[clang] [HLSL] Add matrix support for isnan() and isinf() (PR #195586)

[Kaitlin Peng via cfe-commits]

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@@ -5709,13 +5709,13 @@ def HLSLFrac : LangBuiltin<"HLSL_LANG"> {
 
 def HLSLIsinf : LangBuiltin<"HLSL_LANG"> {
   let Spellings = ["__builtin_hlsl_elementwise_isinf"];
-  let Attributes = [NoThrow, Const];
+  let Attributes = [NoThrow, Const, CustomTypeChecking];
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kmpeng wrote:

+1. Also I'm guessing this change is why you had to delete tests from `isinf-errors.hlsl` and `isnan-errors.hlsl`, which I don't think you should be touching in a matrix PR.

https://github.com/llvm/llvm-project/pull/195586