[clang] [HLSL] Vector standard conversions (PR #71098)

[John McCall via cfe-commits]

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@@ -361,6 +361,9 @@ CAST_OPERATION(AddressSpaceConversion)
 // Convert an integer initializer to an OpenCL sampler.
 CAST_OPERATION(IntToOCLSampler)
 
+// Truncate a vector type (HLSL only).
+CAST_OPERATION(HLSLVectorTruncation)
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rjmccall wrote:

Okay.  I think this patch overall looks fine to land, except please do expand on the comment here to explain what truncating a vector type means (dropping elements from the end).

https://github.com/llvm/llvm-project/pull/71098