[compiler] Fix typing of ToLength.

src/compiler/typer.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/typer.h"
 
 #include <iomanip>
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
@@ skipping 436 matching lines @@
   return t->cache_.kIntegerOrMinusZero;
 }
 
 
 // static
 Type* Typer::Visitor::ToLength(Type* type, Typer* t) {
   // ES6 section 7.1.15 ToLength ( argument )
   type = ToInteger(type, t);
   double min = type->Min();
   double max = type->Max();
+  if (max <= 0.0) {
+    return Type::NewConstant(0, t->zone());
+  }
+  if (min >= kMaxSafeInteger) {
+    return Type::NewConstant(kMaxSafeInteger, t->zone());
+  }
   if (min <= 0.0) min = 0.0;
-  if (max > kMaxSafeInteger) max = kMaxSafeInteger;
-  if (max <= min) max = min;
+  if (max >= kMaxSafeInteger) max = kMaxSafeInteger;
   return Type::Range(min, max, t->zone());
 }
 
 
 // static
 Type* Typer::Visitor::ToName(Type* type, Typer* t) {
   // ES6 section 7.1.14 ToPropertyKey ( argument )
   type = ToPrimitive(type, t);
   if (type->Is(Type::Name())) return type;
   if (type->Maybe(Type::Symbol())) return Type::Name();
@@ skipping 1517 matching lines @@
 Type* Typer::Visitor::TypeConstant(Handle<Object> value) {
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::NewConstant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8