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.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139143 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 10 insertions, 12 deletions

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index b68e3388d6..bd788d0b0a 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -1069,7 +1069,9 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
     if (const RecordType *RT = Ty->getAs<RecordType>()) {
       CXXRecordDecl *Record = cast<CXXRecordDecl>(RT->getDecl());
       assert((Record->hasTrivialCopyConstructor() || 
-              Record->hasTrivialCopyAssignment()) &&
+              Record->hasTrivialCopyAssignment() ||
+              Record->hasTrivialMoveConstructor() ||
+              Record->hasTrivialMoveAssignment()) &&
              "Trying to aggregate-copy a type without a trivial copy "
              "constructor or assignment operator");
       // Ignore empty classes in C++.
diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index acc9a2b036..9f21abd20c 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -334,16 +334,12 @@ CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
   LValue LV = EmitLValue(E->getArg(0));
   llvm::Value *This = LV.getAddress();
 
-  if (MD->isCopyAssignmentOperator()) {
-    const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(MD->getDeclContext());
-    if (ClassDecl->hasTrivialCopyAssignment()) {
-      assert(!ClassDecl->hasUserDeclaredCopyAssignment() &&
-             "EmitCXXOperatorMemberCallExpr - user declared copy assignment");
-      llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
-      QualType Ty = E->getType();
-      EmitAggregateCopy(This, Src, Ty);
-      return RValue::get(This);
-    }
+  if ((MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) &&
+      MD->isTrivial()) {
+    llvm::Value *Src = EmitLValue(E->getArg(1)).getAddress();
+    QualType Ty = E->getType();
+    EmitAggregateCopy(This, Src, Ty);
+    return RValue::get(This);
   }
 
   llvm::Value *Callee = EmitCXXOperatorMemberCallee(E, MD, This);
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 04868cee57..d7db42494f 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/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);