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Re: Vector comparison

From: Richard Henderson <rth at redhat dot com>
To: Artem Shinkarov <artyom dot shinkaroff at gmail dot com>
Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, gcc-patches at gcc dot gnu dot org, Richard Guenther <richard dot guenther at gmail dot com>
Date: Mon, 16 Aug 2010 12:24:28 -0700
Subject: Re: Vector comparison
References: <AANLkTimDve4hPRY9NEHprfa9SDjUGRykgEM=mdDFKNQf@mail.gmail.com> <Pine.LNX.4.64.1008151839130.29384@digraph.polyomino.org.uk> <AANLkTik-AJj8VX0Thuiur=6Ct2dAFmNXKmR7UjmQccTc@mail.gmail.com>

On 08/15/2010 12:15 PM, Artem Shinkarov wrote:
> SSE and AltiVec at least define vector comparison result as a vector
> of 0 and -1. So I think that this would be an exotic architecture (but
> I'm not sure). Anyway, if the target returns boolean value, then the
> implementation of the hook should return constant vector of zeros for
> false and constant vector of -1-s for true.

MIPS isn't so exotic.  The result of a float-pair comparison is to
set a pair of condition codes.  One can then use a branch that examines
both CC results, or a special move instruction for the SELECT operation.

r~

Follow-Ups:
- Re: Vector comparison
  - From: Richard Henderson
- Re: Vector comparison
  - From: Nathan Froyd

References:
- Vector comparison
  - From: Artem Shinkarov
- Re: Vector comparison
  - From: Joseph S. Myers
- Re: Vector comparison
  - From: Artem Shinkarov

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