[turbofan] Fix value output count for the Start node.

src/compiler/verifier.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 "src/compiler/verifier.h"
 
 #include <algorithm>
 #include <deque>
 #include <queue>
 #include <sstream>
@@ skipping 300 matching lines @@
       CHECK_EQ(2, input_count);
       // Type is empty.
       CheckNotTyped(node);
       break;
 
     // Common operators
     // ----------------
     case IrOpcode::kParameter: {
       // Parameters have the start node as inputs.
       CHECK_EQ(1, input_count);
-      CHECK_EQ(IrOpcode::kStart,
-               NodeProperties::GetValueInput(node, 0)->opcode());
       // Parameter has an input that produces enough values.
-      int index = OpParameter<int>(node);
-      Node* input = NodeProperties::GetValueInput(node, 0);
+      int const index = ParameterIndexOf(node->op());
+      Node* const start = NodeProperties::GetValueInput(node, 0);
+      CHECK_EQ(IrOpcode::kStart, start->opcode());
       // Currently, parameter indices start at -1 instead of 0.
-      CHECK_GT(input->op()->ValueOutputCount(), index + 1);
+      CHECK_LE(-1, index);
+      CHECK_LT(index + 1, start->op()->ValueOutputCount());
       // Type can be anything.
       CheckUpperIs(node, Type::Any());
       break;
     }
     case IrOpcode::kInt32Constant:  // TODO(rossberg): rename Word32Constant?
       // Constants have no inputs.
       CHECK_EQ(0, input_count);
       // Type is a 32 bit integer, signed or unsigned.
       CheckUpperIs(node, Type::Integral32());
       break;
@@ skipping 810 matching lines @@
     // Check inputs for all nodes in the block.
     for (size_t i = 0; i < block->NodeCount(); i++) {
       Node* node = block->NodeAt(i);
       CheckInputsDominate(schedule, block, node, static_cast<int>(i) - 1);
     }
   }
 }
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8