r231245 - Adjust the changes from r230255 to bail out if the backend can't lower

[Joerg Sonnenberger]

On Wed, Mar 04, 2015 at 02:33:48PM -0800, John McCall wrote:
> > On Mar 4, 2015, at 6:25 AM, Joerg Sonnenberger <joerg at bec.de> wrote:
> > Author: joerg
> > Date: Wed Mar  4 08:25:35 2015
> > New Revision: 231245
> > 
> > URL: http://llvm.org/viewvc/llvm-project?rev=231245&view=rev
> > Log:
> > Adjust the changes from r230255 to bail out if the backend can't lower
> > __builtin_setjmp/__builtin_longjmp and don't fall back to the libc
> > functions.
> 
> Thank you.  I think it would be reasonable for the AST-level TargetInfo
> to answer this question and then diagnose it in Sema.  We generally
> prefer Sema diagnostics over IRGen diagnostics, all else being equal.

Well, strictly speaking, I think IRGen is more correct here.
Semantically, the code is correct, it is a limitation of the target that
restricts it.

Joerg