s %e %e) <==> %e\n", argv[0], lhs, rhs, rhs);
 			free_expr(lhs);
 			return rhs;
@@ -2664,7 +2664,7 @@ static struct expr *new_or_expr(const struct parser_state *state, struct expr *l
 		} else if (rhs == &expr_false) {
 			debug_opt(state, "-O1: disjunctive syllogism: (%s %e %e) <==> %e\n", argv[0], lhs, rhs, lhs);
 			return lhs;
-		} else if (optlevel >= 2 && rhs->always_true && lhs->pure) {
+		} else if (optlevel >= 2 && lhs->pure && rhs == &expr_true) {
 			debug_opt(state, "-O2: purity: (%s %e %e) <==> %e\n", argv[0], lhs, rhs, rhs);
 			free_expr(lhs);
 			return rhs;