Re: [PATCH] Improve DOM's optimization of control statements

	* tree-ssa-dom.c (optimize_stmt): Note when loop structures need
	fixups.

From-SVN: r228415

gcc/ChangeLog

+2015-10-02  Jeff Law  <law@redhat.com>
+
+	* tree-ssa-dom.c (optimize_stmt): Note when loop structures need
+	fixups.
+
 2015-10-02  Thomas Schwinge  <thomas@codesourcery.com>
 
 	PR target/67822

gcc/tree-ssa-dom.c

@@ -1843,6 +1843,12 @@ optimize_stmt (basic_block bb, gimple_stmt_iterator si,
 	      /* Delete threads that start at BB.  */
 	      remove_jump_threads_starting_at (bb);
 
+	      /* If BB is in a loop, then removing an outgoing edge from BB
+		 may cause BB to move outside the loop, changes in the
+		 loop exit edges, etc.  So note that loops need fixing.  */
+	      if (bb_loop_depth (bb) > 0)
+		loops_state_set (LOOPS_NEED_FIXUP);
+
 	      /* Now clean up the control statement at the end of
 		 BB and remove unexecutable edges.  */
 	      remove_ctrl_stmt_and_useless_edges (bb, taken_edge->dest);