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[Bug tree-optimization/78731] [5 Regression] Possible bug with switch when optimization is turned on.
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 13 Dec 2016 09:14:33 +0000
- Subject: [Bug tree-optimization/78731] [5 Regression] Possible bug with switch when optimization is turned on.
- Auto-submitted: auto-generated
- References: <bug-78731-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78731
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> ---
On Fri, 9 Dec 2016, law at redhat dot com wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78731
>
> Jeffrey A. Law <law at redhat dot com> changed:
>
> What |Removed |Added
> ----------------------------------------------------------------------------
> CC| |law at redhat dot com
>
> --- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
> I'm convinced that a table based jump threader that traverses backedges is
> fundamentally a bad idea. That's why I ripped it out and we rely on
> Sebastian's code to handle those cases -- Sebastian's code doesn't have to deal
> with table invalidation.
>
> You might consider just disabling threading across the backedges. There'll be
> testsuite fallout, but in the end the layers upon layers of complexity to deal
> with invalidation just isn't worth it.
I don't think that's appropriate on the branch. So I appreciate review
of the patch I posted.