[llvm] [AArch64] Check for immediates using isLegalICmpImmediate (PR #140999)

[Craig Topper via llvm-commits]

topperc wrote:

Your title says `isLegalICmpImmediate` which is the name of a function in TargetTransformInfo, but this patch doesn't use that function.

https://github.com/llvm/llvm-project/pull/140999