PR c/24255

        * c-typeck.c (convert_for_assignment): Use build_constructor_single
        to initialize a transparent union instead of a nop_expr.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@105270 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 88834b6..9d7fc4e 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2005-10-11  Richard Henderson  <rth@redhat.com>
 
+       PR c/24255
+       * c-typeck.c (convert_for_assignment): Use build_constructor_single
+       to initialize a transparent union instead of a nop_expr.
+
+2005-10-11  Richard Henderson  <rth@redhat.com>
+
        * Makefile.in (tree-ssa-dce.o): Depend on SCEV_H.
        * tree-ssa-dce.c: Include tree-scalar-evolution.h.
        (tree_ssa_dce_loop): Call scev_reset.

diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 8a90476..cf9798a 100644 (file)
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -3799,13 +3799,11 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
   else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type)
           && (errtype == ic_argpass || errtype == ic_argpass_nonproto))
     {
-      tree memb_types;
-      tree marginal_memb_type = 0;
+      tree memb, marginal_memb = NULL_TREE;
 
-      for (memb_types = TYPE_FIELDS (type); memb_types;
-          memb_types = TREE_CHAIN (memb_types))
+      for (memb = TYPE_FIELDS (type); memb ; memb = TREE_CHAIN (memb))
        {
-         tree memb_type = TREE_TYPE (memb_types);
+         tree memb_type = TREE_TYPE (memb);
 
          if (comptypes (TYPE_MAIN_VARIANT (memb_type),
                         TYPE_MAIN_VARIANT (rhstype)))
@@ -3837,8 +3835,8 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
                    break;
 
                  /* Keep looking for a better type, but remember this one.  */
-                 if (!marginal_memb_type)
-                   marginal_memb_type = memb_type;
+                 if (!marginal_memb)
+                   marginal_memb = memb;
                }
            }
 
@@ -3852,13 +3850,13 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
            }
        }
 
-      if (memb_types || marginal_memb_type)
+      if (memb || marginal_memb)
        {
-         if (!memb_types)
+         if (!memb)
            {
              /* We have only a marginally acceptable member type;
                 it needs a warning.  */
-             tree ttl = TREE_TYPE (marginal_memb_type);
+             tree ttl = TREE_TYPE (TREE_TYPE (marginal_memb));
              tree ttr = TREE_TYPE (rhstype);
 
              /* Const and volatile mean something different for function
@@ -3893,12 +3891,14 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
                                        "from pointer target type"),
                                     G_("return discards qualifiers from "
                                        "pointer target type"));
+
+             memb = marginal_memb;
            }
 
          if (pedantic && (!fundecl || !DECL_IN_SYSTEM_HEADER (fundecl)))
            pedwarn ("ISO C prohibits argument conversion to union type");
 
-         return build1 (NOP_EXPR, type, rhs);
+         return build_constructor_single (type, memb, rhs);
        }
     }
 

diff --git a/gcc/testsuite/gcc.dg/transparent-union-5.c b/gcc/testsuite/gcc.dg/transparent-union-5.c
new file mode 100644 (file)
index 0000000..47e245e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/transparent-union-5.c
@@ -0,0 +1,37 @@
+/* PR 24255 */
+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+extern void abort (void);
+
+union wait { int w_status; };
+
+typedef union
+{
+  union wait *uptr;
+  int *iptr;
+} WAIT_STATUS __attribute__ ((__transparent_union__));
+
+int status;
+union wait wstatus;
+
+void __attribute__((noinline))
+test1 (WAIT_STATUS s)
+{
+  if (s.iptr != &status)
+    abort ();
+}
+
+void __attribute__((noinline))
+test2 (WAIT_STATUS s)
+{
+  if (s.uptr != &wstatus)
+    abort ();
+}
+
+int main()
+{
+  test1 (&status);
+  test2 (&wstatus);
+  return 0;
+}