Laurent GUERBY - Re: Null pointer check elimination (original) (raw)

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• From: Laurent GUERBY
• To: Robert Dewar , Richard Kenner , Diego Novillo
• Cc: gcc at gcc dot gnu dot org, Per Bothner , Anthony Green , java at gcc dot gnu dot org
• Date: Sat, 12 Nov 2005 18:40:53 +0100
• Subject: Re: Null pointer check elimination
• References: 1131747852.3205.105.camel@localhost.localdomain <437620D9.9090701@bothner.com> <1131816266.6774.940.camel@pc.site> <200511121230.35086.dnovillo@redhat.com>

On Sat, 2005-11-12 at 12:30 -0500, Diego Novillo wrote:

On Saturday 12 November 2005 12:24, Laurent GUERBY wrote:

Note that this correspond to the "not null" feature added to Ada 2006 in various places, including pointer type definitions:

type Ptr is not null access Integer;

Ah, this is different and it would be very helpful. If it's a language mandated thing, then VRP could just rely in this type attribute and default to 'non-zero' when it can't infer any other useful value.

Yes it's language mandated (well when the ISO Ada 2006 revision is out next year :), my guess is that the Ada front-end remove some of it's own checks based on this but that this information is not passed outside the front-end, may be Richard Kenner or Robert Dewar can comment on this.

Laurent

• References:
  • Re: Null pointer check elimination
    * From: Per Bothner
  • Re: Null pointer check elimination
    * From: Laurent GUERBY
  • Re: Null pointer check elimination
    * From: Diego Novillo