[not for landing] Re-shuffle AllocationSite members

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 2bf85f87c2a04592828fbff1f3068582266ed442..21ae07f2d84b6efdab7becb3d632331250860cf9 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -3246,18 +3246,19 @@ void HGraphBuilder::BuildCreateAllocationMemento(
       HObjectAccess::ForAllocationMementoSite(),
       allocation_site);
   if (FLAG_allocation_site_pretenuring) {
-    HValue* memento_create_count =
-        Add<HLoadNamedField>(allocation_site, nullptr,
-                             HObjectAccess::ForAllocationSiteOffset(
-                                 AllocationSite::kPretenureCreateCountOffset));
+    // The memento created counter is embedded in the first 26 bits of pretenure
+    // data. The value itself is bounded by new space size and cleared after
+    // every GC cycle. Overflow into the higher bits is thus not an issue.
+    HValue* memento_create_count = Add<HLoadNamedField>(
+        allocation_site, nullptr, HObjectAccess::ForAllocationSiteOffset(
+                                      AllocationSite::kPretenureDataOffset));
     memento_create_count = AddUncasted<HAdd>(
         memento_create_count, graph()->GetConstant1());
-    // This smi value is reset to zero after every gc, overflow isn't a problem
-    // since the counter is bounded by the new space size.
     memento_create_count->ClearFlag(HValue::kCanOverflow);
-    Add<HStoreNamedField>(
-        allocation_site, HObjectAccess::ForAllocationSiteOffset(
-            AllocationSite::kPretenureCreateCountOffset), memento_create_count);
+    Add<HStoreNamedField>(allocation_site,
+                          HObjectAccess::ForAllocationSiteOffset(
+                              AllocationSite::kPretenureDataOffset),
+                          memento_create_count);
   }
 }