[llvm] [BasicAA] Treat returns_twice functions as clobbering unescaped objects (PR #117902)

[Nikita Popov via llvm-commits]

nikic wrote:

MemCpyOpt already uses BatchAA with EarliestEscapeAnalysis. I tried dropping callCapturesBefore() in https://github.com/llvm/llvm-project/pull/110484, but there were enough regressions on llvm-opt-benchmarks that I decided to keep it for now.

(We could remove callCapturesBefore while keeping its additional precision by adding a CaptureAnalysis using CapturesBefore, possibly in conjunction with support for "chained" capture analysis where we try EarliestEscapeAnalysis before falling back to CatpuresBeforeAnalysis.)

https://github.com/llvm/llvm-project/pull/117902