PR rtl-optimization/32773

	* cfglayout.c (force_one_exit_fallthru): New function.
	(cfg_layout_finalize): Use it.

	* gcc.dg/pr32773.c: New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@126700 138bc75d-0d04-0410-961f-82ee72b054a4

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2007-07-17  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR rtl-optimization/32773
+	* cfglayout.c (force_one_exit_fallthru): New function.
+	(cfg_layout_finalize): Use it.
+
 2007-07-16  Richard Guenther  <rguenther@suse.de>
 	    Uros Bizjak  <ubizjak@gmail.com>
 

gcc/cfglayout.c

@@ -963,6 +963,56 @@ fixup_fallthru_exit_predecessor (void)
       bb->aux = NULL;
     }
 }
+
+/* In case there are more than one fallthru predecessors of exit, force that
+   there is only one.  */
+
+static void
+force_one_exit_fallthru (void)
+{
+  edge e, predecessor = NULL;
+  bool more = false;
+  edge_iterator ei;
+  basic_block forwarder, bb;
+
+  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+    if (e->flags & EDGE_FALLTHRU)
+      {
+	if (predecessor == NULL)
+	  predecessor = e;
+	else
+	  {
+	    more = true;
+	    break;
+	  }
+      }
+
+  if (!more)
+    return;
+
+  /* Exit has several fallthru predecessors.  Create a forwarder block for
+     them.  */
+  forwarder = split_edge (predecessor);
+  for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
+    {
+      if (e->src == forwarder
+	  || !(e->flags & EDGE_FALLTHRU))
+	ei_next (&ei);
+      else
+	redirect_edge_and_branch_force (e, forwarder);
+    }
+
+  /* Fix up the chain of blocks -- make FORWARDER immediately preceed the
+     exit block.  */
+  FOR_EACH_BB (bb)
+    {
+      if (bb->aux == NULL && bb != forwarder)
+	{
+	  bb->aux = forwarder;
+	  break;
+	}
+    }
+}
 
 /* Return true in case it is possible to duplicate the basic block BB.  */
 
@@ -1178,6 +1228,7 @@ cfg_layout_finalize (void)
 #ifdef ENABLE_CHECKING
   verify_flow_info ();
 #endif
+  force_one_exit_fallthru ();
   rtl_register_cfg_hooks ();
   if (reload_completed
 #ifdef HAVE_epilogue

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2007-07-17  Zdenek Dvorak  <dvorakz@suse.cz>
+
+	PR rtl-optimization/32773
+	* gcc.dg/pr32773.c: New test.
+
 2007-07-16  Andrew Pinski  <andrew_pinski@playstation.sony.com>
 
 	* gcc.target/spu/intrinsics-1.c: Use dg-message to

gcc/testsuite/gcc.dg/pr32773.c

@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fprofile-use" } */
+/* { dg-options "-O -m4 -fprofile-use" { target sh-*-* } } */
+
+void foo (int *p)
+{
+  if (p)
+    *p = 0;
+} /* { dg-message "note: \[^\n\]*execution counts estimated" } */
+
+/* { dg-final { cleanup-coverage-files } } */