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Date: Tue, 30 Aug 2022 22:32:54 +0000
From: Joseph Myers <joseph@codesourcery.com>
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To: Jakub Jelinek <jakub@redhat.com>
CC: Aldy Hernandez <aldyh@redhat.com>, GCC patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Add support for floating point endpoints to frange.
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On Mon, 29 Aug 2022, Jakub Jelinek via Gcc-patches wrote:

> On Mon, Aug 29, 2022 at 03:45:33PM +0200, Aldy Hernandez wrote:
> > For convenience, singleton_p() returns false for a NAN.  IMO, it makes
> > the implementation cleaner, but I'm not wed to the idea if someone
> > objects.
> 
> If singleton_p() is used to decide whether one can just replace a variable
> with singleton range with a constant, then certainly.
> If MODE_HAS_SIGNED_ZEROS, zero has 2 representations (-0.0 and 0.0) and

Note also for decimal floating point that many real numbers - if they 
don't require the full precision of the type to represent the number - can 
be represented with different quantum exponents (so compare equal but 
can't be used to replace each other).

-- 
Joseph S. Myers
joseph@codesourcery.com