[PATCH] Allow BB duplication threshold to be adjusted through JumpThreading's ctor

[Owen Anderson]

On Sep 29, 2014, at 5:10 PM, Hal Finkel <hfinkel at anl.gov> wrote:

>> For updating that threshold from TTI, yeah, if we are interested in
>> that case. I could come another patch considering both TTI and
>> user-specified threshold.
> 
> I suppose that I don't understand what you mean by "if we are interested." Generally speaking, ctor parameters are useful only for clients who are not using the standard optimization pipeline, and we'd like the standard optimization pipeline to generally work well for a wide range of targets. Thus, a TTI interface is preferred.

I strongly disagree with this reasoning.  We’re discussing GPU compilers, which typically on-line compilers, with sensitive compile time constraints.  The default pass pipelines are completely unsuitable for that use case.  Allowing the client to make the decision at pass pipeline construction time is very important, since only the client knows if it is compiling in a time sensitive environment or not.

—Owen


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