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Re: [PATCH/gfortran] Fix rounding in constant folding

From: Tobias Schlüter <tobias dot schlueter at physik dot uni-muenchen dot de>
To: Steve Kargl <sgk at troutmask dot apl dot washington dot edu>
Cc: fortran at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
Date: Sat, 09 Apr 2005 20:57:59 +0200
Subject: Re: [PATCH/gfortran] Fix rounding in constant folding
References: <20050409162248.GA22593@troutmask.apl.washington.edu> <4258116E.9030303@physik.uni-muenchen.de> <20050409180327.GA64554@troutmask.apl.washington.edu>

Steve Kargl wrote:
>>In order of increasing probability: Does mpfr round incorrectly? Do we do
>>something wrong?  Or am I being stupid?

Further investigation proved the last of these options to be the case.

So I suggest you use "nearest (0.5, -1.)" for the small value, and something like
  scale (16., int (precision (1.) / log10 (2.))) + 1.
(this just gives Geert's number, but the criterion for creating it is "large
odd integral value with all floating point digits significant" for the larger
one.)

Sorry for the noise,
- Tobi

Follow-Ups:
- Re: [PATCH/gfortran] Fix rounding in constant folding
  - From: Tobias Schlüter

References:
- [PATCH/gfortran] Fix rounding in constant folding
  - From: Steve Kargl
- Re: [PATCH/gfortran] Fix rounding in constant folding
  - From: Tobias Schlüter
- Re: [PATCH/gfortran] Fix rounding in constant folding
  - From: Steve Kargl

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