Add range to kBIT_AND with positive constants. Use that range to eliminate compares in left shifts.

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1711 matching lines @@
  public:
   Range(RangeBoundary min, RangeBoundary max) : min_(min), max_(max) { }
 
   static Range* Unknown() {
     return new Range(RangeBoundary::MinSmi(), RangeBoundary::MaxSmi());
   }
 
   void PrintTo(BufferFormatter* f) const;
   static const char* ToCString(Range* range);
 
-  const RangeBoundary& min() { return min_; }
-  const RangeBoundary& max() { return max_; }
+  const RangeBoundary& min() const { return min_; }
+  const RangeBoundary& max() const { return max_; }
 
   bool Equals(Range* other) {
     return min_.Equals(other->min_) && max_.Equals(other->max_);
   }
 
   static bool Update(Range** range_slot,
                      const RangeBoundary& min,
                      const RangeBoundary& max) {
     if (*range_slot == NULL) {
       *range_slot = new Range(min, max);
@@ skipping 14 matching lines @@
   static RangeBoundary ConstantMin(Range* range) {
     if (range == NULL) return RangeBoundary::MinSmi();
     return range->min().LowerBound();
   }
 
   static RangeBoundary ConstantMax(Range* range) {
     if (range == NULL) return RangeBoundary::MaxSmi();
     return range->max().UpperBound();
   }
 
+  // Inclusive.
+  bool IsWithin(intptr_t min_int, intptr_t max_int) const;
+
  private:
   RangeBoundary min_;
   RangeBoundary max_;
 };
 
 
 class ConstraintInstr : public TemplateDefinition<2> {
  public:
   ConstraintInstr(Value* value, Range* constraint)
       : constraint_(constraint) {
@@ skipping 2463 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_