still optimize top-level expressions with loops and global decls

src/toplevel.c

@@ -330,7 +330,12 @@ static void expr_attributes(jl_value_t *v, int *has_intrinsics, int *has_defs)
  if (head == toplevel_sym || head == thunk_sym) {
  return;
  }
- else if (head == global_sym || head == const_sym || head == copyast_sym) {
+ else if (head == global_sym) {
+ // this could be considered has_defs, but loops that assign to globals
+ // might still need to be optimized.
+ return;
+ }
+ else if (head == const_sym || head == copyast_sym) {
  // Note: `copyast` is included here since it indicates the presence of
  // `quote` and probably `eval`.
  *has_defs = 1;