[clang] [HLSL][Matrix] Add APValue and ConstExpr evaluator support for matrices (PR #178762)

[Deric C. via cfe-commits]

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@@ -6463,6 +6463,9 @@ static bool isZeroInitialized(QualType T, const APValue &V) {
     return true;
   }
 
+  case APValue::Matrix:
+    llvm_unreachable("Matrix APValues not yet supported");
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Icohedron wrote:

The function `isZeroInitialized` is only reachable from a call to `mangleValueInTemplateArg` which is only called in the context of non-type template arguments (NTTP). HLSL does not support NTTPs which is a C++20 feature.

https://github.com/llvm/llvm-project/pull/178762