[WIP] Modulus on copy.js.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index 0fa2b95ebd3460350def99acdd14b2341d7b1b00..914174eea8ed2ce04326e0f721c001b8f75e2537 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -467,6 +467,10 @@ 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;
+  Type* intish = Type::Union(Type::Signed32(), t->zeroish, t->zone());
+  if (type->Is(intish)) {
+    return Type::Intersect(Type::Signed32(), type, t->zone());
+  }
   return Type::Signed32();
 }
 
@@ -725,6 +729,10 @@ Type* Typer::Visitor::JSBitwiseOrTyper(Type* lhs, Type* rhs, Typer* t) {
     Handle<Object> max = f->NewNumber(-1);
     return Type::Range(min, max, t->zone());
   }
+  if (rmax == 0 && rmin == 0) {
+    Handle<Object> max = f->NewNumber(lmax);
+    return Type::Range(min, max, t->zone());
+  }
   Handle<Object> max = f->NewNumber(Type::Signed32()->Max());
   return Type::Range(min, max, t->zone());
   // TODO(neis): Be precise for singleton inputs, here and elsewhere.
@@ -1033,8 +1041,7 @@ Type* Typer::Visitor::JSModulusTyper(Type* lhs, Type* rhs, Typer* t) {
   lhs = Rangify(lhs, t);
   rhs = Rangify(rhs, t);
   if (lhs->IsRange() && rhs->IsRange()) {
-    // TODO(titzer): fix me.
-    //    return JSModulusRanger(lhs->AsRange(), rhs->AsRange(), t);
+    return JSModulusRanger(lhs->AsRange(), rhs->AsRange(), t);
   }
   return Type::OrderedNumber();
 }