[WIP] Typ aided removal of redundant modulus.

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/bootstrapper.h"
 #include "src/compiler/graph-inl.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node.h"
 #include "src/compiler/node-properties-inl.h"
 #include "src/compiler/node-properties.h"
@@ skipping 449 matching lines @@
 Type* Typer::Visitor::ToString(Type* type, Typer* t) {
   if (type->Is(Type::String())) return type;
   return Type::String();
 }
 
 
 Type* Typer::Visitor::NumberToInt32(Type* type, Typer* t) {
   // TODO(neis): DCHECK(type->Is(Type::Number()));
   if (type->Is(Type::Signed32())) return type;
   if (type->Is(t->zeroish)) return t->singleton_zero;
+  if (type->Is(Type::Union(Type::MinusZero(), Type::Signed32(), t->zone()))) {
+    return Type::Intersect(Type::Union(type, t->singleton_zero, t->zone()),
+                           Type::Signed32(), t->zone());
+  }
   return Type::Signed32();
 }
 
 
 Type* Typer::Visitor::NumberToUint32(Type* type, Typer* t) {
   // TODO(neis): DCHECK(type->Is(Type::Number()));
   if (type->Is(Type::Unsigned32())) return type;
   if (type->Is(t->zeroish)) return t->singleton_zero;
   return Type::Unsigned32();
 }
@@ skipping 1480 matching lines @@
         return typer_->float64_array_fun_;
       }
     }
   }
   return Type::Constant(value, zone());
 }
 
 }
 }
 }  // namespace v8::internal::compiler