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Re: [PATCH] Don't clobber dominator info in the combiner (PR target/77526)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Segher Boessenkool <segher at kernel dot crashing dot org>
- Cc: Richard Biener <rguenther at suse dot de>, gcc-patches at gcc dot gnu dot org
- Date: Fri, 16 Sep 2016 01:41:37 +0200
- Subject: Re: [PATCH] Don't clobber dominator info in the combiner (PR target/77526)
- Authentication-results: sourceware.org; auth=none
- References: <20160915225044.GC7282@tucnak.redhat.com> <20160915232011.GA6920@gate.crashing.org>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Thu, Sep 15, 2016 at 06:20:11PM -0500, Segher Boessenkool wrote:
> On Fri, Sep 16, 2016 at 12:50:44AM +0200, Jakub Jelinek wrote:
> > As mentioned in the PR, combiner sometimes calls
> > purge_all_dead_edges or purge_dead_edges that can invalidate the dominator
> > info if it is computed. Other passes like CSE in that case free the
> > dominance info, this patch does the same in the combiner.
> >
> > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> Okay, but does it need the same for the post-dominators? Oh, those
> never exist longer than a single pass?
Yeah, indeed, passes that compute post-dominators are required to free them
as well, and combine doesn't.
Jakub