[llvm] [LoopVectorize] Add support for vectorisation of simple early exit loops (PR #88385)

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

> > I was wondering if it would be good to add some AArch64 codegen tests too so that we can look at some codegen?
> 
> If you're referring to the codegen coming out of clang after vectorising the loop, I don't think we typically have tests like that in test/Transform/LoopVectorize. They are normally IR/opt based tests. Are you referring specifically to the codegen from the cttz.elts intrinsic? If so, we already have tests for them - see CodeGen/AArch64/intrinsic-cttz-elts-sve.ll, for example.

Yes, I appreciate we test all things individually, but I was just thinking that it is a bit of shame we can't look at some codegen for a loop for all of this work. For example, take the resulting IR of some of the tests in test/Transform/LoopVectorize/AArch64, and create llc tests. Not sure if there's precedent for that, I guess not.

https://github.com/llvm/llvm-project/pull/88385