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Re: GCC 3.1 Prerelease
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Peter Schmid <schmid at snake dot iap dot physik dot tu-darmstadt dot de>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Cc: jason at redhat dot com, rth at redhat dot com
- Date: Sat, 20 Apr 2002 17:24:15 -0700
- Subject: Re: GCC 3.1 Prerelease
- References: <Pine.LNX.4.30.0204210235010.13395-100000@snake.iap.physik.tu-darmstadt.de>
--On Sunday, April 21, 2002 02:35:57 AM +0200 Peter Schmid
<schmid@snake.iap.physik.tu-darmstadt.de> wrote:
> In my option PR c++/5504, a gcc 3.0 regression, is a critical bug
> which should be fixed for the upcoming gcc 3.1 release. Otherwise
> blitz will not compile on systems with less than 1.2 GB of virtual
> memory, for this small example. A full blown program will contain much
> more user code requiring even more memory.
This is a compile-time performance regression caused by fixing a
correctness bug. Correctness trumps; if we can't be both efficient
and correct, we should be correct, within reason. (And here lots of
programs still compile efficiently; some heavily inlined programs are now
taking more memory to compile.)
I don't quite understand Richard's last note on the topic -- but I
understand his conclusion, which is basically that it's not easy to
fix this problem. It sounds like maybe if the front end were to
promise that there were no gotos in a particular function, this would
improve things, but I'm not sure.
Jason, Richard, what do you think about this? The only practical
option, beyond the speedups Richard already implemented, is to
revert Jason's correctness patch at this point.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com