[llvm] [InstCombine] Fold more 'fcmp' 'select' instrs idioms into 'fabs' (PR #83381)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

I'm wondering whether we should be propagating the function-level attributes to instruction flags *somewhere* so that this is handled generically, rather than in individual folds?

https://github.com/llvm/llvm-project/pull/83381