[llvm] TTI: Check legalization cost of add/sub overflow ISD nodes (PR #100518)

[David Green via llvm-commits]

davemgreen wrote:

> LGTM - @davemgreen any concerns about the cost changes?

All these looked OK from an Arm/AArch64 point of view. I think it was the first patch in the series that was the most difficult.

https://github.com/llvm/llvm-project/pull/100518