[clang] [llvm] [DropUnnecessaryAssumes] Add pass for dropping assumes (PR #159403)

[Nikita Popov via llvm-commits]

nikic wrote:

> Hi @nikic What if there is a later pass that needs the assume intrinsic? I have a case where I want to enable speculative devirtualization which depends on the presence of assume intrinsic and also depends on other passes that run (later in the pipeline).

Can you please provide some more details on how the assumes look like and what the phase ordering looks like? Devirtualization happening after this pass runs sounds fishy to me -- this pass runs post-inlining, and I'd expect devirtualization to occur pre-inlining (or interleaved) to be useful.

https://github.com/llvm/llvm-project/pull/159403