[llvm] [llvm-mca] Round UP when formatting Reciprocal Throughput (PR #159544)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

This is a hack and not a principled solution to the underlying problem.

I don't think we're using anything other than the basic arithmetic operators inside of MCA to compute the value, so it should be bitwise identical between platforms assuming they are IEEE754 compliant and implement correct rounding on basic arithmetic operators. It would be good to understand why this platform difference exists (different default rounding modes? `format` implementation differences?) before papering over the issue with more arithmetic.

https://github.com/llvm/llvm-project/pull/159544