[compiler] Drop the CompareNilIC.

src/crankshaft/hydrogen-instructions.cc

Index: src/crankshaft/hydrogen-instructions.cc
diff --git a/src/crankshaft/hydrogen-instructions.cc b/src/crankshaft/hydrogen-instructions.cc
index a9c6228cd35c096636a22d9e2358434dfd48e5cc..9277bcfa7880bc70cabd772371f68c63b979100a 100644
--- a/src/crankshaft/hydrogen-instructions.cc
+++ b/src/crankshaft/hydrogen-instructions.cc
@@ -3267,11 +3267,26 @@ bool HIsStringAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
 
 
 bool HIsUndetectableAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
+  if (known_successor_index() != kNoKnownSuccessorIndex) {
+    *block = SuccessorAt(known_successor_index());
+    return true;
+  }
   if (FLAG_fold_constants && value()->IsConstant()) {
     *block = HConstant::cast(value())->IsUndetectable()
         ? FirstSuccessor() : SecondSuccessor();
     return true;
   }
+  if (value()->type().IsNull() || value()->type().IsUndefined()) {
+    *block = FirstSuccessor();
+    return true;
+  }
+  if (value()->type().IsBoolean() ||
+      value()->type().IsSmi() ||
+      value()->type().IsString() ||
+      value()->type().IsJSReceiver()) {
+    *block = SecondSuccessor();
+    return true;
+  }
   *block = NULL;
   return false;
 }