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

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 6318 matching lines @@
     case Token::kGT: return (result > 0);
     case Token::kLTE: return (result <= 0);
     case Token::kGTE: return (result >= 0);
     default:
       UNREACHABLE();
       return false;
   }
 }
 
 
+void ConstantPropagator::VisitTestSmi(TestSmiInstr* instr) {
+  const Object& left = instr->left()->definition()->constant_value();
+  const Object& right = instr->right()->definition()->constant_value();
+  if (IsNonConstant(left) || IsNonConstant(right)) {
+    SetValue(instr, non_constant_);
+  } else if (IsConstant(left) && IsConstant(right)) {
+    if (left.IsInteger() && right.IsInteger()) {
+      const bool result = CompareIntegers(
+          instr->kind(),
+          Integer::Handle(Integer::Cast(left).BitOp(Token::kBIT_AND,
+                                                    Integer::Cast(right))),
+          Smi::Handle(Smi::New(0)));
+      SetValue(instr, result ? Bool::True() : Bool::False());
+    } else {
+      SetValue(instr, non_constant_);
+    }
+  }
+}
+
+
 void ConstantPropagator::VisitEqualityCompare(EqualityCompareInstr* instr) {
   const Object& left = instr->left()->definition()->constant_value();
   const Object& right = instr->right()->definition()->constant_value();
 
   if (instr->left()->definition() == instr->right()->definition()) {
     // Fold x == x, and x != x to true/false for numbers comparisons.
     if (RawObject::IsIntegerClassId(instr->operation_cid())) {
       return SetValue(instr, Bool::Get(instr->kind() == Token::kEQ));
     }
   }
@@ skipping 1498 matching lines @@
   }
 
   // Insert materializations at environment uses.
   for (intptr_t i = 0; i < exits.length(); i++) {
     CreateMaterializationAt(exits[i], alloc, alloc->cls(), *fields);
   }
 }
 
 
 }  // namespace dart