[Bug tree-optimization/30052] [4.2/4.3 Regression] possible quadratic behaviour.

["dberlin at dberlin dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #41 from dberlin at gcc dot gnu dot org  2007-06-11 15:40 -------
Subject: Re:  [4.2/4.3 Regression] possible quadratic behaviour.

On 11 Jun 2007 14:17:46 -0000, rguenth at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #40 from rguenth at gcc dot gnu dot org  2007-06-11 14:17 -------
> And again, a 4.2/4.3 regression wrt compile-time _and_ memory-usage.  Mainline
> needs 1.2GB ram and whatnot time, 4.1 is happy with 500MB and about 10s.

Memory usage is just going to be up because we keep the last points-to
sets to propagate only differences.

It will take roughly twice as much memory.

This is just the cost of doing business faster.

I'll work on the time regression.

And please change the summary of this bug to something sane like
"points-to analysis too slow"

The algorithm is cubic in the worst case, and you simply can't do
anything about this.
:)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30052