re PR tree-optimization/49618 (When building uClibc with GCC 4.6.1 old_atexit is miscompiled)

	PR tree-optimization/49618
	* tree-eh.c (tree_could_trap_p) <case CALL_EXPR>: For DECL_WEAK
	t recurse on the decl.
	<case FUNCTION_DECL, case VAR_DECL>: For DECL_WEAK decls
	return true if expr isn't known to be defined in current
	TU or some other LTO partition.

From-SVN: r175884

gcc/ChangeLog

+2011-07-05  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/49618
+	* tree-eh.c (tree_could_trap_p) <case CALL_EXPR>: For DECL_WEAK
+	t recurse on the decl.
+	<case FUNCTION_DECL, case VAR_DECL>: For DECL_WEAK decls
+	return true if expr isn't known to be defined in current
+	TU or some other LTO partition.
+
 2011-07-05  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	* params.def (PARAM_CASE_VALUES_THRESHOLD): New parameter to

gcc/tree-eh.c

@@ -2449,8 +2449,42 @@ tree_could_trap_p (tree expr)
     case CALL_EXPR:
       t = get_callee_fndecl (expr);
       /* Assume that calls to weak functions may trap.  */
-      if (!t || !DECL_P (t) || DECL_WEAK (t))
+      if (!t || !DECL_P (t))
 	return true;
+      if (DECL_WEAK (t))
+	return tree_could_trap_p (t);
+      return false;
+
+    case FUNCTION_DECL:
+      /* Assume that accesses to weak functions may trap, unless we know
+	 they are certainly defined in current TU or in some other
+	 LTO partition.  */
+      if (DECL_WEAK (expr))
+	{
+	  struct cgraph_node *node;
+	  if (!DECL_EXTERNAL (expr))
+	    return false;
+	  node = cgraph_function_node (cgraph_get_node (expr), NULL);
+	  if (node && node->in_other_partition)
+	    return false;
+	  return true;
+	}
+      return false;
+
+    case VAR_DECL:
+      /* Assume that accesses to weak vars may trap, unless we know
+	 they are certainly defined in current TU or in some other
+	 LTO partition.  */
+      if (DECL_WEAK (expr))
+	{
+	  struct varpool_node *node;
+	  if (!DECL_EXTERNAL (expr))
+	    return false;
+	  node = varpool_variable_node (varpool_get_node (expr), NULL);
+	  if (node && node->in_other_partition)
+	    return false;
+	  return true;
+	}
       return false;
 
     default: