On Fri, 30 Nov 2018, Richard Biener wrote: > > Ping - as I think this approach addresses the root of the problem, I > > wouldn't > > like it to be forgotten. > > I agree this is also useful but it addresses another issue (that may appear to > be related). asm inline is really a hint to the inliner estimates (with no > way > to get semantics botched) while marking off-section parts is making the > asm text more precise also affecting code generation and thus has the > possibility to cause correctness issues (if you say mark everything as > off-section just to make it inline better).
I don't think that's true: if the user marks too much of the template as off-section and makes GCC under-estimate branch ranges, they may receive an error from the assembler. But that's a build failure, not a correctness issue. Surely build error is a reasonable outcome from misuse of inline asm. > I'm sympathtetic to both patches but clearly the kernel folks have shown > need for the inline hint (arguably the kernel folks are the ones we could > expect to get usages of %` correct ...). I haven't seen any comments > from possible users of %` FWIW, when I raised the idea in the kernel thread, the response from Borislav was: >> I don't mind it but I see you guys are still discussing what would be >> the better solution here, on the gcc ML. And we, as one user, are a >> happy camper as long as it does what it is meant to do. But how the >> feature looks like syntactically is something for gcc folk to decide as >> they're going to support it for the foreseeable future and I'm very well >> aware of how important it is for a supportable feature to be designed >> properly. Alexander
