This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [PATCH] Fix PR28268, ICE building vector const { 1, 1 }

From: Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>
To: Ian Lance Taylor <iant at google dot com>
Cc: gcc-patches at gcc dot gnu dot org, Richard Guenther <rguenther at suse dot de>
Date: Thu, 06 Jul 2006 18:00:54 +0200
Subject: Re: [PATCH] Fix PR28268, ICE building vector const { 1, 1 }
References: <Pine.LNX.4.64.0607061212200.4374@nyjnma.fhfr.qr> <m3psgiivvc.fsf@localhost.localdomain>

This makes me uncomfortable.  The number zero seems like a special
case which merits special handling.  The number one does not.  What
you are looking for is a function which returns the multiplicative
identity for TYPE.  Currently you are getting it by calling
fold_convert (TYPE, integer_one_node).  Suppose you write the
multiplicative identify function, and handle VECTOR_TYPE there, rather
than making the number one a special case in fold_convert?

I agree, and there is indeed already get_one_constant in tree-ssa-math-opts.c.

I'd suggest that you move it to fold-const.c and use it.

I think -1 is way more "special" than 1. It is not stretching the argument as much as 1, because it is always "all ones".

Paolo

Follow-Ups:
- Re: [PATCH] Fix PR28268, ICE building vector const { 1, 1 }
  - From: Richard Guenther

References:
- [PATCH] Fix PR28268, ICE building vector const { 1, 1 }
  - From: Richard Guenther
- Re: [PATCH] Fix PR28268, ICE building vector const { 1, 1 }
  - From: Ian Lance Taylor

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]