PR c/70297

	* c-decl.c (merge_decls): Also set TYPE_ALIGN and TYPE_USER_ALIGN.

	* decl.c (duplicate_decls): Also set TYPE_ALIGN and TYPE_USER_ALIGN.

	* c-c++-common/pr70297.c: New test.
	* g++.dg/cpp0x/typedef-redecl.C: New test.
	* gcc.dg/typedef-redecl2.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@234626 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 29 insertions, 0 deletions

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index bab47153235..0dd2121b868 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -2358,6 +2358,35 @@ merge_decls (tree newdecl, tree olddecl, tree newtype, tree oldtype)
   DECL_ATTRIBUTES (newdecl)
     = targetm.merge_decl_attributes (olddecl, newdecl);
 
+  /* For typedefs use the old type, as the new type's DECL_NAME points
+     at newdecl, which will be ggc_freed.  */
+  if (TREE_CODE (newdecl) == TYPE_DECL)
+    {
+      /* But NEWTYPE might have an attribute, honor that.  */
+      tree tem = newtype;
+      newtype = oldtype;
+
+      if (TYPE_USER_ALIGN (tem))
+	{
+	  if (TYPE_ALIGN (tem) > TYPE_ALIGN (newtype))
+	    TYPE_ALIGN (newtype) = TYPE_ALIGN (tem);
+	  TYPE_USER_ALIGN (newtype) = true;
+	}
+
+      /* And remove the new type from the variants list.  */
+      if (TYPE_NAME (TREE_TYPE (newdecl)) == newdecl)
+	{
+	  tree remove = TREE_TYPE (newdecl);
+	  for (tree t = TYPE_MAIN_VARIANT (remove); ;
+	       t = TYPE_NEXT_VARIANT (t))
+	    if (TYPE_NEXT_VARIANT (t) == remove)
+	      {
+		TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (remove);
+		break;
+	      }
+	}
+    }
+
   /* Merge the data types specified in the two decls.  */
   TREE_TYPE (newdecl)
     = TREE_TYPE (olddecl)