huge error for pow

[Paul Zimmermann]

       Hi Jeff,

this would not make sense on our side, since in CORE-MATH we are currently
completing a correctly rounded pow function, which will be available in a
few weeks, and can then be integrated into newlib.

Best regards,
Paul

> From: Jeff Johnston <jjohnstn@redhat.com>
> Date: Tue, 7 Feb 2023 16:48:14 -0500
> Cc: newlib@sourceware.org, vincenzo.innocente@cern.ch
> 
> 
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> 
> Thanks Paul,
> 
> Do you think you can put together a patch?
> 
> -- Jeff J.
> 
> On Tue, Feb 7, 2023 at 9:27 AM Paul Zimmermann <Paul.Zimmermann@inria.fr>
> wrote:
> 
>         Hi,
> 
>  while testing Newlib 4.3.0, I noticed the following huge error:
> 
>  zimmerma@salade:~/svn/tbd/20/src/binary64$ VERBOSE=-v ./doitb.newlib pow
>  1000
>  Checking pow with newlib-4.3.0.20230120
>  Using seed 1619945
>  pow 0 -1 -0x1.647ff80007ff8p-576,-0x1.3d018267f12fp+48 [inf] inf inf
>  libm gives inf
>  mpfr gives -inf
> 
>  The exponent y in x^y is a large odd integer, thus since x is negative
>  we
>  should get a negative number as result.
> 
>  This issue was apparently already present in 3.3.0, but we only
>  discovered
>  it now.
> 
>  Best regards,
>  Paul