Fix a few nits found by PVS Studio

src/hydrogen.cc

 // Copyright 2013 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/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 12625 matching lines @@
       "----------------------------------------\n");
   PrintF("%33s %8.3f ms           %9u bytes\n", "Total",
          total.InMillisecondsF(), total_size_);
   PrintF("%33s     (%.1f times slower than full code gen)\n", "",
          total.TimesOf(full_code_gen_));
 
   double source_size_in_kb = static_cast<double>(source_size_) / 1024;
   double normalized_time =  source_size_in_kb > 0
       ? total.InMillisecondsF() / source_size_in_kb
       : 0;
-  double normalized_size_in_kb = source_size_in_kb > 0
-      ? total_size_ / 1024 / source_size_in_kb
-      : 0;
+  double normalized_size_in_kb =
+      source_size_in_kb > 0
+          ? static_cast<double>(total_size_) / 1024 / source_size_in_kb
+          : 0;
   PrintF("%33s %8.3f ms           %7.3f kB allocated\n",
          "Average per kB source", normalized_time, normalized_size_in_kb);
 }
 
 
 void HStatistics::SaveTiming(const char* name, base::TimeDelta time,
                              unsigned size) {
   total_size_ += size;
   for (int i = 0; i < names_.length(); ++i) {
     if (strcmp(names_[i], name) == 0) {
@@ skipping 12 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal