re PR tree-optimization/37879 (ICE with "wrong" use of noreturn attribute and optimization)

	PR tree-optimization/37879
	* predict.c (tree_estimate_probability): Check if last_stmt is
	non-NULL before dereferencing it.

	* gcc.dg/pr37879.c: New test.

From-SVN: r141390

gcc/ChangeLog

+2008-10-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/37879
+	* predict.c (tree_estimate_probability): Check if last_stmt is
+	non-NULL before dereferencing it.
+
 2008-10-27  Vladimir Makarov  <vmakarov@redhat.com>
 
 	* ira-int.h (ira_allocno): Add member updated_cover_class_cost.

gcc/predict.c

@@ -1599,6 +1599,7 @@ tree_estimate_probability (void)
     {
       edge e;
       edge_iterator ei;
+      gimple last;
 
       FOR_EACH_EDGE (e, ei, bb->succs)
 	{
@@ -1621,7 +1622,8 @@ tree_estimate_probability (void)
 	      && e->dest != EXIT_BLOCK_PTR
 	      && single_succ_p (e->dest)
 	      && single_succ_edge (e->dest)->dest == EXIT_BLOCK_PTR
-	      && gimple_code (last_stmt (e->dest)) == GIMPLE_RETURN)
+	      && (last = last_stmt (e->dest)) != NULL
+	      && gimple_code (last) == GIMPLE_RETURN)
 	    {
 	      edge e1;
 	      edge_iterator ei1;

gcc/testsuite/ChangeLog

+2008-10-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/37879
+	* gcc.dg/pr37879.c: New test.
+
 2008-10-24  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	PR target/37841

gcc/testsuite/gcc.dg/pr37879.c

+/* PR tree-optimization/37879 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+static inline void bar (int) __attribute__ ((noreturn));
+void baz () __attribute__ ((noreturn));
+
+inline int
+foo (int i)
+{
+  return i;
+}
+
+int i = 23;
+static inline void
+bar (int j)
+{
+  if (j)
+    asm ("");
+}		/* { dg-warning "does return" } */
+
+void
+baz ()
+{
+  int j;
+  bar (foo (j = i++));
+  asm ("");
+}