> > I think one reason is that allowing zero_extracts of multi-word modes is > > (like this subreg thing) a little hard to pin down. What happens when > > WORDS_BIG_ENDIAN && !BYTES_BIG_ENDIAN > > Unless I had my grep wrong, the only such machines to do this are PDP11 > and ARM with special flags (-mbig-endian -mwords-little-endian) that > were "for backward compatibility with older versions of GCC" in 1999 [1]. > > So, is this special case worth keeping?
I'd argue yes, whether or not such machines exist because of orthogonality concerns: there's value in supporting all four possibilities.
