------- Comment #3 from law at redhat dot com 2005-12-15 02:53 -------
Subject: Re: [4.1/4.2 Regression] infinite
loop in dse
On Tue, 2005-12-13 at 00:23 +0000, pinskia at gcc dot gnu dot org wrote:
>
> ------- Comment #2 from pinskia at gcc dot gnu dot org 2005-12-13 00:23
> -------
> I am going to say this is 4.1 regression as it worked in 4.0.0 when removing
> the -fno-tree-copy-prop option but fails on the mainline and 4.1 branche with
> it. Somehow or another someone could come up with a testcase which fails also
> without any options which turn off optimizations (it is just harder to come up
> with one).
I just checked in the attached patch to the 4.1 branch. I'm testing the
same patch for mainline now.
Basically we had a PHI node which both used and defined the same
SSA_NAME (which can only occur at the head of a loop where the
SSA_NAME is an invariant and copies have not been fully propagated).
The safe thing to do is not try and optimize this case.
------- Comment #4 from law at redhat dot com 2005-12-15 02:54 -------
Created an attachment (id=10491)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10491&action=view)
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23838
