[Bug middle-end/85344] constants with the sign bit set causes sign extension which is unexpected but not documented in the user documentation

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85344

--- Comment #18 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Simple answer:
When the INTEGER_CST (unsigned short) is expanded into a const_int, the sign
extend happens due to the rules of const_int.