When performing a derived-to-base cast on the right-hand side of the

synthesized move assignment within an implicitly-defined move
assignment operator, be sure to treat the derived-to-base cast as an
xvalue (rather than an lvalue). Otherwise, we'll end up getting the
wrong constructor.

Optimize a direct call to a trivial move assignment operator to an
aggregate copy, as we do for trivial copy assignment operators, and
update the the assertion in CodeGenFunction::EmitAggregateCopy() to
cope with this optimization.

Fixes PR10860.

llvm-svn: 139143

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 04868cee576..d7db42494f5 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -7847,7 +7847,7 @@ void Sema::DefineImplicitMoveAssignment(SourceLocation CurrentLocation,
     // appropriately-qualified base type.
     Expr *From = OtherRef;
     From = ImpCastExprToType(From, BaseType, CK_UncheckedDerivedToBase,
-                             VK_RValue, &BasePath).take();
+                             VK_XValue, &BasePath).take();
 
     // Dereference "this".
     ExprResult To = CreateBuiltinUnaryOp(Loc, UO_Deref, This);