2019-03-12  Jakub Jelinek  <jakub@redhat.com>

	PR c++/89660
	Revert:
	2019-03-06  Marek Polacek  <polacek@redhat.com>

	PR c++/87378 - bogus -Wredundant-move warning.
	* typeck.c (maybe_warn_pessimizing_move): See if the maybe-rvalue
	overload resolution would actually succeed.

	* g++.dg/cpp0x/Wredundant-move1.C (fn4): Drop dg-warning.

--- gcc/cp/typeck.c	(revision 269427)
+++ gcc/cp/typeck.c	(revision 269426)
@@ -9429,24 +9429,10 @@ maybe_warn_pessimizing_move (tree retval
 	     do maybe-rvalue overload resolution even without std::move.  */
 	  else if (treat_lvalue_as_rvalue_p (arg, /*parm_ok*/true))
 	    {
-	      /* Make sure that the overload resolution would actually succeed
-		 if we removed the std::move call.  */
-	      tree t = convert_for_initialization (NULL_TREE, functype,
-						   move (arg),
-						   (LOOKUP_NORMAL
-						    | LOOKUP_ONLYCONVERTING
-						    | LOOKUP_PREFER_RVALUE),
-						   ICR_RETURN, NULL_TREE, 0,
-						   tf_none);
-	      /* If this worked, implicit rvalue would work, so the call to
-		 std::move is redundant.  */
-	      if (t != error_mark_node)
-		{
-		  auto_diagnostic_group d;
-		  if (warning_at (loc, OPT_Wredundant_move,
-				  "redundant move in return statement"))
-		    inform (loc, "remove %<std::move%> call");
-		}
+	      auto_diagnostic_group d;
+	      if (warning_at (loc, OPT_Wredundant_move,
+			      "redundant move in return statement"))
+		inform (loc, "remove %<std::move%> call");
 	    }
 	}
     }
--- gcc/testsuite/g++.dg/cpp0x/Wredundant-move1.C	(revision 269427)
+++ gcc/testsuite/g++.dg/cpp0x/Wredundant-move1.C	(revision 269426)
@@ -59,8 +59,7 @@ T
 fn4 (const T t)
 {
   // t is const: will decay into copy despite std::move, so it's redundant.
-  // We used to warn about this, but no longer since c++/87378.
-  return std::move (t);
+  return std::move (t); // { dg-warning "redundant move in return statement" }
 }
 
 int