https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89482
--- Comment #9 from David <gccbugzilla at limegreensocks dot com> --- (In reply to Ciro Santilli from comment #8) - I haven't posted a patch file since I wasn't sure that I was all that close to being done. But I'm certainly not opposed to the idea. Were you volunteering to move this forward? - "document the aarch32 modifiers" It's been discussed, but since I'm already unable to move aarch64 forward... - As I've mentioned, I'm not enough of an ARM expert to explain why things are they way they are. It's possible that the reason there are "both 't' and 'w'" has to do with history. Additionally, remember that machine constraints aren't just for inline asm. They are used in the MD files as well where the differences may have more meaning.
