[turbofan] Fix more -Wsign-compare warnings.

test/cctest/compiler/test-run-machops.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 <cmath>
 #include <functional>
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/base/ieee754.h"
@@ skipping 6341 matching lines @@
   BufferedRawMachineAssemblerTester<int64_t> m(MachineType::Float64());
   Node* trunc = m.TryTruncateFloat64ToUint64(m.Parameter(0));
   Node* val = m.Projection(0, trunc);
   Node* check = m.Projection(1, trunc);
   m.StoreToPointer(&success, MachineRepresentation::kWord64, check);
   m.Return(val);
 
   FOR_FLOAT64_INPUTS(i) {
     if (*i < 18446744073709551616.0 && *i > -1) {
       // Conversions within this range should succeed.
-      CHECK_EQ(static_cast<uint64_t>(*i), m.Call(*i));
+      CHECK_EQ(static_cast<uint64_t>(*i), static_cast<uint64_t>(m.Call(*i)));
       CHECK_NE(0, success);
     } else {
       m.Call(*i);
       CHECK_EQ(0, success);
     }
   }
 }
 
 
 TEST(RunRoundInt64ToFloat32) {
@@ skipping 308 matching lines @@
   r.Goto(&merge);
   r.Bind(&merge);
   Node* phi = r.Phi(MachineRepresentation::kWord32, fa, fb);
   r.Return(phi);
   CHECK_EQ(1, r.Call(1));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8