[trans-mem, PATCH] do not dereference node if null in expand_call_tm (PR middle-end/52047)

[Patrick Marlier]

In the PR testcase, a call to __builtin_prefetch is done. When this 
function call comes into expand_call_tm, there is no cgraph_node 
associated for this builtin and thus node->local fails.

trans-mem.c (expand_call_tm):
      ...
      node = cgraph_get_node (fn_decl);
      if (node->local.tm_may_enter_irr)
        transaction_subcode_ior (region, GTMA_MAY_ENTER_IRREVOCABLE);
      ...
The attached patch adds a check for non-NULL node. I have added the 
testcase but I don't know if it is relevant.

Currently bootstrapping on i686-pc-linux-gnu. Tested on i686-pc-linux-gnu.

OK?

(I am almost sure I already proposed this modification few time ago but 
it have been lost somewhere.)
--
Patrick.

2012-01-31  Patrick Marlier  <patrick.marl...@gmail.com>

        PR middle-end/52047
        * trans-mem.c (expand_call_tm): Dereference node only if
        non-NULL.
Index: trans-mem.c
===================================================================
--- trans-mem.c (revision 183736)
+++ trans-mem.c (working copy)
@@ -1,5 +1,5 @@
 /* Passes for transactional memory support.
-   Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
 
    This file is part of GCC.
 
@@ -2267,7 +2267,7 @@ expand_call_tm (struct tm_region *region,
     }
 
   node = cgraph_get_node (fn_decl);
-  if (node->local.tm_may_enter_irr)
+  if (node && node->local.tm_may_enter_irr)
     transaction_subcode_ior (region, GTMA_MAY_ENTER_IRREVOCABLE);
 
   if (is_tm_abort (fn_decl))
Index: testsuite/gcc.dg/tm/pr52047.c
===================================================================
--- testsuite/gcc.dg/tm/pr52047.c       (revision 0)
+++ testsuite/gcc.dg/tm/pr52047.c       (revision 0)
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fgnu-tm -fprefetch-loop-arrays -w" } */
+
+int test2 (int x[])
+{
+  return x[12];
+}
+
+int test1 (void)
+{
+  int x[1000], i;
+  for (i = 0; i < 1000; i++)
+    x[i] = i;
+  return test2 (x);
+}
+
+int
+main ()
+{
+  __transaction_atomic
+  {
+    if (test1 ())
+      __transaction_cancel;
+  }
+  return 0;
+}