From d9d9dbc0d0d3a1f419115367cfe23992a92f822b Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Fri, 28 Sep 2007 14:07:57 -0400
Subject: [PATCH] re PR c++/10179 (alignment attributes are not inherited
 correctly with empty classes)

        PR c++/10179
        * class.c (layout_empty_base): Take rli parameter, update
        rli->record_align if empty base has user-specified alignment.
        (build_base_field): Pass rli to it.

From-SVN: r128871
---
 gcc/cp/ChangeLog                  |  8 ++++++++
 gcc/cp/class.c                    | 16 +++++++++++++---
 gcc/testsuite/g++.dg/ext/align2.C | 14 ++++++++++++++
 3 files changed, 35 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/align2.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 7d70e13d2d53..44a4d901aa79 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2007-09-28  Jason Merrill  <jason@redhat.com>
+
+	PR c++/10179
+	* class.c (layout_empty_base): Take rli parameter, update
+	rli->record_align if empty base has user-specified alignment.
+	(build_base_field): Pass rli to it.
+
 2007-09-28  Paolo Carlini  <pcarlini@suse.de>
 
 	PR c++/33213
@@ -26,6 +33,7 @@
 
 2007-09-27  Jason Merrill  <jason@redhat.com>
 
+	PR c++/33571
 	* decl2.c (is_late_template_attribute): Don't crash on unknown
 	attribute.
 
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 5c3e0548044f..4419813b6b68 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -179,7 +179,7 @@ static void initialize_vtable (tree, tree);
 static void layout_nonempty_base_or_field (record_layout_info,
 					   tree, tree, splay_tree);
 static tree end_of_class (tree, int);
-static bool layout_empty_base (tree, tree, splay_tree);
+static bool layout_empty_base (record_layout_info, tree, tree, splay_tree);
 static void accumulate_vtbl_inits (tree, tree, tree, tree, tree);
 static tree dfs_accumulate_vtbl_inits (tree, tree, tree, tree,
 					       tree);
@@ -3517,7 +3517,8 @@ empty_base_at_nonzero_offset_p (tree type,
    type.  Return nonzero iff we added it at the end.  */
 
 static bool
-layout_empty_base (tree binfo, tree eoc, splay_tree offsets)
+layout_empty_base (record_layout_info rli, tree binfo,
+		   tree eoc, splay_tree offsets)
 {
   tree alignment;
   tree basetype = BINFO_TYPE (binfo);
@@ -3563,6 +3564,15 @@ layout_empty_base (tree binfo, tree eoc, splay_tree offsets)
 	  propagate_binfo_offsets (binfo, alignment);
 	}
     }
+
+  if (CLASSTYPE_USER_ALIGN (basetype))
+    {
+      rli->record_align = MAX (rli->record_align, CLASSTYPE_ALIGN (basetype));
+      if (warn_packed)
+	rli->unpacked_align = MAX (rli->unpacked_align, CLASSTYPE_ALIGN (basetype));
+      TYPE_USER_ALIGN (rli->t) = 1;
+    }
+
   return atend;
 }
 
@@ -3626,7 +3636,7 @@ build_base_field (record_layout_info rli, tree binfo,
 	 byte-aligned.  */
       eoc = round_up (rli_size_unit_so_far (rli),
 		      CLASSTYPE_ALIGN_UNIT (basetype));
-      atend = layout_empty_base (binfo, eoc, offsets);
+      atend = layout_empty_base (rli, binfo, eoc, offsets);
       /* A nearly-empty class "has no proper base class that is empty,
 	 not morally virtual, and at an offset other than zero."  */
       if (!BINFO_VIRTUAL_P (binfo) && CLASSTYPE_NEARLY_EMPTY_P (t))
diff --git a/gcc/testsuite/g++.dg/ext/align2.C b/gcc/testsuite/g++.dg/ext/align2.C
new file mode 100644
index 000000000000..da54bd9386b3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/align2.C
@@ -0,0 +1,14 @@
+// PR c++/10179
+
+struct __attribute((aligned(__alignof(double)))) A
+{ /* empty */ };
+
+struct T : public A
+{
+  char c;
+};
+
+template<bool> struct StaticAssert;
+template<> struct StaticAssert<true> {};
+
+StaticAssert<__alignof(T) == __alignof(double)> d;