Merge (x & y) == 0 pattern to emit a single test instruction.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 1b004138c83945117f66436c0aa1cbd9a7447255..5220543e73aeb741fe2ed03612bf9613c6cbbf0b 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -504,6 +504,7 @@ class EmbeddedArray<T, 0> {
   M(InvokeMathCFunction)                                                       \
   M(GuardField)                                                                \
   M(IfThenElse)                                                                \
+  M(TestSmi)                                                                   \
 
 #define FORWARD_DECLARATION(type) class type##Instr;
 FOR_EACH_INSTRUCTION(FORWARD_DECLARATION)
@@ -2486,6 +2487,10 @@ class ComparisonInstr : public TemplateDefinition<2> {
     deopt_id_ = deopt_id;
   }
 
+  virtual bool IsSmiEquality() const {
+    return false;
+  }
+
  protected:
   Token::Kind kind_;
 };
@@ -2585,6 +2590,40 @@ class StrictCompareInstr : public ComparisonInstr {
 };
 
 
+// Comparison instruction that is equivalent to the (left & right) == 0
+// comparison pattern.
+class TestSmiInstr : public ComparisonInstr {
+ public:
+  TestSmiInstr(Token::Kind kind, Value* left, Value* right)
+      : ComparisonInstr(kind, left, right) {
+  }
+
+  DECLARE_INSTRUCTION(TestSmi);
+
+  virtual CompileType ComputeType() const {
+    return CompileType::Bool();
+  }
+
+  virtual bool CanDeoptimize() const {
+    return false;
+  }
+
+  virtual bool HasSideEffect() const {
+    return false;
+  }
+
+  virtual void EmitBranchCode(FlowGraphCompiler* compiler,
+                              BranchInstr* branch);
+
+  virtual Representation RequiredInputRepresentation(intptr_t idx) const {
+    return kTagged;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestSmiInstr);
+};
+
+
 class EqualityCompareInstr : public ComparisonInstr {
  public:
   EqualityCompareInstr(intptr_t token_pos,
@@ -2647,6 +2686,10 @@ class EqualityCompareInstr : public ComparisonInstr {
 
   bool IsPolymorphic() const;
 
+  virtual bool IsSmiEquality() const {
+    return receiver_class_id() == kSmiCid;
+  }
+
  private:
   const ICData* ic_data_;
   const intptr_t token_pos_;