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Re: Long term code compactness regression
- To: Aaron Lehmann <aaronl at vitelus dot com>
- Subject: Re: Long term code compactness regression
- From: Jan Hubicka <jh at suse dot cz>
- Date: Sat, 27 Oct 2001 00:46:52 +0200
- Cc: gcc at gcc dot gnu dot org
- References: <20011026150938.C25756@vitelus.com>
> I compiled the Linux software package busybox with three different
> compiler versions on i386.
> compiler opt size
> gcc 18.104.22.168 -O2 213116
> gcc 2.95.4-pre -Os 216652
> gcc 3.0.2-pre -Os 222012
> Binaries were stripped, and the .note and .comment sections were
> This is indicating that gcc 22.214.171.124 does *better* with -O2 than 2.95
> and 3.x with -Os. If I broke these down to specific testcases and
> compared the assembly output, would anyone look at fixing the behavior
> of -Os?
Some of work has been already done at 3.1.x branch. See Andreas tester
http://www.suse.de/~aj/SPEC for development of size of binaries on mainline
that is mostly decreasing.
For i386, you may try -mpreferred-stack-boundary=2 that is the most common
cause of code size growth on 2.95.0+ compilers for i386.
In case you notice some simple enought testcases to fix, I would happily
look at it, as code size is definitly important parameter, but it would be
nice if you did it for mainline, as 3.0.x branch is not here to fix such