r230255 - Only lower __builtin_setjmp / __builtin_longjmp to

[Joerg Sonnenberger]

On Tue, Mar 10, 2015 at 05:44:00PM -0700, John McCall wrote:
> I'm sorry, I missed your early request, and your response to my review.
> I'm much more likely to respond quickly if you keep me as a recipient.
> 
> I really would like you to diagnose this in Sema, please.  Target-specific
> restrictions are not new, especially on builtin functions.  But if you do
> that, it's approved for merge.

But Sema is too early, it breaks valid use cases that are never going to
hit the backend at all. Consider clang --analyze or clang-modernize.
Especially the latter is completely target independent, so it shouldn't
get fail on code that is valid on one platform and only fails on another
because of LLVM bugs.

Joerg