[llvm] [AArch64][LoopVectorize] Use upper bound trip count instead of the constant TC when choosing max VF (PR #67697)

[David Sherwood via llvm-commits]

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

Thanks for this @rin-arm! It looks like a nice improvement that makes greater use of information that the compiler already has. I just had a couple of minor comments regarding the test.

https://github.com/llvm/llvm-project/pull/67697