[clang] [clang] Set correct FPOptions if attribute 'optnone' presents (PR #85605)

[Zahira Ammarguellat via cfe-commits]

zahiraam wrote:

I have uploaded your patch and compared the attributes generated from your patch and the little test case from https://github.com/llvm/llvm-project/issues/62098.  The attributes generated are different. Therefore, the expected optimizations from this patch are going to be different than what we currently have. I think that's a problem.

Attributes with this patch (only the ones that differ):

attributes #0 = { "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "unsafe-fp-math"="false" }

and without the patch:
attributes #0 = { "no-infs-fp-math"="true" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "unsafe-fp-math"="true" }


https://github.com/llvm/llvm-project/pull/85605