[PATCH] D92068: [MachineCombiner] Add MustReduceRegisterPressure goal

[ChenZheng via Phabricator via llvm-commits]

shchenz added a comment.

Thanks for your comments @spatel @lebedev.ri

Do you have any idea to run the `LiveIntervals` pass only on the target that MustReduceRegisterPressure is enabled? 
Some considerations:
1: PowerPC uses LiveIntervals in class `PPCInstrInfo` which is not inherited from class `Pass`, so I can not call `getAnalysis<LiveIntervals>()` there. 
2: I tried to guard `getAnalysis<LiveIntervals>()` in `MachineCombiner` pass under a new condition like `enableReduceRegisterPressureGoal()`, it also does not work. If we add `AU.addRequired<LiveIntervals>()` in `MachineCombiner::getAnalysisUsage`, we will need to add the required passes before machine combiner pass.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D92068/new/

https://reviews.llvm.org/D92068