[clang] [HLSL] Implement HLSL Flat casting (excluding splat cases) (PR #118842)

[Sarah Spall via cfe-commits]

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@@ -14857,6 +14857,7 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
   case CK_FixedPointCast:
   case CK_IntegralToFixedPoint:
   case CK_MatrixCast:
+    // TODO does CK_HLSLAggregateCast belong here?
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spall wrote:

It can, and I do need to remove this comment. This will be implemented later.

https://github.com/llvm/llvm-project/pull/118842