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

[Helena Kotas via cfe-commits]

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@@ -4472,6 +4543,59 @@ void ExtVectorElementExpr::getEncodedElementAccess(
   }
 }
 
+void MatrixElementExpr::getEncodedElementAccess(
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hekota wrote:

The functions `containsDuplicateElements` and `getEncodedElementAccess` seem to have a lot of common code. Consider moving the common part into a function with a lambda arg which would handle the calculated index. The lambda for `getEncodedElementAccess` would add the index to the list, and the lambda for `containsDuplicateElements` would check if it is a duplicate.

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