Use register allocator for context on x64.

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 a016cfb036af81f7c69bdf946515d03a55450475..a4bdb2c2d6719dd3fb9c8e59c78c7b024bebdb4a 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -740,15 +740,13 @@ class LMathFloor V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathRound V8_FINAL : public LTemplateInstruction<1, 2, 1> {
+class LMathRound V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
-  LMathRound(LOperand* context, LOperand* value, LOperand* temp) {
-    inputs_[1] = context;
+  LMathRound(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
     temps_[0] = temp;
   }
 
-  LOperand* context() { return inputs_[1]; }
   LOperand* value() { return inputs_[0]; }
   LOperand* temp() { return temps_[0]; }
 
@@ -851,15 +849,13 @@ class LMathSqrt V8_FINAL : public LTemplateInstruction<1, 1, 0> {
 };
 
 
-class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 2, 1> {
+class LMathPowHalf V8_FINAL : public LTemplateInstruction<1, 1, 1> {
  public:
-  LMathPowHalf(LOperand* context, LOperand* value, LOperand* temp) {
-    inputs_[1] = context;
+  LMathPowHalf(LOperand* value, LOperand* temp) {
     inputs_[0] = value;
     temps_[0] = temp;
   }
 
-  LOperand* context() { return inputs_[1]; }
   LOperand* value() { return inputs_[0]; }
   LOperand* temp() { return temps_[0]; }
 
@@ -968,6 +964,7 @@ class LStringCompareAndBranch V8_FINAL : public LControlInstruction<3, 0> {
     inputs_[2] = right;
   }
 
+  LOperand* context() { return inputs_[1]; }
   LOperand* left() { return inputs_[1]; }
   LOperand* right() { return inputs_[2]; }
 
@@ -1072,6 +1069,7 @@ class LCmpT V8_FINAL : public LTemplateInstruction<1, 3, 0> {
   DECLARE_CONCRETE_INSTRUCTION(CmpT, "cmp-t")
   DECLARE_HYDROGEN_ACCESSOR(CompareGeneric)
 
+  LOperand* context() { return inputs_[0]; }
   Token::Value op() const { return hydrogen()->token(); }
 };
 
@@ -1098,6 +1096,7 @@ class LInstanceOfKnownGlobal V8_FINAL : public LTemplateInstruction<1, 2, 1> {
     temps_[0] = temp;
   }
 
+  LOperand* context() { return inputs_[0]; }
   LOperand* value() { return inputs_[1]; }
   LOperand* temp() { return temps_[0]; }
 
@@ -1501,7 +1500,8 @@ class LArithmeticT V8_FINAL : public LTemplateInstruction<1, 3, 0> {
 
 class LReturn V8_FINAL : public LTemplateInstruction<0, 3, 0> {
  public:
-  explicit LReturn(LOperand* value, LOperand* context,
+  explicit LReturn(LOperand* value,
+                   LOperand* context,
                    LOperand* parameter_count) {
     inputs_[0] = value;
     inputs_[1] = context;