re PR tree-optimization/21610 (ICE in make_decl_rtl)

	PR tree-optimization/21610
	* c-typeck.c (decl_constant_value_for_broken_optimization): If not
	returning DECL, call unshare_expr.

	* gcc.c-torture/compile/20050516-1.c: New test.

From-SVN: r99815

gcc/ChangeLog

+2005-05-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/21610
+	* c-typeck.c (decl_constant_value_for_broken_optimization): If not
+	returning DECL, call unshare_expr.
+
 2005-05-17  Hans-Peter Nilsson  <hp@axis.com>
 
 	* config/cris/cris.md: Unquote preparation and output statements.

gcc/c-typeck.c

@@ -1249,10 +1249,18 @@ decl_constant_value (tree decl)
 static tree
 decl_constant_value_for_broken_optimization (tree decl)
 {
+  tree ret;
+
   if (pedantic || DECL_MODE (decl) == BLKmode)
     return decl;
-  else
-    return decl_constant_value (decl);
+
+  ret = decl_constant_value (decl);
+  /* Avoid unwanted tree sharing between the initializer and current
+     function's body where the tree can be modified e.g. by the
+     gimplifier.  */
+  if (ret != decl && TREE_STATIC (decl))
+    ret = unshare_expr (ret);
+  return ret;
 }
 
 

gcc/testsuite/ChangeLog

 2005-05-17  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/21610
+	* gcc.c-torture/compile/20050516-1.c: New test.
+
 	PR fortran/15080
 	* gfortran.fortran-torture/execute/forall_3.f90: Remove comment
 	about the test failing.

gcc/testsuite/gcc.c-torture/compile/20050516-1.c

+/* PR tree-optimization/21610 */
+
+struct S { char s; };
+struct T { struct S t; };
+
+struct S *const p = &((struct T * const) (0x4000))->t;
+
+void
+foo (void)
+{
+  p->s = 0;
+}