[llvm] [LVI][SCCP][CVP] Add basic ConstantFPRange support (PR #111544)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Another thing that stands out (though only tangentially related) is that the IEEEFloat/DoubleAPFloat dispatch that has to occur on every single APFloat operation requires an out of line call to fetch the PPCDoubleDouble() semantics :( I am curious why these are implemented as function calls returning a global, rather than directly exported globals.

https://llvm-compile-time-tracker.com/compare.php?from=e438bae71d1fd55640d942b9ad795de2f60e44f2&to=04751477940890c092dc4edb74e284de8f746d5a&stat=instructions:u

https://github.com/llvm/llvm-project/pull/111544