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

[Nikita Popov via llvm-commits]

nikic wrote:

Unfortunately this broke from Objective C tests, which appears to rely on optimizations still happening for allocas. It inserts its own optimization barriers using inline asm.

So I looks like we do have to special case the alloca case if we want to preserve those Objective C optimizations. It's somewhat iffy though, because LLVM can promote globals to allocas. I'd be happy to adjust the tests with the optimization regressions instead...

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