https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68281
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Josh Stone from comment #2) > This may also be significant: > > bool > base_query::get_number_param(literal_map_t const & params, > interned_string k, long & v) > { > int64_t value; > bool present = derived_probe_builder::get_param (params, k, value); > v = (long) value; This is an lvalue-to-rvalue conversion, which is undefined if value is uninitialized, so the compiler can assume that value must always be initialized by the call to get_param. If this function body is visible when line 1002 is compiled the compiler can assume that callees_num_val always gets set to a correctly initialized value, so it's safe to re-order the conditions later.