PR c++/90736 - bogus error with alignof.

	* constexpr.c (adjust_temp_type): Use cv_unqualified type.

	* g++.dg/cpp0x/alignof5.C: New test.

From-SVN: r272217

gcc/cp/ChangeLog

+2019-06-12  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/90736 - bogus error with alignof.
+	* constexpr.c (adjust_temp_type): Use cv_unqualified type.
+
 2019-06-11  Matthew Beliveau  <mbelivea@redhat.com>
 
 	PR c++/90449 - add -Winaccessible-base option.

gcc/cp/constexpr.c

@@ -1318,7 +1318,9 @@ adjust_temp_type (tree type, tree temp)
   if (TREE_CODE (temp) == EMPTY_CLASS_EXPR)
     return build0 (EMPTY_CLASS_EXPR, type);
   gcc_assert (scalarish_type_p (type));
-  return cp_fold_convert (type, temp);
+  /* Now we know we're dealing with a scalar, and a prvalue of non-class
+     type is cv-unqualified.  */
+  return cp_fold_convert (cv_unqualified (type), temp);
 }
 
 /* If T is a CONSTRUCTOR, return an unshared copy of T and any

gcc/testsuite/ChangeLog

+2019-06-12  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/90736 - bogus error with alignof.
+	* g++.dg/cpp0x/alignof5.C: New test.
+
 2019-06-12  Dimitar Dimitrov  <dimitar@dinux.eu>
 
 	* gcc.dg/builtin-apply2.c: Skip for PRU.

gcc/testsuite/g++.dg/cpp0x/alignof5.C

+// PR c++/90736 - bogus error with alignof.
+// { dg-do compile { target c++11 } }
+
+constexpr int fn(const int b) { return b; }
+constexpr int c = fn(alignof(int));
+alignas(c) char d;