2 files changed, 28 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index 318a012b6a7..1183352271c 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -585,8 +585,25 @@ void CoroCloner::create() {
 
   SmallVector<ReturnInst *, 4> Returns;
 
+  // Ignore attempts to change certain attributes of the function.
+  // TODO: maybe there should be a way to suppress this during cloning?
+  auto savedVisibility = NewF->getVisibility();
+  auto savedUnnamedAddr = NewF->getUnnamedAddr();
+  auto savedDLLStorageClass = NewF->getDLLStorageClass();
+
+  // NewF's linkage (which CloneFunctionInto does *not* change) might not
+  // be compatible with the visibility of OrigF (which it *does* change),
+  // so protect against that.
+  auto savedLinkage = NewF->getLinkage();
+  NewF->setLinkage(llvm::GlobalValue::ExternalLinkage);
+
   CloneFunctionInto(NewF, &OrigF, VMap, /*ModuleLevelChanges=*/true, Returns);
 
+  NewF->setLinkage(savedLinkage);
+  NewF->setVisibility(savedVisibility);
+  NewF->setUnnamedAddr(savedUnnamedAddr);
+  NewF->setDLLStorageClass(savedDLLStorageClass);
+
   auto &Context = NewF->getContext();
 
   // Replace the attributes of the new function:
diff --git a/llvm/lib/Transforms/Coroutines/Coroutines.cpp b/llvm/lib/Transforms/Coroutines/Coroutines.cpp
index b81a08557b4..12176570b7a 100644
--- a/llvm/lib/Transforms/Coroutines/Coroutines.cpp
+++ b/llvm/lib/Transforms/Coroutines/Coroutines.cpp
@@ -405,7 +405,17 @@ void coro::Shape::buildFrom(Function &F) {
       auto SI = Suspend->value_begin(), SE = Suspend->value_end();
       auto RI = ResultTys.begin(), RE = ResultTys.end();
       for (; SI != SE && RI != RE; ++SI, ++RI) {
-        if ((*SI)->getType() != *RI) {
+        auto SrcTy = (*SI)->getType();
+        if (SrcTy != *RI) {
+          // The optimizer likes to eliminate bitcasts leading into variadic
+          // calls, but that messes with our invariants.  Re-insert the
+          // bitcast and ignore this type mismatch.
+          if (CastInst::isBitCastable(SrcTy, *RI)) {
+            auto BCI = new BitCastInst(*SI, *RI, "", Suspend);
+            SI->set(BCI);
+            continue;
+          }
+
 #ifndef NDEBUG
           Suspend->dump();
           Prototype->getFunctionType()->dump();