Shorten live ranges of argument subexpressions.

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 3f48e50e22d765c3f6a26d2f82ec798dd7752a1a..3756beb47bb36543abb21c1b134673a4f444b708 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -1403,8 +1403,10 @@ class LCallGlobal: public LInstruction {
 };
 
 
-class LCallKnownGlobal: public LInstruction {
+class LCallKnownGlobal: public LUnaryOperation {
  public:
+  explicit LCallKnownGlobal(LOperand* receiver) : LUnaryOperation(receiver) { }
+
   DECLARE_CONCRETE_INSTRUCTION(CallKnownGlobal, "call-known-global")
   DECLARE_HYDROGEN_ACCESSOR(CallKnownGlobal)
 
@@ -2104,6 +2106,11 @@ class LChunkBuilder BASE_EMBEDDED {
   LInstruction* DoArithmeticT(Token::Value op,
                               HArithmeticBinaryOperation* instr);
 
+  void DecrementArgumentCount(int amount) {
+    ASSERT(amount <= argument_count_);
+    argument_count_ -= amount;
+  }
+
   LChunk* chunk_;
   HGraph* const graph_;
   Status status_;