r225244 - Sema: analyze I,J,K,M,N,O constraints

[Joerg Sonnenberger]

On Thu, Jan 15, 2015 at 10:41:51AM -0800, Chandler Carruth wrote:
> On Thu, Jan 15, 2015 at 10:29 AM, Joerg Sonnenberger <
> joerg at britannica.bec.de> wrote:
> 
> > See the inb example. All fixes are pessimations for the code. People
> > complained enough about the (in)ability of __builtin_constant_p to get
> > it delayed to the backend, this is IMO just the same.
> >
> 
> I agree it is the same, however I have heard extremely little complaining
> about __builtin_constant_p. I've also not heard any complaints other than
> yours about this change -- most of the complaints I've heard have been
> about the terribly brittle code it uncovered and is now getting fixed.

Given that I am often the first person to see breakage in random
software, I'm not too surprised. So the real question would be -- why is
this not just a warning? I don't think anyone (including me) would
object to that, but it would make it possible to still use the feature
when necessary / useful.

Joerg