Re: [C++ PATCH] Fix alignment handling in build_cplus_array_type/cp_build_qualified_type_real (PR c++/65690)

[Jakub Jelinek <jakub@redhat.com>]

On Thu, Apr 09, 2015 at 10:48:29AM -0400, Jason Merrill wrote:
> So the first hunk of the first patch is OK.

Ok, I've committed this to fix the regression.

2015-04-09  Jakub Jelinek  <jakub@redhat.com>

	PR c++/65690
	* tree.c (build_cplus_array_type): Layout type before variants are
	set, but copy over TYPE_SIZE and TYPE_SIZE_UNIT from the main
	variant.

	* c-c++-common/attr-aligned-1.c: New test.

--- gcc/cp/tree.c.jj	2015-04-01 15:29:33.000000000 +0200
+++ gcc/cp/tree.c	2015-04-08 09:09:45.326939354 +0200
@@ -880,12 +880,19 @@ build_cplus_array_type (tree elt_type, t
 	{
 	  t = build_min_array_type (elt_type, index_type);
 	  set_array_type_canon (t, elt_type, index_type);
+	  if (!dependent)
+	    {
+	      layout_type (t);
+	      /* Make sure sizes are shared with the main variant.
+		 layout_type can't be called after setting TYPE_NEXT_VARIANT,
+		 as it will overwrite alignment etc. of all variants.  */
+	      TYPE_SIZE (t) = TYPE_SIZE (m);
+	      TYPE_SIZE_UNIT (t) = TYPE_SIZE_UNIT (m);
+	    }
 
 	  TYPE_MAIN_VARIANT (t) = m;
 	  TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
 	  TYPE_NEXT_VARIANT (m) = t;
-	  if (!dependent)
-	    layout_type (t);
 	}
     }
 
--- gcc/testsuite/c-c++-common/attr-aligned-1.c.jj	2015-04-08 09:22:46.181427189 +0200
+++ gcc/testsuite/c-c++-common/attr-aligned-1.c	2015-04-08 09:26:41.315627195 +0200
@@ -0,0 +1,22 @@
+/* PR c++/65690 */
+/* { dg-do run } */
+
+typedef double T[4][4] __attribute__((aligned (2 * __alignof__ (double))));
+void foo (const T);
+struct S { T s; };
+
+int
+main ()
+{
+  if (__alignof__ (struct S) != 2 * __alignof__ (double)
+      || __alignof__ (T) != 2 * __alignof__ (double)
+      || __alignof__ (const struct S) != 2 * __alignof__ (double))
+    __builtin_abort ();
+  return 0;
+}
+
+#if defined(__cplusplus) && __cplusplus >= 201103L
+static_assert (alignof (S) == 2 * alignof (double), "alignment of S");
+static_assert (alignof (T) == 2 * alignof (double), "alignment of T");
+static_assert (alignof (const S) == 2 * alignof (double), "alignment of const S");
+#endif

	Jakub