Index: gcc-head/gcc/tree-ssa-math-opts.c
===================================================================
--- gcc-head.orig/gcc/tree-ssa-math-opts.c
+++ gcc-head/gcc/tree-ssa-math-opts.c
@@ -1820,8 +1820,10 @@ execute_optimize_bswap (void)
   FOR_EACH_BB (bb)
     {
       gimple_stmt_iterator gsi;
-
+/*
       for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+ */
+      for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
         {
          gimple stmt = gsi_stmt (gsi);
          tree bswap_src, bswap_type;