[llvm] [AArch64][CostModel] Alter sdiv/srem cost where the divisor is constant (PR #123552)

[Sushant Gokhale via llvm-commits]

sushgokh wrote:

> @sushgokh Now that 122469 is in, this should be able to test sve costs correctly if you can give it a rebase. We can hopefully move this forward.

Thanks @davemgreen for the 122469 patch. 

For your udiv/urem patch, I could see change in codegen when the constants are negative. I anticipate similar change here as well. I will soon get back the data and concerned changes as well.

https://github.com/llvm/llvm-project/pull/123552