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Re: C constant expressions proposals

From: Mark Mitchell <mark at codesourcery dot com>
To: Joe Buck <Joe dot Buck at synopsys dot COM>
Cc: Robert Dewar <dewar at gnat dot com>, Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc at gcc dot gnu dot org
Date: Wed, 18 Aug 2004 10:19:06 -0700
Subject: Re: C constant expressions proposals
Organization: CodeSourcery, LLC
References: <10408181136.AA16529@vlsi1.ultra.nyu.edu> <412382A9.8070408@codesourcery.com> <41238477.7080100@gnat.com> <20040818101043.A4602@synopsys.com>

Joe Buck wrote:

On Wed, Aug 18, 2004 at 12:31:51PM -0400, Robert Dewar wrote:

I am confused. Full detection of undefined variables requires full
flow analysis and solution of data flow equations.

Agreed; you need lots of optimization to do a decent job of detection
of undefined variables.

Even data flow equations don't really suffice to do an accurate job,
as that approach misses correlations between branches.  Avoiding certain
common kinds of false positives would require something like gated single
assignment.

Heh, this is that discussion we've already had before.

I'm not going to fan the flames here.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com

Follow-Ups:
- Re: C constant expressions proposals
  - From: Robert Dewar

References:
- Re: C constant expressions proposals
  - From: Richard Kenner
- Re: C constant expressions proposals
  - From: Mark Mitchell
- Re: C constant expressions proposals
  - From: Robert Dewar
- Re: C constant expressions proposals
  - From: Joe Buck

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