Index: lib/Transforms/Coroutines/CoroSplit.cpp
===================================================================
--- lib/Transforms/Coroutines/CoroSplit.cpp
+++ lib/Transforms/Coroutines/CoroSplit.cpp
@@ -654,13 +654,25 @@
   // set.
   do {
     Instruction *Current = Work.pop_back_val();
+    DEBUG(dbgs() << "CoroSplit: Will not relocate: " << *Current << "\n");
     DoNotRelocate.insert(Current);
     for (Value *U : Current->operands()) {
       auto *I = dyn_cast<Instruction>(U);
       if (!I)
         continue;
-      if (isa<AllocaInst>(U))
+
+      if (auto *A = dyn_cast<AllocaInst>(I)) {
+        // Stores to alloca instructions that occur before coroutine frame
+        // is allocated should not be moved; the stored values may be used
+        // by the coroutine frame allocator.
+        if (RelocBlocks.count(A->getParent()) != 0) {
+          for (const auto &User : A->users())
+            if (auto *SI = dyn_cast<llvm::StoreInst>(User))
+              DoNotRelocate.insert(SI);
+        }
         continue;
+      }
+
       if (DoNotRelocate.count(I) == 0) {
         Work.push_back(I);
         DoNotRelocate.insert(I);