[llvm-branch-commits] [llvm] [llvm][dfa-jump-threading] Allow DFAJumpThreading with optsize (PR #83049)

[Paul Kirth via llvm-branch-commits]

ilovepi wrote:

> This pass is not part of the default pipeline -- do you enable this pass downstream, or do you want to add options for _all_ uses of minsize, even if there is no evidence of usefulness?

We’d like to see if this can be useful to some of our size constrained users in the embedded space. Particularly because it has been proposed to turn this on in the default pipeline.  https://discourse.llvm.org/t/rfc-enable-dfa-jumpthreading-pass-by-default/77231. Currently we don’t have evidence that this is beneficial, but for these targets we also don’t have a way to vet that with the current implementation.  

So to be concrete, I’d like the ability to enable this pass somehow even if compiling for size. If we can control this behavior with a threshold, then mechanically I don’t see much difference between that an the flags I’ve added in this pass.  But right now we don’t have a way to evaluate if this may be useful at any threshold, and I think it’s useful if we can turn this knob in some way without changing the default behavior. 

https://github.com/llvm/llvm-project/pull/83049