[PATCH] D73882: CodeGen: Add TIED_COPY instruction

[Nicolai Hähnle via Phabricator via llvm-commits]

nhaehnle added a comment.

Do you have a use case for this, or can you explain a bit more what this solves, perhaps with an example?

Normal waterfall loops ought to be solved in the same way as any other loop with divergent exit: a value written inside the loop is observed from outside the loop, so there should be a COPY to a vgpr / vector register bank if necessary, but then the regular register allocation etc. does the rest. We don't need a TIED_COPY there today, or rather, I don't think we should  need one.


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  https://reviews.llvm.org/D73882/new/

https://reviews.llvm.org/D73882