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

[Joshua Cranmer via llvm-commits]

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@@ -19407,12 +19430,12 @@ The '``llvm.vector.reduce.fmax.*``' intrinsics do a floating-point
 matches the element-type of the vector input.
 
 This instruction has the same comparison semantics as the '``llvm.maxnum.*``'
-intrinsic. That is, the result will always be a number unless all elements of
-the vector are NaN. For a vector with maximum element magnitude 0.0 and
-containing both +0.0 and -0.0 elements, the sign of the result is unspecified.
+intrinsic.  If the intrinsic call has the ``nnan`` fast-math flag, then the
+operation can assume that NaNs are not present in the input vector.
 
-If the intrinsic call has the ``nnan`` fast-math flag, then the operation can
-assume that NaNs are not present in the input vector.
+It is deprecated, since the different order of inputs may produce different
+outputs, and it is hard to optimize with Vector or SIMD extensions.
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jcranmer-intel wrote:

Nit: lower-case vector here (repeated for the other intrinsics).

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