Only generate a single normal IC per kind per slow-mode map.

src/x64/stub-cache-x64.cc

Index: src/x64/stub-cache-x64.cc
diff --git a/src/x64/stub-cache-x64.cc b/src/x64/stub-cache-x64.cc
index 93173f162bd3a4811ca0a8e3bc34950034077732..c2638942d7f9d65e679bc1191acfd270149c74dc 100644
--- a/src/x64/stub-cache-x64.cc
+++ b/src/x64/stub-cache-x64.cc
@@ -1234,8 +1234,14 @@ Handle<Code> PropertyICCompiler::CompilePolymorphic(TypeHandleList* types,
 
   if (check == PROPERTY &&
       (kind() == Code::KEYED_LOAD_IC || kind() == Code::KEYED_STORE_IC)) {
-    __ Cmp(this->name(), name);
-    __ j(not_equal, &miss);
+    // In case we are compiling an IC for dictionary loads and stores, just
+    // check whether the name is unique.
+    if (name.is_identical_to(isolate()->factory()->normal_ic_symbol())) {
+      __ JumpIfNotUniqueName(this->name(), &miss);
+    } else {
+      __ Cmp(this->name(), name);
+      __ j(not_equal, &miss);
+    }
   }
 
   Label number_case;