2010-12-06 Jerry DeLisle <jvdelisle@gcc.gnu.org>

[pf3gnuchains/gcc-fork.git] / gcc / tree-if-conv.c

diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 17b6672..fc65845 100644 (file)
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -1224,7 +1224,7 @@ predicate_scalar_phi (gimple phi, tree cond,
 {
   gimple new_stmt;
   basic_block bb;
-  tree rhs, res, arg;
+  tree rhs, res, arg, scev;
 
   gcc_assert (gimple_code (phi) == GIMPLE_PHI
              && gimple_phi_num_args (phi) == 2);
@@ -1236,8 +1236,12 @@ predicate_scalar_phi (gimple phi, tree cond,
 
   bb = gimple_bb (phi);
 
-  arg = degenerate_phi_result (phi);
-  if (arg)
+  if ((arg = degenerate_phi_result (phi))
+      || ((scev = analyze_scalar_evolution (gimple_bb (phi)->loop_father,
+                                           res))
+         && !chrec_contains_undetermined (scev)
+         && scev != res
+         && (arg = gimple_phi_arg_def (phi, 0))))
     rhs = arg;
   else
     {