Only emit coro.promise if CoroBegin is nonnull

Author: NewSigma

llvm/lib/Transforms/Coroutines/CoroEarly.cpp

@@ -236,10 +236,9 @@ void Lowerer::lowerEarlyIntrinsics(Function &F) {
       case Intrinsic::coro_destroy:
         lowerResumeOrDestroy(*CB, CoroSubFnInst::DestroyIndex);
         break;
-      case Intrinsic::coro_promise: {
+      case Intrinsic::coro_promise:
         lowerCoroPromise(cast<CoroPromiseInst>(&I));
         break;
-      }
       case Intrinsic::coro_done:
         lowerCoroDone(cast<IntrinsicInst>(&I));
         break;
@@ -253,9 +252,9 @@ void Lowerer::lowerEarlyIntrinsics(Function &F) {
     for (CoroFreeInst *CF : CoroFrees)
       CF->setArgOperand(0, CoroId);
 
-    if (auto *PA = CoroId->getPromise()) {
-      assert(CoroBegin && "Use Switch-Resumed ABI but missing coro.begin");
-
+    auto *PA = CoroId->getPromise();
+    if (PA && CoroBegin) {
+      assert(isa<AllocaInst>(PA) && "Must pass alloca to coro.id");
       Builder.SetInsertPoint(*CoroBegin->getInsertionPointAfterDef());
 
       auto *Alignment = Builder.getInt32(PA->getAlign().value());

llvm/test/Instrumentation/AddressSanitizer/skip-coro.ll

@@ -15,9 +15,8 @@ define ptr @foo() #0 {
 entry:
   %__promise = alloca %struct.Promise, align 8
   %0 = call token @llvm.coro.id(i32 16, ptr nonnull %__promise, ptr null, ptr null)
-  %1 = call ptr @llvm.coro.begin(token %0, ptr null)
-  %2 = call ptr @llvm.coro.noop()
-  ret ptr %2
+  %1 = call ptr @llvm.coro.noop()
+  ret ptr %1
 }
 
 declare token @llvm.coro.id(i32, ptr readnone, ptr nocapture readonly, ptr)