https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126237
--- Comment #2 from Stephen Kell <srk31 at srcf dot ucam.org> --- Indeed, as mentioned, the "D" is fine in this case but not for other registers that may lack a specific constraint. And yes, true that the docs mention *something*. My point is that it's not commensurately clear and explicit, relative to the (considerable) strangeness of the behaviour... e.g. consider how using "D" without dropping the asm from the local also yields broken code. I'll take a look at Hard Register Constraints... thanks for the pointer.
