[turbofan] Fix several int vs size_t issues.

src/compiler/x64/instruction-selector-x64.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 <algorithm>
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 328 matching lines @@
   if (cont->IsBranch()) {
     inputs[input_count++] = g.Label(cont->true_block());
     inputs[input_count++] = g.Label(cont->false_block());
   }
 
   outputs[output_count++] = g.DefineSameAsFirst(node);
   if (cont->IsSet()) {
     outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
-  DCHECK_NE(0, static_cast<int>(input_count));
-  DCHECK_NE(0, static_cast<int>(output_count));
+  DCHECK_NE(0u, input_count);
+  DCHECK_NE(0u, output_count);
   DCHECK_GE(arraysize(inputs), input_count);
   DCHECK_GE(arraysize(outputs), output_count);
 
   Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
                                       outputs, input_count, inputs);
   if (cont->IsBranch()) instr->MarkAsControl();
 }
 
 
 // Shared routine for multiple binary operations.
@@ skipping 103 matching lines @@
 void EmitLea(InstructionSelector* selector, InstructionCode opcode,
              Node* result, Node* index, int scale, Node* base,
              Node* displacement) {
   X64OperandGenerator g(selector);
 
   InstructionOperand inputs[4];
   size_t input_count = 0;
   AddressingMode mode = g.GenerateMemoryOperandInputs(
       index, scale, base, displacement, inputs, &input_count);
 
-  DCHECK_NE(0, static_cast<int>(input_count));
+  DCHECK_NE(0u, input_count);
   DCHECK_GE(arraysize(inputs), input_count);
 
   InstructionOperand outputs[1];
   outputs[0] = g.DefineAsRegister(result);
 
   opcode = AddressingModeField::encode(mode) | opcode;
 
   selector->Emit(opcode, 1, outputs, input_count, inputs);
 }
 
@@ skipping 919 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8