RFC: removing slow paths in various dbl-64 libm functions

[Siddhesh Poyarekar]

On Thu, Nov 26, 2015 at 06:09:08PM +0000, Joseph Myers wrote:
> We now have documented libm accuracy goals which do not involve these 
> functions being correctly rounded (and indeed on some architectures other 
> implementations are used that are not correctly rounded).  We also have TS 
> 18661-4 defining names such as crsin that are reserved for 
> correctly-rounded (for all rounding modes) versions of those functions.

We could even go the whole way and define crsin, crcos, etc. symbols
with the current implementation and drop the mp path completely for
the sin, cos, etc. functions regardless of how inaccurate the fast
phase computation results are.

Siddhesh