This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/15524] [4.0 Regression] jump threading on trees is slow with switch statements with large # of cases
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Nov 2004 16:46:42 -0000
- Subject: [Bug tree-optimization/15524] [4.0 Regression] jump threading on trees is slow with switch statements with large # of cases
- References: <20040518194300.15524.pinskia@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From law at redhat dot com 2004-11-03 16:46 -------
Subject: Re: [4.0 Regression] jump threading
on trees is slow with switch statements with large # of cases
On Wed, 2004-11-03 at 16:33 +0000, kazu at cs dot umass dot edu wrote:
> ------- Additional Comments From kazu at cs dot umass dot edu 2004-11-03 16:33 -------
> Richard,
>
> My patches to expand_case does not change its asymptotic behavior.
>
> Jeff,
>
> You might want to use SBITMAP instead of BITMAP in your patch to
> expand_case because the bitmap you construct will be dense, and you know
> its size in advance.
No you don't know it's size or density in advance. We're not looking
at case values, but at the label where each case statement will jump to.
Jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15524