* cfgcleanup.c (try_forward_edges): Detect infinite loops while

        jump threading.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@48574 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7a4adfc..292a195 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,10 @@
 2002-01-05  Richard Henderson  <rth@redhat.com>
 
+       * cfgcleanup.c (try_forward_edges): Detect infinite loops while
+       jump threading.
+
+2002-01-05  Richard Henderson  <rth@redhat.com>
+
        * c-decl.c (c_expand_body): Don't call outlining_inline_function.
        * integrate.c (output_inline_function): Likewise.
        * toplev.c (rest_of_compilation): Do it here instead.  Move call

diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 96dee62..69045a0 100644 (file)
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -412,12 +412,32 @@ try_forward_edges (mode, b)
              edge t = thread_jump (mode, e, target);
              if (t)
                {
-                 new_target = t->dest;
-                 new_target_threaded = true;
                  if (!nthreaded_edges)
                    threaded_edges = xmalloc (sizeof (*threaded_edges)
                                              * n_basic_blocks);
+                 else
+                   {
+                     int i;
+
+                     /* Detect an infinite loop across blocks not
+                        including the start block.  */
+                     for (i = 0; i < nthreaded_edges; ++i)
+                       if (threaded_edges[i] == t)
+                         break;
+                     if (i < nthreaded_edges)
+                       break;
+                   }
+
+                 /* Detect an infinite loop across the start block.  */
+                 if (t->dest == b)
+                   break;
+
+                 if (nthreaded_edges >= n_basic_blocks)
+                   abort ();
                  threaded_edges[nthreaded_edges++] = t;
+
+                 new_target = t->dest;
+                 new_target_threaded = true;
                }
            }
 
@@ -504,7 +524,11 @@ try_forward_edges (mode, b)
              first->succ->count -= edge_count;
              first->frequency -= edge_frequency;
              if (first->succ->succ_next)
-               t = threaded_edges [n++];
+               {
+                 if (n >= nthreaded_edges)
+                   abort ();
+                 t = threaded_edges [n++];
+               }
              else
                t = first->succ;