[PATCH] D96881: [InstCombine] Avoid Bitcast-GEP fusion for pointers directly from allocation functions

[Eric Christopher via llvm-commits]

On Thu, Mar 25, 2021 at 1:27 AM Eric Christopher <echristo at gmail.com> wrote:

>
>
> On Tue, Mar 23, 2021 at 5:38 PM Nikita Popov via Phabricator <
> reviews at reviews.llvm.org> wrote:
>
>> nikic added a comment.
>>
>> In D96881#2646035 <https://reviews.llvm.org/D96881#2646035>, @echristo
>> wrote:
>>
>> > In D96881#2627389 <https://reviews.llvm.org/D96881#2627389>, @nikic
>> wrote:
>> >
>> >> LGTM per above discussion. It's not ideal, but I think it's the best
>> we can do right now.
>> >
>> > Hi All,
>> >
>> > I'm seeing a rather numerous set of performance degredations and code
>> size increases on x86 with this patch. I think that's a little unexpected,
>> but do we have benchmarks and runs showing that this is a profitable change
>> to happen in general?
>>
>> If you're seeing widespread regressions, let's revert this change. My
>> assumption here was that it would fix the motivational case without
>> impacting anything else much, but apparently that's not the case.
>>
>>
> We're working on that. Some of the size increases are small but numerous
> which makes smallish testcases hard. The impact may not be too large if
> it's worth the long term maintenance.
>

Following back up here. I think we're ok here. Thanks for the offer and
sorry it took me so long to follow back up.

-eric
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