[turbofan] cleanup InstructionOperand a little

test/unittests/compiler/instruction-selector-unittest.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "test/unittests/compiler/instruction-selector-unittest.h"
 
 #include "src/compiler/graph.h"
 #include "src/compiler/schedule.h"
 #include "src/flags.h"
 #include "test/unittests/compiler/compiler-test-utils.h"
@@ skipping 58 matching lines @@
           continue;
       }
     }
     if (mode == kAllExceptNopInstructions && instr->arch_opcode() == kArchNop) {
       continue;
     }
     for (size_t i = 0; i < instr->OutputCount(); ++i) {
       InstructionOperand* output = instr->OutputAt(i);
       EXPECT_NE(InstructionOperand::IMMEDIATE, output->kind());
       if (output->IsConstant()) {
-        s.constants_.insert(std::make_pair(
-            output->index(), sequence.GetConstant(output->index())));
+        int vreg = ConstantOperand::cast(output)->virtual_register();
+        s.constants_.insert(std::make_pair(vreg, sequence.GetConstant(vreg)));
       }
     }
     for (size_t i = 0; i < instr->InputCount(); ++i) {
       InstructionOperand* input = instr->InputAt(i);
       EXPECT_NE(InstructionOperand::CONSTANT, input->kind());
       if (input->IsImmediate()) {
-        s.immediates_.insert(std::make_pair(
-            input->index(), sequence.GetImmediate(input->index())));
+        int index = ImmediateOperand::cast(input)->index();
+        s.immediates_.insert(
+            std::make_pair(index, sequence.GetImmediate(index)));
       }
     }
     s.instructions_.push_back(instr);
   }
   for (auto i : s.virtual_registers_) {
     int const virtual_register = i.second;
     if (sequence.IsDouble(virtual_register)) {
       EXPECT_FALSE(sequence.IsReference(virtual_register));
       s.doubles_.insert(virtual_register);
     }
@@ skipping 483 matching lines @@
   EXPECT_EQ(s.ToVreg(context2), s.ToVreg(call_instr->InputAt(12)));
   // Continuation.
 
   EXPECT_EQ(kArchRet, s[index++]->arch_opcode());
   EXPECT_EQ(index, s.size());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8