Fix -Wsign-compare warnings in parser, scanner, regexp, runtime.

src/regexp/regexp-parser.cc

 // Copyright 2016 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/regexp/regexp-parser.h"
 
 #include "src/char-predicates-inl.h"
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
@@ skipping 1589 matching lines @@
     if (characters_ == NULL) {
       characters_ = new (zone()) ZoneList<uc16>(4, zone());
     }
     characters_->Add(c, zone());
     LAST(ADD_CHAR);
   }
 }
 
 
 void RegExpBuilder::AddUnicodeCharacter(uc32 c) {
-  if (c > unibrow::Utf16::kMaxNonSurrogateCharCode) {
+  if (c > static_cast<uc32>(unibrow::Utf16::kMaxNonSurrogateCharCode)) {
     DCHECK(unicode());
     AddLeadSurrogate(unibrow::Utf16::LeadSurrogate(c));
     AddTrailSurrogate(unibrow::Utf16::TrailSurrogate(c));
   } else if (unicode() && unibrow::Utf16::IsLeadSurrogate(c)) {
     AddLeadSurrogate(c);
   } else if (unicode() && unibrow::Utf16::IsTrailSurrogate(c)) {
     AddTrailSurrogate(c);
   } else {
     AddCharacter(static_cast<uc16>(c));
   }
@@ skipping 166 matching lines @@
     return false;
   }
   terms_.Add(new (zone()) RegExpQuantifier(min, max, quantifier_type, atom),
              zone());
   LAST(ADD_TERM);
   return true;
 }
 
 }  // namespace internal
 }  // namespace v8