Wide characters and GCC

["Joseph S. Myers" <jsm28 at cam dot ac dot uk>]

Do we support target wchar_t wider than HOST_WIDE_INT in GCC?  There are
places this doesn't work - but is this something that we should in
principle support, or should be document it to be unsupported and then
give a compile time error if MAX_WCHAR_TYPE_SIZE > HOST_BITS_PER_WIDE_INT?
If we support wchar_t wider than HOST_WIDE_INT, do we support it wider
than HOST_WIDEST_INT?

We seem to support CHAR_TYPE_SIZE different from BITS_PER_UNIT - which at
the C level would mean that the C byte with sizeof returning 1 is not the
same as the natural hardware byte.  No machine description actually seems
to use this feature.  To what extent is this a genuinely supported useful
feature?

What should the formats of both narrow and wide STRING_CSTs be when the
target byte size (either hardware or C-level) is not the same as the host
byte size?  The only vaguely active ports for which this is the case are I
think the C4X and PDP-10 ports; I've CC:ed their maintainers.  What
testcases from the GCC testsuite fail on such targets because of problems
with GCC's support for different sizes of char?

-- 
Joseph S. Myers
jsm28@cam.ac.uk