2010-11-11  Jakub Jelinek  <jakub@redhat.com>

	Backport from mainline
	2010-11-03  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/46165
	* tree-ssa-pre.c (eliminate): Return TODO_cleanup_cfg if changing
	a normal call into noreturn call.

	* gcc.dg/pr46165.c: New test.

--- gcc/tree-ssa-pre.c	(revision 166235)
+++ gcc/tree-ssa-pre.c	(revision 166236)
@@ -4311,6 +4311,8 @@ eliminate (void)
 	      && TREE_CODE (gimple_call_fn (stmt)) == SSA_NAME)
 	    {
 	      tree fn = VN_INFO (gimple_call_fn (stmt))->valnum;
+	      bool was_noreturn = gimple_call_noreturn_p (stmt);
+ 
 	      if (TREE_CODE (fn) == ADDR_EXPR
 		  && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL)
 		{
@@ -4324,6 +4326,12 @@ eliminate (void)
 
 		  gimple_call_set_fn (stmt, fn);
 		  update_stmt (stmt);
+
+		  /* When changing a call into a noreturn call, cfg cleanup
+		     is needed to fix up the noreturn call.  */
+		  if (!was_noreturn && gimple_call_noreturn_p (stmt))
+		    todo |= TODO_cleanup_cfg;
+
 		  if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
 		    {
 		      bitmap_set_bit (need_eh_cleanup,
--- gcc/testsuite/gcc.dg/pr46165.c	(revision 0)
+++ gcc/testsuite/gcc.dg/pr46165.c	(revision 166236)
@@ -0,0 +1,11 @@
+/* PR tree-optimization/46165 */
+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-ccp -fno-tree-copy-prop -fno-tree-dce" } */
+
+extern void foo (void) __attribute__((noreturn));
+void
+g (void)
+{
+  void (*f) (void) = foo;
+  f ();
+}