[llvm] [LV][AArch64] Prefer Fixed over Scalable if cost-model is equal (Neoverse V2) (PR #95819)

[David Sherwood via llvm-commits]

david-arm wrote:

> There is nothing fundamentally wrong with LLVM's codegen, but it performs a lot worse.

Does that in fact suggest for this case that we should be interleaving less in LLVM and be tuning that accordingly? GCC's output does use NEON, but there is no interleaving. Have you tried disabling interleaving when using SVE in LLVM so that it's a fairer comparison with GCC? I'd be interested to know how that performs.

https://github.com/llvm/llvm-project/pull/95819