[Bug target/56875] vax target miscompiles short negative constants for 64bit values

[jbglaw@lug-owl.de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56875

--- Comment #5 from Jan-Benedict Glaw <jbglaw@lug-owl.de> ---
Created attachment 30872
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30872&action=edit
Updated patch including testcase.