[llvm] [NVPTX] Make i16x2 a native type and add supported vec instructions (PR #65432)

[Artem Belevich via llvm-commits]

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@@ -1262,10 +1264,11 @@ bool NVPTXDAGToDAGISel::tryLDGLDU(SDNode *N) {
     EltVT = EltVT.getVectorElementType();
     // vectors of f16 are loaded/stored as multiples of v2f16 elements.
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Artem-B wrote:

Comment needs updating/generalizing to 2-element vectors of 16-bit types.

https://github.com/llvm/llvm-project/pull/65432