[Bug middle-end/68336] False positive Wreturn-type warning

[yyc1992 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68336

--- Comment #1 from Yichao Yu <yyc1992 at gmail dot com> ---
Ref clang bug report https://llvm.org/bugs/show_bug.cgi?id=25521