Basic support for LICM of fully invariant loads.

runtime/vm/intermediate_language.h

 // 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.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 600 matching lines @@
     FOR_EACH_INSTRUCTION(DECLARE_TAG)
   };
 #undef DECLARE_TAG
 
   Instruction()
       : deopt_id_(Isolate::Current()->GetNextDeoptId()),
         lifetime_position_(-1),
         previous_(NULL),
         next_(NULL),
         env_(NULL),
-        expr_id_(-1) { }
+        expr_id_(kNoExprId) { }
 
   virtual Tag tag() const = 0;
 
   intptr_t deopt_id() const {
     ASSERT(CanDeoptimize() || CanBeDeoptimizationTarget());
     return deopt_id_;
   }
 
   bool IsBlockEntry() { return (AsBlockEntry() != NULL); }
   virtual BlockEntryInstr* AsBlockEntry() { return NULL; }
@@ skipping 155 matching lines @@
 
   // Returns set of effects that affect this instruction.
   virtual EffectSet Dependencies() const {
     UNREACHABLE();
     return EffectSet::All();
   }
 
   // Get the block entry for this instruction.
   virtual BlockEntryInstr* GetBlock() const;
 
-  // Id for instructions used in CSE.
+  // Id for load instructions used during load forwarding pass and later in
+  // LICM.
   intptr_t expr_id() const { return expr_id_; }
   void set_expr_id(intptr_t expr_id) { expr_id_ = expr_id; }
+  bool HasExprId() const { return expr_id_ != kNoExprId; }
 
   // Returns a hash code for use with hash maps.
   virtual intptr_t Hashcode() const;
 
   // Compares two instructions.  Returns true, iff:
   // 1. They have the same tag.
   // 2. All input operands are Equals.
   // 3. They satisfy AttributesEqual.
   bool Equals(Instruction* other) const;
 
@@ skipping 71 matching lines @@
   friend class TargetEntryInstr;
   friend class JoinEntryInstr;
   friend class InstanceOfInstr;
   friend class PolymorphicInstanceCallInstr;
   friend class SmiToDoubleInstr;
   friend class DoubleToIntegerInstr;
   friend class BranchSimplifier;
 
   virtual void RawSetInputAt(intptr_t i, Value* value) = 0;
 
+  enum {
+    kNoExprId = -1
+  };
+
   intptr_t deopt_id_;
   intptr_t lifetime_position_;  // Position used by register allocator.
   Instruction* previous_;
   Instruction* next_;
   Environment* env_;
   intptr_t expr_id_;
 
   DISALLOW_COPY_AND_ASSIGN(Instruction);
 };
 
@@ skipping 5170 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_