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] Get rid of awkward precision for bitsize types

From: Eric Botcazou <ebotcazou at adacore dot com>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: gcc-patches at gcc dot gnu dot org
Date: Mon, 6 Apr 2009 13:08:41 +0200
Subject: Re: [PATCH] Get rid of awkward precision for bitsize types
References: <200904061224.16916.ebotcazou@adacore.com> <200904061248.06957.ebotcazou@adacore.com> <84fc9c000904060347h75e95926x77bbeb3ca83a32b1@mail.gmail.com>

> But it would have the same problem, no?

Truncating or not truncating at run time doesn't change anything since we 
pretend that sizetypes don't overflow.  This worked perfectly before the 
bitfield truncating patch from 2004, it purely pessimized for sizetypes.

> How do we end up with computations in bitsizetype being expanded anyway?  I
> suppose for expansion we want to use the _UNIT variants of everything?

For variable-sized types, both TYPE_SIZE and TYPE_SIZE_UNIT can be big 
expressions which are gimplified; at -O0 nothing cleans up the mess.

-- 
Eric Botcazou

Follow-Ups:
- Re: [PATCH] Get rid of awkward precision for bitsize types
  - From: Richard Guenther

References:
- [PATCH] Get rid of awkward precision for bitsize types
  - From: Eric Botcazou
- Re: [PATCH] Get rid of awkward precision for bitsize types
  - From: Eric Botcazou
- Re: [PATCH] Get rid of awkward precision for bitsize types
  - From: Richard Guenther

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