[clang] [clang][Interp] Only evaluate the source array initialization of an `ArrayInitLoopExpr` once (PR #68039)

[Timm Baeder via cfe-commits]

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@@ -827,6 +829,9 @@ bool ByteCodeExprGen<Emitter>::VisitArrayInitLoopExpr(
 
 template <class Emitter>
 bool ByteCodeExprGen<Emitter>::VisitOpaqueValueExpr(const OpaqueValueExpr *E) {
+  if (OpaqueExprs.contains(E))
+    return this->emitGetLocal(*classify(E), OpaqueExprs[E], E);
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tbaederr wrote:

Can `E` be of  composite type? If so, we need to handle that. If not,  you can just use `classifyPrim` instead.

This code also potentially does two lookups. you should do `auto It = OpaqueExprs.find(E); It != OpaqueExprs.end()) {`

https://github.com/llvm/llvm-project/pull/68039