Message-ID: <4592D71E.8070401@yahoo.com>
Date: Wed, 27 Dec 2006 14:27:10 -0600
From: Roman Kononov <kononov195-pgsql@yahoo.com>
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To: pgsql-hackers@postgresql.org
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Bruce Momjian <bruce@momjian.us>,
	PostgreSQL-patches <pgsql-patches@postgresql.org>
Subject: Re: [PATCHES] [BUGS] BUG #2846: inconsistent and confusing handling
References: <200612271844.kBRIiVb18465@momjian.us>
	<19208.1167246902@sss.pgh.pa.us>
In-Reply-To: <19208.1167246902@sss.pgh.pa.us>
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On 12/27/2006 01:15 PM, Tom Lane wrote:
> I'm not convinced that you're fixing things so much as doing your best
> to destroy IEEE-compliant float arithmetic behavior.
> 
> I think what we should probably consider is removing CheckFloat4Val
> and CheckFloat8Val altogether, and just letting the float arithmetic
> have its head.  Most modern hardware gets float arithmetic right per
> spec, and we shouldn't be second-guessing it.

I vote for complete IEEE-compliance. No exceptions with pure floating
point math. Float -> int conversions should reject overflow, INF and
NaN. Float -> numeric conversions should reject INF.

> A slightly less radical proposal is to reject only the case where
> isinf(result) and neither input isinf(); and perhaps likewise with
> respect to NaNs.

This might look like another possibility for confusion. For example
INF-INF=NaN.

Regards,
Roman.