[PATCH] Fix PR54811

[Richard Guenther]

This fixes PR54811 for me - still Ada LTO bootstrap fails for me
with cgraph verification ICEs.

LTO bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2012-10-05  Richard Guenther  <rguent...@suse.de>

        PR middle-end/54811
        * tree-ssa-live.c (clear_unused_block_pointer_1): Look at
        DECL_DEBUG_EXPR again.

Index: gcc/tree-ssa-live.c
===================================================================
--- gcc/tree-ssa-live.c (revision 192114)
+++ gcc/tree-ssa-live.c (working copy)
@@ -621,6 +621,11 @@ clear_unused_block_pointer_1 (tree *tp,
   if (EXPR_P (*tp) && TREE_BLOCK (*tp)
       && !TREE_USED (TREE_BLOCK (*tp)))
     TREE_SET_BLOCK (*tp, NULL);
+  if (TREE_CODE (*tp) == VAR_DECL && DECL_DEBUG_EXPR_IS_FROM (*tp))
+    {
+      tree debug_expr = DECL_DEBUG_EXPR (*tp);
+      walk_tree (&debug_expr, clear_unused_block_pointer_1, NULL, NULL);
+    }
   return NULL_TREE;
 }