2011-08-18 Tobias Burnus <burnus@net-b.de>

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

diff --git a/gcc/tree-ssa-propagate.c b/gcc/tree-ssa-propagate.c
index e08d2e7..7741db8 100644 (file)
--- a/gcc/tree-ssa-propagate.c
+++ b/gcc/tree-ssa-propagate.c
@@ -601,19 +601,6 @@ valid_gimple_rhs_p (tree expr)
           }
           break;
 
-       case TRUTH_NOT_EXPR:
-         if (!is_gimple_val (TREE_OPERAND (expr, 0)))
-           return false;
-         break;
-
-       case TRUTH_AND_EXPR:
-       case TRUTH_XOR_EXPR:
-       case TRUTH_OR_EXPR:
-         if (!is_gimple_val (TREE_OPERAND (expr, 0))
-             || !is_gimple_val (TREE_OPERAND (expr, 1)))
-           return false;
-         break;
-
        default:
          return false;
        }
@@ -760,8 +747,11 @@ update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
           /* No value is expected, and EXPR has no effect.
              Replace it with an empty statement.  */
           new_stmt = gimple_build_nop ();
-         unlink_stmt_vdef (stmt);
-         release_defs (stmt);
+         if (gimple_in_ssa_p (cfun))
+           {
+             unlink_stmt_vdef (stmt);
+             release_defs (stmt);
+           }
         }
       else
         {
@@ -773,7 +763,8 @@ update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
           lhs = create_tmp_var (TREE_TYPE (expr), NULL);
           new_stmt = gimple_build_assign (lhs, expr);
           add_referenced_var (lhs);
-          lhs = make_ssa_name (lhs, new_stmt);
+         if (gimple_in_ssa_p (cfun))
+           lhs = make_ssa_name (lhs, new_stmt);
           gimple_assign_set_lhs (new_stmt, lhs);
          gimple_set_vuse (new_stmt, gimple_vuse (stmt));
          gimple_set_vdef (new_stmt, gimple_vdef (stmt));
@@ -975,6 +966,9 @@ replace_phi_args_in (gimple phi, ssa_prop_get_value_fn get_value)
 
    DO_DCE is true if trivially dead stmts can be removed.
 
+   If DO_DCE is true, the statements within a BB are walked from
+   last to first element.  Otherwise we scan from first to last element.
+
    Return TRUE when something changed.  */
 
 bool
@@ -1055,9 +1049,10 @@ substitute_and_fold (ssa_prop_get_value_fn get_value_fn,
        for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i))
          replace_phi_args_in (gsi_stmt (i), get_value_fn);
 
-      /* Propagate known values into stmts.  Do a backward walk to expose
-        more trivially deletable stmts.  */
-      for (i = gsi_last_bb (bb); !gsi_end_p (i);)
+      /* Propagate known values into stmts.  Do a backward walk if
+         do_dce is true. In some case it exposes
+        more trivially deletable stmts to walk backward.  */
+      for (i = (do_dce ? gsi_last_bb (bb) : gsi_start_bb (bb)); !gsi_end_p (i);)
        {
           bool did_replace;
          gimple stmt = gsi_stmt (i);
@@ -1066,7 +1061,10 @@ substitute_and_fold (ssa_prop_get_value_fn get_value_fn,
          gimple_stmt_iterator oldi;
 
          oldi = i;
-         gsi_prev (&i);
+         if (do_dce)
+           gsi_prev (&i);
+         else
+           gsi_next (&i);
 
          /* Ignore ASSERT_EXPRs.  They are used by VRP to generate
             range information for names and they are discarded
@@ -1122,12 +1120,12 @@ substitute_and_fold (ssa_prop_get_value_fn get_value_fn,
            {
              did_replace = true;
              prop_stats.num_stmts_folded++;
+             stmt = gsi_stmt (oldi);
+             update_stmt (stmt);
            }
 
-         /* Only replace real uses if we couldn't fold the
-            statement using value range information.  */
-         if (get_value_fn
-             && !did_replace)
+         /* Replace real uses in the statement.  */
+         if (get_value_fn)
            did_replace |= replace_uses_in (stmt, get_value_fn);
 
          /* If we made a replacement, fold the statement.  */