[clang] [HLSL] Implement HLSL intialization list support (PR #123141)

[Chris B via cfe-commits]

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@@ -3173,9 +3173,18 @@ bool SemaHLSL::TransformInitList(const InitializedEntity &Entity,
   BuildFlattenedTypeList(InitTy, DestTypes);
 
   llvm::SmallVector<Expr *, 16> ArgExprs;
-  for (Expr *Arg : Init->inits())
-    if (!BuildInitializerList(SemaRef, Ctx, Arg, ArgExprs, DestTypes))
+  for (unsigned I = 0; I < Init->getNumInits(); ++I) {
+    Expr *E = Init->getInit(I);
+    if (E->HasSideEffects(Ctx)) {
+      QualType Ty = E->getType();
+      if (auto *RTy = Ty->getAs<RecordType>())
+        E = new (Ctx) MaterializeTemporaryExpr(Ty, E, E->isLValue());
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llvm-beanz wrote:

All AST node memory is owned by the ASTContext (hence the placement new-style syntax).

`E` is always owned by the ASTContext, I'm just shifting where in the AST it appears from being the top-level expression in the argument list to being a child of the MaterializeTemporary or OpaqueValue expression, which (at the end of the function) all gets rewritten over the original InitListExpr's Init expressions.

https://github.com/llvm/llvm-project/pull/123141