[llvm] InstCombine: Handle extractelement in SimplifyDemandedFPClass (PR #174081)

[Matt Arsenault via llvm-commits]

arsenm wrote:

nofpclass doesn't need to directly mark the frexp. Simplification rooted on one of the users can still benefit by pushing through the frexp 

https://github.com/llvm/llvm-project/pull/174081