[clang] [clang] Emit @llvm.assume before streaming_compatible functions when the streaming mode is known (PR #121917)

[Sander de Smalen via cfe-commits]

https://github.com/sdesmalen-arm commented:

@NickGuy-Arm this PR is missing some test-coverage.

@efriedma-quic do you have any thoughts on emitting the llvm.assume as a prologue to the actual call? I guess the alternative would be to analyse the function to see if there's any calls to streaming-compatible functions, and then emit the llvm.assume in the function's prologue or something, but that would be more work (and I'm not sure if that's worth it).

https://github.com/llvm/llvm-project/pull/121917