[turbofan] cleanup InstructionOperand a little

src/compiler/register-allocator-verifier.cc

Index: src/compiler/register-allocator-verifier.cc
diff --git a/src/compiler/register-allocator-verifier.cc b/src/compiler/register-allocator-verifier.cc
index 7958ffc6ececd8dfe5d020af0fda464b4bcb33a7..912a4c7d82afcb6f3b9d7f9017ccdfe616a201db 100644
--- a/src/compiler/register-allocator-verifier.cc
+++ b/src/compiler/register-allocator-verifier.cc
@@ -119,7 +119,7 @@ void RegisterAllocatorVerifier::BuildConstraint(const InstructionOperand* op,
   constraint->virtual_register_ = InstructionOperand::kInvalidVirtualRegister;
   if (op->IsConstant()) {
     constraint->type_ = kConstant;
-    constraint->value_ = ConstantOperand::cast(op)->index();
+    constraint->value_ = ConstantOperand::cast(op)->virtual_register();
     constraint->virtual_register_ = constraint->value_;
   } else if (op->IsImmediate()) {
     constraint->type_ = kImmediate;
@@ -180,29 +180,30 @@ void RegisterAllocatorVerifier::CheckConstraint(
   switch (constraint->type_) {
     case kConstant:
       CHECK(op->IsConstant());
-      CHECK_EQ(op->index(), constraint->value_);
+      CHECK_EQ(ConstantOperand::cast(op)->virtual_register(),
+               constraint->value_);
       return;
     case kImmediate:
       CHECK(op->IsImmediate());
-      CHECK_EQ(op->index(), constraint->value_);
+      CHECK_EQ(ImmediateOperand::cast(op)->index(), constraint->value_);
       return;
     case kRegister:
       CHECK(op->IsRegister());
       return;
     case kFixedRegister:
       CHECK(op->IsRegister());
-      CHECK_EQ(op->index(), constraint->value_);
+      CHECK_EQ(RegisterOperand::cast(op)->index(), constraint->value_);
       return;
     case kDoubleRegister:
       CHECK(op->IsDoubleRegister());
       return;
     case kFixedDoubleRegister:
       CHECK(op->IsDoubleRegister());
-      CHECK_EQ(op->index(), constraint->value_);
+      CHECK_EQ(DoubleRegisterOperand::cast(op)->index(), constraint->value_);
       return;
     case kFixedSlot:
       CHECK(op->IsStackSlot());
-      CHECK_EQ(op->index(), constraint->value_);
+      CHECK_EQ(StackSlotOperand::cast(op)->index(), constraint->value_);
       return;
     case kSlot:
       CHECK(op->IsStackSlot());
@@ -343,11 +344,11 @@ class OperandMap : public ZoneObject {
 
   void DropRegisters(const RegisterConfiguration* config) {
     for (int i = 0; i < config->num_general_registers(); ++i) {
-      InstructionOperand op(InstructionOperand::REGISTER, i);
+      RegisterOperand op(i);
       Drop(&op);
     }
     for (int i = 0; i < config->num_double_registers(); ++i) {
-      InstructionOperand op(InstructionOperand::DOUBLE_REGISTER, i);
+      DoubleRegisterOperand op(i);
       Drop(&op);
     }
   }