[clang] [llvm] [RFC][Coroutines] Implement HALO for coroutines that flow off final suspend (PR #185336)

[Weibo He via llvm-commits]

================
@@ -1169,6 +1171,47 @@ Example (standard deallocation functions):
     call void @free(ptr %mem)
     ret void
 
+.. _coro.dead:
+
+'llvm.coro.dead' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+::
+
+  declare void @llvm.coro.dead(ptr <frame>)
+
+Overview:
+"""""""""
+
+The '``llvm.coro.dead``' intrinsic is an optimization hint to help Heap Allocation eLision Optimization(HALO).
----------------
NewSigma wrote:

Done

https://github.com/llvm/llvm-project/pull/185336