1 files changed, 9 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Coroutines/CoroEarly.cpp b/llvm/lib/Transforms/Coroutines/CoroEarly.cpp
index 1660e41ba830..5e5e513cdfda 100644
--- a/llvm/lib/Transforms/Coroutines/CoroEarly.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroEarly.cpp
@@ -149,6 +149,7 @@ bool Lowerer::lowerEarlyIntrinsics(Function &F) {
   bool Changed = false;
   CoroIdInst *CoroId = nullptr;
   SmallVector<CoroFreeInst *, 4> CoroFrees;
+  bool HasCoroSuspend = false;
   for (auto IB = inst_begin(F), IE = inst_end(F); IB != IE;) {
     Instruction &I = *IB++;
     if (auto *CB = dyn_cast<CallBase>(&I)) {
@@ -163,6 +164,7 @@ bool Lowerer::lowerEarlyIntrinsics(Function &F) {
         // pass expects that there is at most one final suspend point.
         if (cast<CoroSuspendInst>(&I)->isFinal())
           CB->setCannotDuplicate();
+        HasCoroSuspend = true;
         break;
       case Intrinsic::coro_end_async:
       case Intrinsic::coro_end:
@@ -213,6 +215,13 @@ bool Lowerer::lowerEarlyIntrinsics(Function &F) {
   if (CoroId)
     for (CoroFreeInst *CF : CoroFrees)
       CF->setArgOperand(0, CoroId);
+  // Coroutine suspention could potentially lead to any argument modified
+  // outside of the function, hence arguments should not have noalias
+  // attributes.
+  if (HasCoroSuspend)
+    for (Argument &A : F.args())
+      if (A.hasNoAliasAttr())
+        A.removeAttr(Attribute::NoAlias);
   return Changed;
 }