dce.c (fini_dce): Call df_analyze again just in case delete_unmarked_insns removed anything.

       * dce.c (fini_dce): Call df_analyze again just in case
       delete_unmarked_insns removed anything.

From-SVN: r201886

gcc/ChangeLog

+2013-08-20  Alexey Makhalov  <makhaloff@gmail.com>
+
+	* dce.c (fini_dce): Call df_analyze again just in case
+	delete_unmarked_insns removed anything.
+
 2013-08-20  Teresa Johnson  <tejohnson@google.com>
 
 	PR rtl-optimizations/57451

gcc/dce.c

@@ -745,6 +745,17 @@ fini_dce (bool fast)
       bitmap_obstack_release (&dce_blocks_bitmap_obstack);
       bitmap_obstack_release (&dce_tmp_bitmap_obstack);
     }
+
+  /* If DCE removes the last reference to a hard register, we want
+     to recompute REGS_EVER_LIVE and the global life information.
+
+     Ideally we'd look at REGS_EVER_LIVE before and after and only
+     rerun DF analysis if something changed.  */
+  if (!df_in_progress)
+    {
+      df_compute_regs_ever_live (true);
+      df_analyze ();
+    }
 }