Use a special EnumLength field to indicate number of valid enum cache values.

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index ee9bf79601da0a1f1bd9b97ed9fb33b172d89e6f..ddcf1021abde5fe5799c16d4aca6eae1e5dbcd15 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -90,6 +90,7 @@ class LCodeGen;
   V(ElementsKind)                               \
   V(FastLiteral)                                \
   V(FixedArrayBaseLength)                       \
+  V(MapEnumLength)                              \

[Michael Starzinger, 2012/08/06 15:06:22]

Alpha-sort!

[Toon Verwaest, 2012/08/07 10:49:47]

Done.

   V(FunctionLiteral)                            \
   V(GetCachedArrayIndex)                        \
   V(GlobalObject)                               \
@@ -1011,6 +1012,18 @@ class LFixedArrayBaseLength: public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LMapEnumLength: public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LMapEnumLength(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(MapEnumLength,
+                               "map-enum-length")
+  DECLARE_HYDROGEN_ACCESSOR(MapEnumLength)
+};
+
+
 class LElementsKind: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LElementsKind(LOperand* value) {