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Re: [PATCHv2 06/14] Replace M_PI2l with pi_2_d in libm-test.inc


On Fri, 20 May 2016, Paul E. Murphy wrote:

> This is useful in situations where the long double type is
> less precise than the type under test.
> 
> 	* libm-test.inc: Replace usage of M_PI2l with
> 	[pi_2_d]: New macro.

I'm not convinced that adding several extra local constants is the right 
approach here.

For the API for float128 to be feature-complete compared to long double, 
it should include constants such as M_PI_2f128 for all the long double 
constants in <math.h>.  Which means that there is always a constant from 
<math.h> that can be used in these cases; you don't need yet another copy 
of the digits of this constant.  You might, for example, have a macro MCST 
defined for each type and use MCST (PI_2) here (which would expand to 
M_PI_2 for float and double - there aren't float versions of these 
<math.h> constants - M_PI_2l for long double, M_PI_2f128 for float128).

-- 
Joseph S. Myers
joseph@codesourcery.com


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