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

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
===================================================================
--- runtime/vm/intermediate_language.h	(revision 29901)
+++ runtime/vm/intermediate_language.h	(working copy)
@@ -697,6 +697,7 @@
   M(Int32x4SetFlag)                                                           \
   M(Int32x4ToFloat32x4)                                                       \
   M(BinaryInt32x4Op)                                                          \
+  M(TestSmi)

[zra, 2013/11/05 18:38:03]

It looks like we usually put a trailing \ after the last line of a macro.

[Florian Schneider, 2013/11/06 12:13:42]

Done.

 
 
 #define FORWARD_DECLARATION(type) class type##Instr;
@@ -2985,6 +2986,45 @@
 };
 
 
+// Comparison instruction that is equivalent to the (left & right) == 0
+// comparison pattern.
+class TestSmiInstr : public ComparisonInstr {
+ public:
+  TestSmiInstr(intptr_t token_pos, Token::Kind kind, Value* left, Value* right)
+      : ComparisonInstr(token_pos, kind, left, right) {
+    ASSERT(kind == Token::kEQ || kind == Token::kNE);
+  }
+
+  DECLARE_INSTRUCTION(TestSmi);
+  virtual CompileType ComputeType() const;
+
+  virtual bool CanDeoptimize() const { return false; }
+
+  virtual bool CanBecomeDeoptimizationTarget() const {
+    // TestSmi can be merged into Branch and thus needs an environment.
+    return true;
+  }
+
+  virtual intptr_t DeoptimizationTarget() const {
+    return GetDeoptId();
+  }
+
+  virtual Representation RequiredInputRepresentation(intptr_t idx) const {
+    return kTagged;
+  }
+
+  virtual EffectSet Effects() const { return EffectSet::None(); }
+
+  virtual bool MayThrow() const { return false; }
+
+  virtual void EmitBranchCode(FlowGraphCompiler* compiler,
+                              BranchInstr* branch);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestSmiInstr);
+};
+
+
 class EqualityCompareInstr : public ComparisonInstr {
  public:
   EqualityCompareInstr(intptr_t token_pos,
@@ -3001,7 +3041,6 @@
 
   DECLARE_INSTRUCTION(EqualityCompare)
   virtual CompileType ComputeType() const;
-  virtual bool RecomputeType();
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;
 
@@ -3051,7 +3090,6 @@
 
   DECLARE_INSTRUCTION(RelationalOp)
   virtual CompileType ComputeType() const;
-  virtual bool RecomputeType();
 
   virtual void PrintOperandsTo(BufferFormatter* f) const;