[compiler-rt] Bfi precision (PR #66285)

[David Li via llvm-commits]

david-xl wrote:

> BTW @xur-llvm could you take a look at `test/Transforms/PGOProfile/bfi_verification.ll`: It seems you added a flag to quantify/print the inaccuracies present in BFI data and well with my change here things aren't inaccurate anymore and the test no longer prints anything. I am not sure what to do with this except disable the test for now...

This test catches a diff close 4%. Is it intended to be considered ok with this patch?

To save the test, it is possible to modify the profile data fed to the test case with smaller PGO block counts.

https://github.com/llvm/llvm-project/pull/66285