[Bug fortran/91310] Read overflow generated by character array assignment to self

[foreese at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91310

--- Comment #1 from Fritz Reese <foreese at gcc dot gnu.org> ---
Created attachment 46648
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46648&action=edit
test case 1