Add an untagged double to transcendental cache elements. They now contain an...

src/heap.h

Index: src/heap.h
===================================================================
--- src/heap.h	(revision 6110)
+++ src/heap.h	(working copy)
@@ -1999,9 +1999,19 @@
     Element e = elements_[hash];
     if (e.in[0] == c.integers[0] &&
         e.in[1] == c.integers[1]) {
-      ASSERT(e.output != NULL);
-      Counters::transcendental_cache_hit.Increment();
-      return e.output;
+      if (e.output != NULL) {
+        Counters::transcendental_cache_hit.Increment();
+        return e.output;
+      } else {
+        Object* heap_number;
+        { MaybeObject* maybe_heap_number =
+              Heap::AllocateHeapNumber(e.untagged_output);
+          if (!maybe_heap_number->ToObject(&heap_number))
+            return maybe_heap_number;
+        }
+        elements_[hash].output = heap_number;
+        return heap_number;
+      }
     }
     double answer = Calculate(input);
     Counters::transcendental_cache_miss.Increment();
@@ -2012,6 +2022,7 @@
     elements_[hash].in[0] = c.integers[0];
     elements_[hash].in[1] = c.integers[1];
     elements_[hash].output = heap_number;
+    elements_[hash].untagged_output = answer;
     return heap_number;
   }
 
@@ -2041,7 +2052,9 @@
   struct Element {
     uint32_t in[2];
     Object* output;
+    double untagged_output;
   };
+  static const int kElementSize = sizeof(Element);  // NOLINT
   union Converter {
     double dbl;
     uint32_t integers[2];