[PATCH] tree-optimization/101014 - Remove poor value computations.

[Andrew MacLeod]

On 6/19/21 3:51 AM, Richard Biener wrote:
> On June 18, 2021 11:46:08 PM GMT+02:00, Andrew MacLeod <amacleod@redhat.com> wrote:
>> I am pleased to say that this patch kills the poor value computations
>> in
>> the ranger's cache.
>>
>> Its been a bit of a thorn, and is mostly a hack that was applied early
>> on to enable getting some opportunities that were hard to get
>> otherwise.
>>
>> The more consistent propagation we now do combined with other changes
>> means I can kill this wart on trunk. It even results in a 1% speedup..
>> and should resolve some of the excessive compile time issues causes by
>> undesirable iteration, including 101014.. for good I hope :-).
>>
>> I tried turning off the poor_value computations on the GCC11 branch,
>> and
>> we may want to consider doing it there too.  In my testsuite, we miss a
>>
>> total of 3 cases out of 4700 new ones identified by ranger.  For the
>> stability, I'd suggest we turn off poor_value computations there as
>> well.  This patch rips out all the code, but for GCC11 I'd just change
>> push_poor_value to always return false, thus never registering any
>> values. less churn that way. I'll run some tests and post that
>> separately if you think we should go ahead with it.
>>
>> Bootstraps on 86_64-pc-linux-gnu with no regressions.  pushed.
> Nice. I think we should indeed consider mostly syncing the algorithmic changes with GCC 11 to make maintenance easier, at least up to 11.2. Now, please leave such changes some time to bake on trunk before backporting.
>
> Thanks,
> Richard.
>
For sure.  Im accumulating the gcc11 patches, and will hold them for a 
bit yet.

Andrew