[PATCH] D71696: [CodeGen] WIP MachinePostRAUpdater

[Sam Parker via Phabricator via llvm-commits]

samparker added a comment.

No, another pass won't help here. The point of this class is to allow transforms to use ReachingDefAnalysis while changing the code at the same time, not something a pass is useful for. But it should indeed be useful for DCE. ReachingDefAnalysis could(?) be modified to re-evaluate new instructions, but I don't think general queries about being able to move instructions fits into the analysis. In the context of low-overhead loops, we still need specific information from that analysis, such as instructions to ignore, to be able to do anything useful. For instance, we have cases where we want to remove 'redundant' mov instructions but, without knowing that the loop control instructions get removed, then those movs wouldn't be dead according to this class.


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  https://reviews.llvm.org/D71696/new/

https://reviews.llvm.org/D71696