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

[Nicholas Guy via cfe-commits]

NickGuy-Arm wrote:

> The assumption cache mechanism is used by a number of passes...

@efriedma-quic @aemerson ping



> I'm not sure it's correct to mark int_aarch64_sme_in_streaming_mode IntrNoMem...

That's fair, I had mistakenly assumed `IntrNoMem` to mean "I don't touch memory". I'll put up a separate PR to change it to use `IntrReadMem` shortly.

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