[llvm] [InlineCost] Disable cost-benefit when sample based PGO is used (PR #86626)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

I think reverting the patch is probably the best.  IIUC:

- @HaohaiWen's internal loads perform better with the cost-benefit analysis enabled for sample PGO.
- @helloguo's internal loads perform worse with the cost-benefit analysis enabled for sample PGO.
- I don't have numbers our internal loads right now although I do remember that most of the inlining opportunities are taken by the sample loader inliner `llvm/lib/Transforms/IPO/SampleProfile.cpp`.

In a case like this, I am inclined to ask those who do see benefits to manually turn on the cost-benefit analysis (i.e. `-mllvm -inline-enable-cost-benefit-analysis`).  IMHO, features turned on by default should benefit broad audience.

Thoughts?

https://github.com/llvm/llvm-project/pull/86626