Adapt Danno's Track Allocation Info idea to fast literals. When allocating a literal array,

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
diff --git a/src/ia32/codegen-ia32.cc b/src/ia32/codegen-ia32.cc
index 45a968d6b0cdb8bbf0ef64b9056e25bd69e6a5ca..1e22c5c97147f8e78f69dade602ee79a9e400364 100644
--- a/src/ia32/codegen-ia32.cc
+++ b/src/ia32/codegen-ia32.cc
@@ -388,6 +388,7 @@ OS::MemCopyFunction CreateMemCopyFunction() {
 
 #define __ ACCESS_MASM(masm)
 
+
 void ElementsTransitionGenerator::GenerateMapChangeElementsTransition(
     MacroAssembler* masm) {
   // ----------- S t a t e -------------
@@ -420,6 +421,10 @@ void ElementsTransitionGenerator::GenerateSmiToDouble(
   // -----------------------------------
   Label loop, entry, convert_hole, gc_required, only_change_map;
 
+  if (FLAG_use_allocation_site_info) {
+    masm->PerformAllocationSiteInfoCheck(fail);
+  }
+
   // Check for empty arrays, which only require a map transition and no changes
   // to the backing store.
   __ mov(edi, FieldOperand(edx, JSObject::kElementsOffset));
@@ -555,6 +560,11 @@ void ElementsTransitionGenerator::GenerateDoubleToObject(
   // -----------------------------------
   Label loop, entry, convert_hole, gc_required, only_change_map, success;
 
+  // TODO(mvstanton): let's not pre-transition for the double->object case.
+  // if (FLAG_use_allocation_site_info) {
+  //   masm->PerformAllocationSiteInfoCheck(fail);
+  // }

[danno, 2013/01/04 08:50:55]

Just remove this altogether rather than leave it uncommented.

[mvstanton, 2013/01/04 12:07:52]

Done.

+
   // Check for empty arrays, which only require a map transition and no changes
   // to the backing store.
   __ mov(edi, FieldOperand(edx, JSObject::kElementsOffset));