[PATCH] D49519: [RegisterCoalescer] Delay live interval update work until the rematerialization for all the uses from the same def is done

[Wei Mi via Phabricator via llvm-commits]

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In https://reviews.llvm.org/D49519#1167444, @MatzeB wrote:

> Having invalid intermediate live ranges seems scary, and I'm not naturally convinced this is fine. How much have you tested this change yet?


The invalid live ranges are postponing to shrink some live ranges, so it is a conservative approach and shouldn't affect correctness, right? About the test, I set LateRematUpdateThreshold by default to 0 and bootstrap clang, then run through internal performance test. No correctness regression found.

Although there is performance perturbation in performance testing, that is within our expectation because failing to shrink live range in time could potentially hurt performance. That is why I choose to apply the change with a threshold.


Repository:
  rL LLVM

https://reviews.llvm.org/D49519