re PR c++/57175 (NRVO and alignment)

2013-05-20  Marc Glisse  <marc.glisse@inria.fr>

	PR c++/57175
gcc/cp/
	* typeck.c (check_return_expr): Reverse the alignment comparison.

gcc/testsuite/
	* g++.dg/pr57175.C: New testcase.

From-SVN: r199093

gcc/cp/ChangeLog

+2013-05-20  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/57175
+	* typeck.c (check_return_expr): Reverse the alignment comparison.
+
 2013-05-17  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/18126

gcc/cp/typeck.c

@@ -8369,7 +8369,7 @@ check_return_expr (tree retval, bool *no_warning)
      && DECL_CONTEXT (retval) == current_function_decl
      && ! TREE_STATIC (retval)
      && ! DECL_ANON_UNION_VAR_P (retval)
-     && (DECL_ALIGN (retval) >= DECL_ALIGN (result))
+     && (DECL_ALIGN (retval) <= DECL_ALIGN (result))
      /* The cv-unqualified type of the returned value must be the
         same as the cv-unqualified return type of the
         function.  */

gcc/testsuite/ChangeLog

+2013-05-20  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/57175
+	* g++.dg/pr57175.C: New testcase.
+
 2013-05-17   Easwaran Raman  <eraman@google.com>
 
 	* gcc.dg/tree-ssa/reassoc-28.c: New testcase.

gcc/testsuite/g++.dg/pr57175.C

+/* { dg-do compile } */
+/* { dg-options "-std=c++11" } */
+
+extern "C" void do_not_remove ();
+
+struct A
+{
+  A () { }
+  A (A const&) { do_not_remove (); }
+};
+
+A
+f ()
+{
+  alignas (2 * alignof (A)) A x;
+  return x;
+}
+
+/* { dg-final { scan-assembler "do_not_remove" } } */