[clang] [HLSL][Matrix] introduce MatrixElementExpr as accessor and swizzle operator (PR #171225)

[Bruno Cardoso Lopes via cfe-commits]

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@@ -379,6 +379,8 @@ class ScalarExprEmitter : public StmtVisitor<ScalarExprEmitter, mlir::Value> {
 
   mlir::Value VisitExtVectorElementExpr(Expr *e) { return emitLoadOfLValue(e); }
 
+  mlir::Value VisitMatrixElementExpr(Expr *e) { return emitLoadOfLValue(e); }
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bcardosolopes wrote:

Unless you add a CIR testcase for this, the current approach is to mark this as unimplemented with an errorNYI call

https://github.com/llvm/llvm-project/pull/171225