[llvm] [NVPTX] Generalize and extend upsizing when lowering 8/16-bit-element vector loads/stores (PR #119622)

[Artem Belevich via llvm-commits]

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@@ -160,6 +163,76 @@ static bool Is16bitsType(MVT VT) {
           VT.SimpleTy == MVT::i16);
 }
 
+// When legalizing vector loads/stores, this function is called, which does two
+// things:
+// 1. Determines Whether the vector is something we want to custom lower,
+// std::nullopt is returned if we do not want to custom lower it.
+// 2. If we do want to handle it, returns three parameters:
+//    - unsigned int NumElts - The number of elements in the final vector
+//    - EVT EltVT - The type of the elements in the final vector
+//    - bool UpsizeElementTypes - Whether or not we are upsizing the elements of
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Artem-B wrote:

This seems redundant, as it's equivalent of (`EltVT` or `NumElts` changed).

https://github.com/llvm/llvm-project/pull/119622