[Bug c++/60955] Erroneous warning about taking address of register with std=c++1y

[matt at godbolt dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60955

--- Comment #1 from Matt Godbolt <matt at godbolt dot org> ---
The previous snippet wasn't quite as minimal as it could be.  This single line
also reproduces it:

unsigned int erroneous_warning(register int a) { return (a); }

Jonathan Wakely mentioned this may be related to this bug:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57573