From: Mikael Morin <morin-mikael@orange.fr>
To: FX <fxcoudert@gmail.com>
Cc: Fortran <fortran@gcc.gnu.org>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Fortran 2018 rounding modes changes
Date: Mon, 19 Sep 2022 19:09:46 +0200 [thread overview]
Message-ID: <c6cd7bee-01c1-afee-6520-ae67189f0487@orange.fr> (raw)
In-Reply-To: <52A7FAB8-735E-42D8-97A6-7E4C4F108C5E@gmail.com>
Le 19/09/2022 à 18:17, FX a écrit :
> Hi,
>
>>> 2. Add the optional RADIX argument to IEEE_SET_ROUNDING_MODE and IEEE_GET_ROUNDING_MODE. It is unused for now, because we do not support floating-point radices other than 2.
>> If we accept the argument, we have to support it somehow.
>> So for IEEE_GET_ROUNDING_MODE (*, 10), we should return IEEE_OTHER, shouldn't we?
>
> I think I disagree. We do not support any real kind with radix 10, so calling IEEE_GET_ROUNDING_MODE with RADIX=10 is invalid. Or, in another interpretation, the rounding mode is whatever-you-want-to-call it, since you cannot perform arithmetic in that radix anyway.
>
Hmm, not really convinced, but that's a possible interpretation, I guess.
>
>> There is no problem for IEEE_SET_ROUNDING_MODE (*, 10) as there is no way this to be a valid call if radix 10 is not supported, but changing a compile time error to a runtime unexpected behavior seems like a step backwards.
>
> What do you mean by that? The behavior is not unexpected, the value returned by IEEE_GET_ROUNDING_MODE for RADIX=10 is irrelevant and cannot be used for anything useful.
>
My sentence was about IEEE_*S*ET_ROUNDING_MODE actually.
My point that we previously reported an error (at compile time) to a
user that would try to pass a radix 10 while we now silently do...
something else that was requested (i.e. set the radix 2 rounding mode).
I think it's worth at least documenting that only radix 2 is supported.
next prev parent reply other threads:[~2022-09-19 17:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 18:29 FX
2022-08-31 20:42 ` Bernhard Reutner-Fischer
2022-08-31 21:23 ` FX
2022-09-10 10:21 ` FX
2022-09-19 12:26 ` FX
2022-09-19 15:35 ` Mikael Morin
2022-09-19 16:17 ` FX
2022-09-19 17:09 ` Mikael Morin [this message]
2022-09-19 17:29 ` FX
2022-09-21 9:15 ` FX
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