[interpreter] Reduce move operations for wide register support.

src/interpreter/bytecode-array-builder.cc

Index: src/interpreter/bytecode-array-builder.cc
diff --git a/src/interpreter/bytecode-array-builder.cc b/src/interpreter/bytecode-array-builder.cc
index 56cdfb9d82d9873fba68eb3914601cd4d8c54698..af3542197ed5b5e98334017c75be06cba297e52d 100644
--- a/src/interpreter/bytecode-array-builder.cc
+++ b/src/interpreter/bytecode-array-builder.cc
@@ -408,7 +408,7 @@ bool BytecodeArrayBuilder::RegisterOperandIsMovable(Bytecode bytecode,
   // need for a large translation window.
   OperandType operand_type = Bytecodes::GetOperandType(bytecode, operand_index);
   if (operand_type != OperandType::kReg8 &&
-      operand_type != OperandType::kReg16) {

[rmcilroy, 2016/01/26 16:49:51]

Purposefully dropping kReg16 from here?

[oth, 2016/01/26 17:55:53]

Yes, moves to the translation window are not needed for 16-bit register operands
as they are directly addressable by the 16-bit operand.

+      operand_type != OperandType::kRegOut8) {
     return false;
   } else if (operand_index + 1 == Bytecodes::NumberOfOperands(bytecode)) {
     return true;
@@ -1413,8 +1413,11 @@ bool BytecodeArrayBuilder::OperandIsValid(Bytecode bytecode, int operand_index,
       }
     // Fall-through to kReg8 case.
     case OperandType::kReg8:
+    case OperandType::kRegOut8:
       return RegisterIsValid(Register::FromRawOperand(operand_value),
                              operand_type);
+    case OperandType::kRegOutPair8:
+    case OperandType::kRegOutPair16:
     case OperandType::kRegPair8:
     case OperandType::kRegPair16: {
       Register reg0 = Register::FromRawOperand(operand_value);
@@ -1422,8 +1425,8 @@ bool BytecodeArrayBuilder::OperandIsValid(Bytecode bytecode, int operand_index,
       return RegisterIsValid(reg0, operand_type) &&
              RegisterIsValid(reg1, operand_type);
     }
-    case OperandType::kRegTriple8:
-    case OperandType::kRegTriple16: {
+    case OperandType::kRegOutTriple8:
+    case OperandType::kRegOutTriple16: {
       Register reg0 = Register::FromRawOperand(operand_value);
       Register reg1 = Register(reg0.index() + 1);
       Register reg2 = Register(reg0.index() + 2);
@@ -1436,7 +1439,8 @@ bool BytecodeArrayBuilder::OperandIsValid(Bytecode bytecode, int operand_index,
         return true;
       }
     // Fall-through to kReg16 case.
-    case OperandType::kReg16: {
+    case OperandType::kReg16:
+    case OperandType::kRegOut16: {
       Register reg = Register::FromRawOperand(operand_value);
       return RegisterIsValid(reg, operand_type);
     }