diff --git a/js/src/jstracer.cpp b/js/src/jstracer.cpp
index 6d3fec3b356..79927340df1 100644
--- a/js/src/jstracer.cpp
+++ b/js/src/jstracer.cpp
@@ -2682,7 +2682,6 @@ void
 nanojit::Fragment::onDestroy()
 {
     if (root == this) {
-        delete mergeCounts;
         delete lirbuf;
     }
     delete (TreeInfo *)vmprivate;
diff --git a/js/src/nanojit/Fragmento.cpp b/js/src/nanojit/Fragmento.cpp
index 04fb3a3b538..5c16a05c5ff 100644
--- a/js/src/nanojit/Fragmento.cpp
+++ b/js/src/nanojit/Fragmento.cpp
@@ -280,7 +280,6 @@ namespace nanojit
         f->anchor = f;
         f->root = f;
         f->kind = LoopTrace;
-        f->mergeCounts = new (_core->gc) BlockHist(_core->gc);
         verbose_only( addLabel(f, "T", _frags->size()); )
         return f;
 	}
@@ -574,7 +573,6 @@ namespace nanojit
 		Fragment *f = newFrag(ip);
 		f->anchor = from->anchor;
 		f->root = from->root;
-		f->mergeCounts = from->anchor->mergeCounts;
         f->xjumpCount = from->xjumpCount;
 		/*// prepend
 		f->nextbranch = from->branches;
diff --git a/js/src/nanojit/Fragmento.h b/js/src/nanojit/Fragmento.h
index 8157b25765b..8357900bef3 100644
--- a/js/src/nanojit/Fragmento.h
+++ b/js/src/nanojit/Fragmento.h
@@ -215,7 +215,6 @@ namespace nanojit
             DWB(Fragment*) parent;
             DWB(Fragment*) first;
             DWB(Fragment*) peer;
-			DWB(BlockHist*) mergeCounts;
             DWB(LirBuffer*) lirbuf;
 			LIns*			lastIns;
 			SideExit*       spawnedFrom;