From: "Adam J. Richter" <adam@yggdrasil.com>
Date: Thu, 12 Apr 2001 12:01:55 -0700
Message-Id: <200104121901.MAA04011@adam.yggdrasil.com>
To: johan.adolfsson@axis.com
Subject: Re: List of all-zero .data variables in linux-2.4.3 available
Cc: linux-kernel@vger.kernel.org
Sender: linux-kernel-owner@vger.kernel.org

johan.adolfsson@axis.com writes:
>Shouldn't a compiler be able to deal with this instead?

	Yes.  I sent some email to bug-gcc about this a couple of
months ago and even posted some (probably horribly incorrect) code
showing roughly the change I had in mind in the gcc source code
for the simple case of scalar variables.  I was told that some code
to this was put in and then removed from gcc a long time ago, and
nobody seemed interested in putting it back in.  I would think that this
would be a basic optimization that I would expect the compiler to make,
just like deleting "if(0) {......}" code, but gcc does not currently
do that.  If somebody would like to fix gcc and do the necessary
lobbying to get such a change integrated, that would be great.  However,
until that actually happens, I hope the file that I posted to
ftp://ftp.yggdrasil.com/private/adam/linux/zerovars/ will be useful
to individual maintainers and in identifying the largest arrays of
zeroes that can fix fixed in a few lines.

Adam J. Richter     __     ______________   4880 Stevens Creek Blvd, Suite 104
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