[PATCH] D34578: cmath: Support clang's -fdelayed-template-parsing

[Duncan P. N. Exon Smith via Phabricator via cfe-commits]

dexonsmith closed this revision.
dexonsmith added a comment.

In https://reviews.llvm.org/D34578#801519, @hfinkel wrote:

> In https://reviews.llvm.org/D34578#801357, @dexonsmith wrote:
>
> > Ping!  Hal, you committed r283051.  Do you have a problem with this?
>
>
> It looks like you're just renaming `__libcpp_isnan` and friends to __libcpp_isnan_or_builtin` and similar. LGTM


Thanks; committed in r307357.

>> (Incidentally, I noticed that r283051 was optimizing the implementation of <complex>. I wonder why we have so much code in that header, instead of calling out to libc's already-optimized <complex.h> implementation?)
> 
> This is definitely worth looking at (especially given that we don't support complex of user-defined types with those functions). Would making complex<double> use _Complex double, and so on, be an API break? Would that matter?

I think paragraph 4 of complex.numbers (from n4640) effectively enforces that `complex<T>` and `_Complex T` are ABI-compatible.


https://reviews.llvm.org/D34578