[Bug bootstrap/60984] [4.9 Regression] AIX: gcc-4.9.0 bootstrap fails in stage-2

["hubicka at ucw dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60984

--- Comment #24 from Jan Hubicka <hubicka at ucw dot cz> ---
Hi,
the problem turns out to be quite ugly issue where inline_call removes dead
alias, but the alias is being walked by cgraph_for_node_and_aliases used
by ipa-inline to inline function into all callees.
The attached patch (I am still testing) makes us to restart the walk in this
case.

Honza

Index: ipa-inline-transform.c
===================================================================
--- ipa-inline-transform.c    (revision 210624)
+++ ipa-inline-transform.c    (working copy)
@@ -214,6 +214,7 @@
    it is NULL. If UPDATE_OVERALL_SUMMARY is false, do not bother to recompute
overall
    size of caller after inlining. Caller is required to eventually do it via
    inline_update_overall_summary.
+   If callee_removed is non-NULL, set it to true if we removed callee node.

    Return true iff any new callgraph edges were discovered as a
    result of inlining.  */
@@ -221,7 +222,8 @@
 bool
 inline_call (struct cgraph_edge *e, bool update_original,
          vec<cgraph_edge_p> *new_edges,
-         int *overall_size, bool update_overall_summary)
+         int *overall_size, bool update_overall_summary,
+         bool *callee_removed)
 {
   int old_size = 0, new_size = 0;
   struct cgraph_node *to = NULL;
@@ -260,6 +262,8 @@
         {
           next_alias = cgraph_alias_target (alias);
           cgraph_remove_node (alias);
+          if (callee_removed)
+        *callee_removed = true;
           alias = next_alias;
         }
       else
Index: ipa-inline.c
===================================================================
--- ipa-inline.c    (revision 210624)
+++ ipa-inline.c    (working copy)
@@ -1971,6 +1971,8 @@
 inline_to_all_callers (struct cgraph_node *node, void *data)
 {
   int *num_calls = (int *)data;
+  bool callee_removed = false;
+
   while (node->callers && !node->global.inlined_to)
     {
       struct cgraph_node *caller = node->callers->caller;
@@ -1987,7 +1989,7 @@
            inline_summary (node->callers->caller)->size);
     }

-      inline_call (node->callers, true, NULL, NULL, true);
+      inline_call (node->callers, true, NULL, NULL, true, &callee_removed);
       if (dump_file)
     fprintf (dump_file,
          " Inlined into %s which now has %i size\n",
@@ -1997,8 +1999,10 @@
     {
       if (dump_file)
         fprintf (dump_file, "New calls found; giving up.\n");
-      return true;
+      return callee_removed;
     }
+      if (callee_removed)
+    return true;
     }
   return false;
 }
@@ -2244,8 +2248,9 @@
           int num_calls = 0;
           cgraph_for_node_and_aliases (node, sum_callers,
                        &num_calls, true);
-          cgraph_for_node_and_aliases (node, inline_to_all_callers,
-                       &num_calls, true);
+          while (cgraph_for_node_and_aliases (node, inline_to_all_callers,
+                              &num_calls, true))
+        ;
           remove_functions = true;
         }
     }
Index: ipa-inline.h
===================================================================
--- ipa-inline.h    (revision 210624)
+++ ipa-inline.h    (working copy)
@@ -236,7 +236,8 @@
 bool speculation_useful_p (struct cgraph_edge *e, bool anticipate_inlining);

 /* In ipa-inline-transform.c  */
-bool inline_call (struct cgraph_edge *, bool, vec<cgraph_edge_p> *, int *,
bool);
+bool inline_call (struct cgraph_edge *, bool, vec<cgraph_edge_p> *, int *,
bool,
+          bool *callee_removed = NULL);
 unsigned int inline_transform (struct cgraph_node *);
 void clone_inlined_nodes (struct cgraph_edge *e, bool, bool, int *,
               int freq_scale);