Index: include/llvm/Support/ArrayRecycler.h
===================================================================
--- include/llvm/Support/ArrayRecycler.h
+++ include/llvm/Support/ArrayRecycler.h
@@ -48,6 +48,8 @@
     FreeList *Entry = Bucket[Idx];
     if (!Entry)
       return nullptr;
+    __asan_unpoison_memory_region(Entry,
+                                  sizeof(T) * Capacity::get(Idx).getSize());
     Bucket[Idx] = Entry->Next;
     return reinterpret_cast<T*>(Entry);
   }
@@ -60,6 +62,8 @@
       Bucket.resize(size_t(Idx) + 1);
     Entry->Next = Bucket[Idx];
     Bucket[Idx] = Entry;
+    __asan_poison_memory_region(Entry,
+                                sizeof(T) * Capacity::get(Idx).getSize());
   }
 
 public:
Index: include/llvm/Support/Recycler.h
===================================================================
--- include/llvm/Support/Recycler.h
+++ include/llvm/Support/Recycler.h
@@ -43,6 +43,9 @@
 
   FreeNode *pop_val() {
     auto *Val = FreeList;
+    // Always unpoison the full Size, because the combiner relies on being able
+    // to morph SDNodes into MachineSDNodes.
+    __asan_unpoison_memory_region(FreeList, Size);
     FreeList = FreeList->Next;
     return Val;
   }
@@ -50,6 +53,7 @@
   void push(FreeNode *N) {
     N->Next = FreeList;
     FreeList = N;
+    __asan_poison_memory_region(FreeList, Size);
   }
 
 public: