[llvm] [InlineCost] Consider the default branch when calculating cost (PR #77856)

[Quentin Dian via llvm-commits]

DianQK wrote:

> Can we slightly increase the inline threshold to fix the regression?

I will consider trying it.

> We need to understand what is no longer getting inlined and see whether there is either some optimization of cost modelling improvement we can make to compensate. (E.g. I think doing switch-to-arithmetic conversion pre-inline would be worthwhile.)

Yes, the example makes sense. I have created an issue for this and I will try to investigate at the end of the traveling.

https://github.com/llvm/llvm-project/pull/77856