Re: sparse-next and preview of 0.5.1-rc5

[Christopher Li <sparse@chrisli.org>]

On Sat, Jul 15, 2017 at 2:22 PM, Luc Van Oostenryck
<luc.vanoostenryck@gmail.com> wrote:
> [Sorry, I'm on vacation and very little computer access].

I am very glad to heard that you are back.

>
> I still object to the kill_unreachable_bbs() patch and I ask
> to reconsider it in favor of the original one.

Of course.  I will hold the RC5 for you. I haven't push the change to
master yet. It is only in sparse-next, I can still roll back the change in we
wants to.

Can you show me some C input file that your original patch will do the
right thing and current one will miss the opportunity to simplify?
Even for the case it is just a suspect of producing worse code is fine.
Just point me to some test case, I will investigate and compare the
results.

My guess is that, there is a good chance some where missing a simplify
opportunity. If it does make a difference and I can't fix it in a timely manner.
Let's use your patch and deal with it after the release. In the long run, I
would prefer not using the two pass deletion of the dead bb, if they can
produce the similar level of optimized result.

> Since this has already been discussed, I can only invite to read
> again the original patch and the one it fixes where the situation
> is explained, I think, clearly.

The original patch does not have test case showing the byte code
difference with this two approach. I need some test examples :-)

Again, glad to know that you are back.

Chris