[clang] [llvm] [InstCombine] fold float clamp pattern into llvm.max/min (PR #159652)

[Matt Arsenault via cfe-commits]

https://github.com/arsenm commented:

On second thought, why does instcombine need to do this? Don't we already do this late, in CodeGenPrepare or DAGBuilder? The exact min/max operation you want will be target dependent, and this is introducing new constraints to the operation 

https://github.com/llvm/llvm-project/pull/159652