[Coro] Delete ret.popless before rewritten return.

llvm/lib/Transforms/Coroutines/CoroSplit.cpp

@@ -966,6 +966,18 @@ static void addSwiftSelfAttrs(AttributeList &Attrs, LLVMContext &Context,
   Attrs = Attrs.addParamAttributes(Context, ParamIndex, ParamAttrs);
 }
 
+static void eraseIntrinsicRetPoplessBefore(ReturnInst *Return) {
+  if (Return == &*Return->getParent()->begin())
+    return;
+  auto *Prev = &*std::prev(Return->getIterator());
+  auto *Intr = dyn_cast<IntrinsicInst>(Prev);
+  if (!Intr)
+    return;
+  if (Intr->getIntrinsicID() != Intrinsic::ret_popless)
+    return;
+  Intr->eraseFromParent();
+}
+
 /// Clone the body of the original function into a resume function of
 /// some sort.
 void CoroCloner::create() {
@@ -1125,8 +1137,10 @@ void CoroCloner::create() {
   case coro::ABI::RetconOnce:
   case coro::ABI::RetconOnceDynamic:
     // Remove old returns.
-    for (ReturnInst *Return : Returns)
+    for (ReturnInst *Return : Returns) {
+      eraseIntrinsicRetPoplessBefore(Return);
       changeToUnreachable(Return);
+    }
     break;
 
   // With multi-suspend continuations, we'll already have eliminated the

llvm/test/Transforms/Coroutines/coro-retcon-once-dynamic-nocleanup.ll

@@ -0,0 +1,65 @@
+; RUN: opt < %s -passes='module(coro-early),cgscc(coro-split)' -S | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "arm64-apple-macos99.99"
+
+
+@func_cfp = constant <{ i32, i32 }>
+  <{ i32 trunc (
+       i64 sub (
+         i64 ptrtoint (ptr @func to i64),
+         i64 ptrtoint (ptr getelementptr inbounds (<{ i32, i32 }>, ptr @func_cfp, i32 0, i32 1) to i64)
+       )
+     to i32),
+     i32 64
+}>
+
+
+%func_int = type <{ i64 }>
+%func_obj = type <{ %func_int, ptr }>
+%func_guts = type <{ %func_obj }>
+%func_impl = type <{ %func_guts }>
+%func_self = type <{ %func_impl }>
+
+declare swiftcorocc void @func_continuation_prototype(ptr noalias, ptr)
+
+; CHECK-LABEL: @func.resume.0(
+; CHECK-SAME:      ptr noalias %0, 
+; CHECK-SAME:      ptr %1
+; CHECK-SAME:  ) {
+; CHECK:       coro.return.popless:
+; CHECK-NEXT:    unreachable
+; CHECK:       coro.return.normal:
+; CHECK-NEXT:    unreachable
+; CHECK:       }
+
+define swiftcorocc { ptr, ptr } @func(ptr noalias %buffer, ptr %allocator, ptr nocapture swiftself dereferenceable(16) %2) {
+entry:
+  %3 = call token @llvm.coro.id.retcon.once.dynamic(
+    i32 -1, 
+    i32 16,
+    ptr @func_cfp,
+    ptr %allocator,
+    ptr %buffer,
+    ptr @func_continuation_prototype,
+    ptr @allocate, 
+    ptr @deallocate
+  )
+  %handle = call ptr @llvm.coro.begin(token %3, ptr null)
+  %yielded = getelementptr inbounds %func_self, ptr %2, i32 0, i32 0
+  call ptr (...) @llvm.coro.suspend.retcon.p0(ptr %yielded)
+  br i1 false, label %unwind, label %normal
+
+normal:
+  br label %coro.end
+
+unwind:
+  br label %coro.end
+
+coro.end:
+  %8 = call i1 @llvm.coro.end(ptr %handle, i1 false, token none)
+  unreachable
+}
+
+declare swiftcorocc noalias ptr @allocate(i32 %size)
+declare void @deallocate(ptr %ptr)