[llvm] [SDAG] Read-only intrinsics must have WillReturn attribute to be treated as loads (PR #99999)

[Jay Foad via llvm-commits]

jayfoad wrote:

> It seems malformed to me to permit an intrinsic that is treated as side-effect free, but also can exit the program.

An intrinsic that just loops potentially infinitely would be neither WillReturn nor HasSideEffects. (Not that I'm expecting anyone to define an intrinsic like that, but that's how the flags should be interpreted, for consistency with IR.)

https://github.com/llvm/llvm-project/pull/99999