Generate code for the move assignment operator using memcpy, the same as we do

for the copy assignment operator.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190385 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CodeGenFunction.cpp

@@ -702,7 +702,8 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
     // clones the body of the function call operator (but is actually static).
     EmitLambdaStaticInvokeFunction(cast<CXXMethodDecl>(FD));
   } else if (FD->isDefaulted() && isa<CXXMethodDecl>(FD) &&
-             cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator()) {
+             (cast<CXXMethodDecl>(FD)->isCopyAssignmentOperator() ||
+              cast<CXXMethodDecl>(FD)->isMoveAssignmentOperator())) {
     // Implicit copy-assignment gets the same special treatment as implicit
     // copy-constructors.
     emitImplicitAssignmentOperatorBody(Args);

test/CodeGenCXX/move-assignment.cpp

@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -emit-llvm -std=c++11 -o - %s -triple x86_64-pc-linux-gnu | FileCheck %s
+
+struct A {
+  A &operator=(A&&);
+};
+
+struct B {
+  A a;
+  int i;
+  bool b;
+  char c;
+  long l;
+  float f;
+};
+
+void test1() {
+  B b1, b2;
+  b1 = static_cast<B&&>(b2);
+}
+
+// CHECK-LABEL: define {{.*}} @_ZN1BaSEOS_
+// CHECK: call {{.*}} @_ZN1AaSEOS_
+// CHECK-NOT: store
+// CHECK: call {{.*}}memcpy{{.*}}, i64 24
+// CHECK-NOT: store
+// CHECK: ret