[llvm] LangRef: Clarify llvm.minnum and llvm.maxnum about sNaN and signed zero (PR #112852)

[YunQiang Su via llvm-commits]

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@@ -16723,21 +16723,29 @@ type.
 
 Semantics:
 """"""""""
+Follows the semantics of minimumNumber in IEEE-754-2019, except for signaling NaNs. If either operand
+is an sNaN, the result is always a qNaN. This matches the recommended behavior for the libm
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wzssyqa wrote:

I also prefer describe it with IEEE-754-2008 as base.

https://github.com/llvm/llvm-project/pull/112852