Extend some operations to range types.

src/types.h

Index: src/types.h
diff --git a/src/types.h b/src/types.h
index f141712bb84f09c5e58124174517eadc7a2241f6..711d2eebb99a3b38d5ebfd41a9bfbd683af02f88 100644
--- a/src/types.h
+++ b/src/types.h
@@ -285,7 +285,7 @@ class TypeImpl : public Config::Base {
     return ClassType::New(map, region);
   }
   static TypeHandle Constant(i::Handle<i::Object> value, Region* region) {
-    // TODO(neis): return RangeType for numerical values
+    // TODO(neis): Return RangeType for numerical values.
     return ConstantType::New(value, region);
   }
   static TypeHandle Range(double min, double max, Region* region) {
@@ -514,6 +514,7 @@ class TypeImpl<Config>::BitsetType : public TypeImpl<Config> {
   static int Lub(int32_t value);
   static int Lub(uint32_t value);
   static int Lub(i::Map* map);
+  static int RangeLub(double min, double max, TypeHandle bound);

[rossberg, 2014/08/05 14:49:15]

Is this defined anywhere?

[neis, 2014/08/06 13:15:01]

Oops, was a leftover.

   static int InherentLub(TypeImpl* type);
 
   static const char* Name(int bitset);
@@ -684,10 +685,37 @@ class TypeImpl<Config>::RangeType : public StructuralType {
   double Min() { return this->template GetValue<i::HeapNumber>(1)->value(); }
   double Max() { return this->template GetValue<i::HeapNumber>(2)->value(); }
 
+  static bool le(double x, double y) {

[rossberg, 2014/08/05 14:49:15]

These are helpers that shouldn't pollute the public interface. Maybe just make
them static global functions in types.cc?

[neis, 2014/08/06 13:15:01]

Done.

+    return x <= y && copysign(1, x) <= copysign(1, y);
+  }
+  static bool eq(double x, double y) {
+    return le(x, y) && le(y, x);
+  }
+  static double min(double x, double y) {
+    return le(x, y) ? x : y;
+  }
+  static double max(double x, double y) {
+    return le(x, y) ? y : x;
+  }
+
+  static int InherentLub(double min, double max) {

[rossberg, 2014/08/05 14:49:15]

Rename/move this to BitsetType::Lub(double, double), since it's also just an
internal helper.

[neis, 2014/08/06 13:15:01]

Done.

+    DCHECK(le(min, max));
+    DisallowHeapAllocation no_allocation;
+    if (min == max) {

[rossberg, 2014/08/05 14:49:15]

eq(min, max)

[neis, 2014/08/06 13:15:01]

Done.

+      return BitsetType::Lub(min);  // Singleton range.
+    }
+    int bitset = BitsetType::kNumber ^ SEMANTIC(BitsetType::kNaN);
+    if (le(0, min) || max < 0)
+      bitset ^= SEMANTIC(BitsetType::kMinusZero);
+    return bitset;
+    // TODO(neis): Could refine this further by doing more checks on min/max.
+  }
+
   static RangeHandle New(
       double min, double max, TypeHandle bound, Region* region) {
-    DCHECK(BitsetType::Is(bound->AsBitset(), BitsetType::kNumber));
-    DCHECK(!std::isnan(min) && !std::isnan(max) && min <= max);
+    DCHECK(le(min, max));
+    DCHECK(bound->IsBitset());
+    DCHECK(BitsetType::Is(bound->AsBitset(), InherentLub(min, max)));
     RangeHandle type = Config::template cast<RangeType>(
         StructuralType::New(StructuralType::kRangeTag, 3, region));
     type->Set(0, bound);
@@ -700,7 +728,7 @@ class TypeImpl<Config>::RangeType : public StructuralType {
   }
 
   static RangeHandle New(double min, double max, Region* region) {
-    TypeHandle bound = BitsetType::New(BitsetType::kNumber, region);
+    TypeHandle bound = BitsetType::New(InherentLub(min, max), region);
     return New(min, max, bound, region);
   }