Let NaN flow as double into HBranch

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index f4a92a5316d3bca8a58df6fff3e39de8c96486d0..5ed046841a4fdeb05e564eeec63b8bb9e7c1fc4b 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1276,20 +1276,26 @@ void HReturn::PrintDataTo(StringStream* stream) {
 
 Representation HBranch::observed_input_representation(int index) {
   static const ToBooleanStub::Types tagged_types(
-      ToBooleanStub::UNDEFINED |
       ToBooleanStub::NULL_TYPE |
       ToBooleanStub::SPEC_OBJECT |
       ToBooleanStub::STRING |
       ToBooleanStub::SYMBOL);
   if (expected_input_types_.ContainsAnyOf(tagged_types)) {
     return Representation::Tagged();
-  } else if (expected_input_types_.Contains(ToBooleanStub::HEAP_NUMBER)) {
+  }
+  if (expected_input_types_.Contains(ToBooleanStub::UNDEFINED)) {
+    if (expected_input_types_.Contains(ToBooleanStub::HEAP_NUMBER)) {
+      return Representation::Double();
+    }
+    return Representation::Tagged();
+  }
+  if (expected_input_types_.Contains(ToBooleanStub::HEAP_NUMBER)) {
     return Representation::Double();
-  } else if (expected_input_types_.Contains(ToBooleanStub::SMI)) {
+  }
+  if (expected_input_types_.Contains(ToBooleanStub::SMI)) {
     return Representation::Smi();
-  } else {
-    return Representation::None();
   }
+  return Representation::None();
 }