Support string add in crankshaft:

src/ia32/lithium-ia32.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 21 matching lines @@
 #include "lithium-allocator.h"
 #include "lithium.h"
 #include "safepoint-table.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class LCodeGen;
 
+
 #define LITHIUM_ALL_INSTRUCTION_LIST(V)         \
   V(ControlInstruction)                         \
   V(Call)                                       \
   LITHIUM_CONCRETE_INSTRUCTION_LIST(V)
 
 
 #define LITHIUM_CONCRETE_INSTRUCTION_LIST(V)    \
   V(AccessArgumentsAt)                          \
   V(AddI)                                       \
   V(ApplyArguments)                             \
@@ skipping 95 matching lines @@
   V(SmiUntag)                                   \
   V(StackCheck)                                 \
   V(StoreContextSlot)                           \
   V(StoreGlobalCell)                            \
   V(StoreGlobalGeneric)                         \
   V(StoreKeyedFastElement)                      \
   V(StoreKeyedGeneric)                          \
   V(StoreKeyedSpecializedArrayElement)          \
   V(StoreNamedField)                            \
   V(StoreNamedGeneric)                          \
+  V(StringAdd)                                  \
   V(StringCharCodeAt)                           \
   V(StringCharFromCode)                         \
   V(StringLength)                               \
   V(SubI)                                       \
   V(TaggedToI)                                  \
   V(Throw)                                      \
   V(ToFastProperties)                           \
   V(Typeof)                                     \
   V(TypeofIs)                                   \
   V(TypeofIsAndBranch)                          \
@@ skipping 1595 matching lines @@
   virtual void PrintDataTo(StringStream* stream);
 
   LOperand* context() { return inputs_[0]; }
   LOperand* object() { return inputs_[1]; }
   LOperand* key() { return inputs_[2]; }
   LOperand* value() { return inputs_[3]; }
   bool strict_mode() { return hydrogen()->strict_mode(); }
 };
 
 
+class LStringAdd: public LTemplateInstruction<1, 2, 0> {
+ public:
+  LStringAdd(LOperand* left, LOperand* right) {
+    inputs_[0] = left;
+    inputs_[1] = right;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(StringAdd, "string-add")
+  DECLARE_HYDROGEN_ACCESSOR(StringAdd)
+
+  LOperand* left() { return inputs_[0]; }
+  LOperand* right() { return inputs_[1]; }
+};
+
+
 class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
  public:
   LStringCharCodeAt(LOperand* string, LOperand* index) {
     inputs_[0] = string;
     inputs_[1] = index;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StringCharCodeAt, "string-char-code-at")
   DECLARE_HYDROGEN_ACCESSOR(StringCharCodeAt)
 
@@ skipping 448 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_LITHIUM_IA32_H_