[Bug demangler/92797] cplus_demangle() produces huge amount of output (on trunk)

[ibuclaw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92797

--- Comment #4 from ibuclaw at gcc dot gnu.org ---
At what point does the D demangler kick in?  It should only attempt to parse
symbols that begin with '_D'.