[PATCH] D31561: cmath: Skip Libc for integral types in isinf, etc.

[Eric Fiselier via Phabricator via cfe-commits]

EricWF accepted this revision.
EricWF added a comment.
This revision is now accepted and ready to land.

LGTM minus inline comments.



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Comment at: libcxx/include/math.h:354
 inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
 signbit(_A1 __lcpp_x) _NOEXCEPT
----------------
hfinkel wrote:
> I think that it would be safer / easier to understand if we used !std::is_integral here. It is true for all standard types that std::is_arithmetic implies is_integral or is_floating_point, but it seems likely that some implementations have arithemtic types that are neither (e.g. fixed-point types), and user-defined types seem likely.
@dexonsmith Could you please codify this point in a comment above the function. My initial reaction was "Why aren't we using `std::is_floating_point` instead". 


https://reviews.llvm.org/D31561