Revert "Minor clarifications and simplifications as well as additional checks."

This reverts commit d32eacbdea3fc0c119da06abe95b07a83c67aa48.

TBR=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/410083005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22569 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/types.cc

@@ -262,7 +262,7 @@ bool TypeImpl<Config>::SlowIs(TypeImpl* that) {
   if (this->IsBitset() && SEMANTIC(this->AsBitset()) == BitsetType::kNone) {
     // Bitsets only have non-bitset supertypes along the representation axis.
     int that_bitset = that->BitsetGlb();
-    return (BitsetType::Is(this->AsBitset(), that_bitset));
+    return (this->AsBitset() | that_bitset) == that_bitset;
   }
 
   if (that->IsClass()) {
@@ -313,12 +313,16 @@ bool TypeImpl<Config>::SlowIs(TypeImpl* that) {
 
   // T <= (T1 \/ ... \/ Tn)  <=>  (T <= T1) \/ ... \/ (T <= Tn)
   // (iff T is not a union)
-  ASSERT(!this->IsUnion() && that->IsUnion());
-  UnionHandle unioned = handle(that->AsUnion());
-  for (int i = 0; i < unioned->Length(); ++i) {
-    if (this->Is(unioned->Get(i))) return true;
-    if (this->IsBitset()) break;  // Fast fail, only first field is a bitset.
+  ASSERT(!this->IsUnion());
+  if (that->IsUnion()) {
+    UnionHandle unioned = handle(that->AsUnion());
+    for (int i = 0; i < unioned->Length(); ++i) {
+      if (this->Is(unioned->Get(i))) return true;
+      if (this->IsBitset()) break;  // Fast fail, only first field is a bitset.
+    }
+    return false;
   }
+
   return false;
 }
 
@@ -378,8 +382,11 @@ bool TypeImpl<Config>::Maybe(TypeImpl* that) {
   }
 
   ASSERT(!this->IsUnion() && !that->IsUnion());
-  if (this->IsBitset() || that->IsBitset()) {
-    return BitsetType::IsInhabited(this->BitsetLub() & that->BitsetLub());
+  if (this->IsBitset()) {
+    return BitsetType::IsInhabited(this->AsBitset() & that->BitsetLub());
+  }
+  if (that->IsBitset()) {
+    return BitsetType::IsInhabited(this->BitsetLub() & that->AsBitset());
   }
   if (this->IsClass()) {
     return that->IsClass()
@@ -437,7 +444,6 @@ template<class Config>
 typename TypeImpl<Config>::TypeHandle TypeImpl<Config>::Narrow(
     int bitset, Region* region) {
   TypeHandle bound = BitsetType::New(bitset, region);
-  ASSERT(!this->IsBitset() && this->Is(bound));
   if (this->IsClass()) {
     return ClassType::New(this->AsClass()->Map(), bound, region);
   } else if (this->IsConstant()) {
@@ -564,7 +570,7 @@ int TypeImpl<Config>::NormalizeUnion(UnionHandle result, int size, int bitset) {
   if (bitset != BitsetType::kNone && SEMANTIC(bitset) == BitsetType::kNone) {
     for (int i = 1; i < size; ++i) {
       int glb = result->Get(i)->BitsetGlb();
-      if (BitsetType::Is(bitset, glb)) {
+      if ((bitset | glb) == glb) {
         for (int j = 1; j < size; ++j) {
           result->Set(j - 1, result->Get(j));
         }

src/types.h

@@ -68,12 +68,11 @@ namespace internal {
 //   None <= R
 //   R <= Any
 //
-//   UntaggedInt = UntaggedInt1 \/ UntaggedInt8 \/
-//                 UntaggedInt16 \/ UntaggedInt32
-//   UntaggedFloat = UntaggedFloat32 \/ UntaggedFloat64
-//   UntaggedNumber = UntaggedInt \/ UntaggedFloat
-//   Untagged = UntaggedNumber \/ UntaggedPtr
-//   Tagged = TaggedInt \/ TaggedPtr
+//   UntaggedInt <= UntaggedInt8 \/ UntaggedInt16 \/ UntaggedInt32)
+//   UntaggedFloat <= UntaggedFloat32 \/ UntaggedFloat64
+//   UntaggedNumber <= UntaggedInt \/ UntaggedFloat
+//   Untagged <= UntaggedNumber \/ UntaggedPtr
+//   Tagged <= TaggedInt \/ TaggedPtr
 //
 // Subtyping relates the two dimensions, for example:
 //
@@ -503,10 +502,6 @@ class TypeImpl<Config>::BitsetType : public TypeImpl<Config> {
     return (bitset & kRepresentation) && (bitset & kSemantic);
   }
 
-  static bool Is(int bitset1, int bitset2) {
-    return (bitset1 | bitset2) == bitset2;
-  }
-
   static int Glb(TypeImpl* type);  // greatest lower bound that's a bitset
   static int Lub(TypeImpl* type);  // least upper bound that's a bitset
   static int Lub(i::Object* value);
@@ -617,7 +612,6 @@ class TypeImpl<Config>::ClassType : public StructuralType {
 
   static ClassHandle New(
       i::Handle<i::Map> map, TypeHandle bound, Region* region) {
-    ASSERT(BitsetType::Is(bound->AsBitset(), BitsetType::Lub(*map)));
     ClassHandle type = Config::template cast<ClassType>(
         StructuralType::New(StructuralType::kClassTag, 2, region));
     type->Set(0, bound);
@@ -654,7 +648,6 @@ class TypeImpl<Config>::ConstantType : public StructuralType {
 
   static ConstantHandle New(
       i::Handle<i::Object> value, TypeHandle bound, Region* region) {
-    ASSERT(BitsetType::Is(bound->AsBitset(), BitsetType::Lub(*value)));
     ConstantHandle type = Config::template cast<ConstantType>(
         StructuralType::New(StructuralType::kConstantTag, 2, region));
     type->Set(0, bound);
@@ -686,7 +679,8 @@ class TypeImpl<Config>::RangeType : public StructuralType {
 
   static RangeHandle New(
       double min, double max, TypeHandle bound, Region* region) {
-    ASSERT(BitsetType::Is(bound->AsBitset(), BitsetType::kNumber));
+    ASSERT(SEMANTIC(bound->AsBitset() | BitsetType::kNumber)
+           == SEMANTIC(BitsetType::kNumber));
     ASSERT(!std::isnan(min) && !std::isnan(max) && min <= max);
     RangeHandle type = Config::template cast<RangeType>(
         StructuralType::New(StructuralType::kRangeTag, 3, region));
@@ -721,8 +715,6 @@ class TypeImpl<Config>::ContextType : public StructuralType {
   TypeHandle Outer() { return this->Get(1); }
 
   static ContextHandle New(TypeHandle outer, TypeHandle bound, Region* region) {
-    ASSERT(BitsetType::Is(
-        bound->AsBitset(), BitsetType::kInternal & BitsetType::kTaggedPtr));
     ContextHandle type = Config::template cast<ContextType>(
         StructuralType::New(StructuralType::kContextTag, 2, region));
     type->Set(0, bound);
@@ -753,7 +745,7 @@ class TypeImpl<Config>::ArrayType : public StructuralType {
   TypeHandle Element() { return this->Get(1); }
 
   static ArrayHandle New(TypeHandle element, TypeHandle bound, Region* region) {
-    ASSERT(BitsetType::Is(bound->AsBitset(), BitsetType::kArray));
+    ASSERT(SEMANTIC(bound->AsBitset()) == SEMANTIC(BitsetType::kArray));
     ArrayHandle type = Config::template cast<ArrayType>(
         StructuralType::New(StructuralType::kArrayTag, 2, region));
     type->Set(0, bound);
@@ -790,7 +782,7 @@ class TypeImpl<Config>::FunctionType : public StructuralType {
   static FunctionHandle New(
       TypeHandle result, TypeHandle receiver, TypeHandle bound,
       int arity, Region* region) {
-    ASSERT(BitsetType::Is(bound->AsBitset(), BitsetType::kFunction));
+    ASSERT(SEMANTIC(bound->AsBitset()) == SEMANTIC(BitsetType::kFunction));
     FunctionHandle type = Config::template cast<FunctionType>(
         StructuralType::New(StructuralType::kFunctionTag, 3 + arity, region));
     type->Set(0, bound);