[PATCH] D15537: limit the number of instructions per block examined by dead store elimination

[Xinliang David Li via llvm-commits]

On Tue, Aug 23, 2016 at 1:20 PM, Daniel Berlin <dberlin at dberlin.org> wrote:
>>
>> While implementing caching is possible, I think we should avoid
>> reinventing the wheel in memorySSA, but to keep the fix as simple as
>> possible.  The new limit can be adjusted higher as its meaning has
>> changed.
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>
> I'd be more okay with your last argument if you were going to commit to
> rewriting this pass to MemorySSA.
> :)

Definitely committed -- no question about it :)  I don't think we have
any choice actually, but patches like this do allow buy us more time
to do so.


>
> If we have no-one committed to moving the pass, and no plans to implement
> caching, i guess my answer is "hope that someone will move this to MemorySSA
> one day is not a strategy".

that is right.

For this patch, I considered it high priority because there are so
many people got hit by the same issue again and again. The most recent
clang hanging problem in building chromium is a recent example.

David

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