[PATCH] D73832: Ignore/Drop droppable uses for code-sinking in InstCombine

[Tyker via Phabricator via llvm-commits]

Tyker added a comment.

In D73832#1933035 <https://reviews.llvm.org/D73832#1933035>, @nikic wrote:

> Just a general question from my side: In what direction is this heading?
>
> Is this particular transform (InstCombine code sinking) something where assumes were observed to be problematic in practice? Or is this more of a proof-of-concept that will be extended to other one-use checks in InstCombine? (There's a lot of them, and I'm slightly concerned about the amount of boilerplate that would have to be introduced to handle this everywhere.)


this is intended as a proof of concept, code-sinking seemed like an easy place to start. I agree with you that extending it to all of instcombine not going to be easy particularly on the testing side.
but we are going to add more assumes with patches like D75825 <https://reviews.llvm.org/D75825> (disabled by default for now). so we need to minimize the negative impact of assume on other transformations. it is easier to do for assume with operand bundles rather than boolean assumes.


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