[PATCH] D22639: Add flag to PassManagerBuilder to disable GVN Hoist Pass.

[Hans Wennborg via llvm-commits]

On Thu, Jul 21, 2016 at 3:49 PM, Daniel Berlin via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
>
> On Thu, Jul 21, 2016 at 12:43 PM, Benjamin Kramer <benny.kra at gmail.com>
> wrote:
>>
>> bkramer added a subscriber: bkramer.
>> bkramer added a comment.
>>
>> The problem is not a Halide test but a scalability issue in MemorySSA
>> that's making Halide unusable, consuming gigabytes of memory and taking
>> forever.
>>
>>
>>
>> Personally, I don't think the GVNHoist pass is ready for prime time yet
>> and needs more testing, like we did for other passes that were first
>> rigorously tested under a flag before being enabled by default. Going
>> directly from zero to default with a major new optimization infrastructure
>> (MemSSA) is a recipe for disaster.
>
>
> I agree that GVNHoist probably should not be on by default yet regardless of
> anything else.

I've also run into issues (PR28606) and am concerned because the pass
landed recently before the 3.9 branch. Please keep me in the loop on
whether it gets disabled.

Cheers,
Hans