Re: clang asm-goto support (Was Re: [PATCH v2] x86/retpoline: Add clang support)

[Linus Torvalds]

On Wed, Feb 14, 2018 at 7:31 AM, James Y Knight <jyknight@xxxxxxxxxx> wrote:
>
> IMO, inline asm is, generally, a valuable feature to provide in the
> compiler as an escape hatch, and asm goto is a relatively sane
> extension of it.

Side note: one thing that limits "asm goto" in gcc is the fact that
you can't have outputs.

If clang people are looking at "asm goto", the _syntax_ is actually
very straightforward, and there's really absolutely no point in trying
to make up some other interface.

But extending on what gcc does, and allowing outputs (possibly valid
in the fall-through case only, not in the cases where it jumps away to
a label) would be a big improvement on what gcc does.

At that point, we'd start to pester the gcc people to do the clang
thing, rather than the other way around. Because that's only fair ;)

                  Linus