Use 2 phase dynamic load only for compound operations

mcs/mcs/expression.cs

@@ -8084,7 +8084,7 @@ namespace Mono.CSharp {
 			// Same cannot be done for reference type because array covariance and the
 			// check in ldelema requires to specify the type of array element stored at the index
 			//
-			if (t.IsStruct && (prepare_for_load || !TypeManager.IsPrimitiveType (t)) && !(source is DynamicExpressionStatement)) {
+			if (t.IsStruct && ((prepare_for_load && !(source is DynamicExpressionStatement)) || !TypeManager.IsPrimitiveType (t))) {
 				LoadArrayAndArguments (ec);
 				ec.EmitArrayAddress (ac);
 

mcs/tests/dtest-035.cs

@@ -66,6 +66,12 @@ public class Test
 		iar [0] += dvalue;
 		if (iar [0] != -11)
 			return 5;
+		
+		dynamic dn = 1;
+		int?[] array = new int?[1];
+		array[0] = dn;
+		if (array [0] != 1)
+			return 6;
 
 		Console.WriteLine ("ok");
 		return 0;

mcs/tests/ver-il-dmcs.xml

@@ -2276,7 +2276,7 @@
         <size>74</size>
       </method>
       <method name="Int32 Main()">
-        <size>1039</size>
+        <size>1181</size>
       </method>
       <method name="Void .ctor()">
         <size>18</size>