[llvm] [ConstantFolding] Fold vector reduce `fmax` and `fmin` intrinsics (PR #143904)

[Yingwei Zheng via llvm-commits]

https://github.com/dtcxzyw commented:

Can you add a test case with zero input?
The special handling for ConstantAggregateZero should be updated:
https://github.com/llvm/llvm-project/blob/4903c11a7e144d63635b115d97936a7aecf7a2f6/llvm/lib/Analysis/ConstantFolding.cpp#L2011-L2014


https://github.com/llvm/llvm-project/pull/143904