PR tree-optimization/17549

[pf3gnuchains/gcc-fork.git] / gcc / tree-outof-ssa.c

diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c
index 65c74d3..c6aa812 100644 (file)
--- a/gcc/tree-outof-ssa.c
+++ b/gcc/tree-outof-ssa.c
@@ -1659,8 +1659,23 @@ find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
        {
          if (tab->version_info[SSA_NAME_VERSION (def)])
            {
        {
          if (tab->version_info[SSA_NAME_VERSION (def)])
            {

-             /* Mark expression as replaceable unless stmt is volatile.  */
-             if (!ann->has_volatile_ops)
+             bool same_root_var = false;
+             tree def2;
+             ssa_op_iter iter2;
+
+             /* See if the root variables are the same.  If they are, we
+                do not want to do the replacement to avoid problems with
+                code size, see PR tree-optimization/17549.  */
+             FOR_EACH_SSA_TREE_OPERAND (def2, stmt, iter2, SSA_OP_DEF)
+               if (SSA_NAME_VAR (def) == SSA_NAME_VAR (def2))
+                 {
+                   same_root_var = true;
+                   break;
+                 }
+
+             /* Mark expression as replaceable unless stmt is volatile
+                or DEF sets the same root variable as STMT.  */
+             if (!ann->has_volatile_ops && !same_root_var)

                mark_replaceable (tab, def);
              else
                finish_expr (tab, SSA_NAME_VERSION (def), false);
                mark_replaceable (tab, def);
              else
                finish_expr (tab, SSA_NAME_VERSION (def), false);