[PATCH] D89095: AMDGPU: Introduce a flag to control enable/disable instruction sink pass

[Changpeng Fang via Phabricator via llvm-commits]

cfang added a comment.

In D89095#2325401 <https://reviews.llvm.org/D89095#2325401>, @nhaehnle wrote:

> I agree with Matt here. You should be able to do experiments locally. Perhaps sinking should be disabled entirely, or perhaps sinking should be improved to take register liveness into account.

Right, my point of view is that the Sink pass should be re-evaluated.  Since it has been introduced into AMDGPU pipeline many years ago, there must have been unexpected dependencies
on this pass.

Local experiments are absolutely necessary, but not sufficient.  I propose to introduce a flag  which could enable a broad range of experiments (from CQE for example). And then we can make decisions:

1. if it is mostly negative, we can disable it completely;
2. if it is mostly positive, we can keep it as it is;
3. if it it is in the middle, we can make effort to enhance it;


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https://reviews.llvm.org/D89095