[clang] [llvm] [HLSL] Implement dot2add intrinsic (PR #131237)

[Farzon Lotfi via llvm-commits]

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@@ -4894,7 +4894,7 @@ def HLSLDotProduct : LangBuiltin<"HLSL_LANG"> {
 def HLSLDot2Add : LangBuiltin<"HLSL_LANG"> {
   let Spellings = ["__builtin_hlsl_dot2add"];
   let Attributes = [NoThrow, Const, CustomTypeChecking];
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farzonl wrote:

Not sure what you mean. Are you saying you are seeing a crash when you run `clang/test/CodeGenHLSL/builtins/dot2add.hlsl` or does the test case not pass? Is it unhappy with the cases that don't use `-fnative-half-type` or does that flag not affect the result?

My theory is maybe the fact that HLSL treats halfs as floats without `-fnative-half-type` might be casuing a problem but don't feel like there is enoug information.

https://github.com/llvm/llvm-project/pull/131237