Use empty() instead of comparing size() with zero.

llvm-svn: 46514
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 4e835b8..5a1bf93 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -801,7 +801,7 @@
 
   // If we've change things around then replace token factor.
   if (Changed) {
-    if (Ops.size() == 0) {
+    if (Ops.empty()) {
       // The entry token is the only possible outcome.
       Result = DAG.getEntryNode();
     } else {