[PATCH] D125335: Give option to use isCopyInstr to determine which MI is treated as Copy instruction in MCP

[Xin Tong via Phabricator via llvm-commits]

adriantong1024 added a comment.

In D125335#3531767 <https://reviews.llvm.org/D125335#3531767>, @dmgreen wrote:

> I hadn't expected MachineCopyPropgation would be too expensive - it sounds like a simple concept and seems to already be run twice in the default pipeline. This is only adding an extra at -O3, so hopefully won't be too bad for compile time.
>
> Perhaps it is worth running some quick tests though? And if it is a problem adding `disablePass(&MachineCopyPropagationID);` for AArch64, to run just at the new pass location, not the old. I'm not sure if that would have any knock-on effects, disabling the two existing runs of the pass earlier in the pipeline.

Thanks for the comment @dmgreen. I will run some workload with and without the additional pass in AArch64 and report compilation time here.


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  https://reviews.llvm.org/D125335/new/

https://reviews.llvm.org/D125335