[clang] [llvm] [coro] Lower `llvm.coro.await.suspend.handle` to resume with tail call (PR #89751)

[via cfe-commits]

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@@ -206,14 +210,37 @@ static void lowerAwaitSuspend(IRBuilder<> &Builder, CoroAwaitSuspendInst *CB) {
     llvm_unreachable("Unexpected coro_await_suspend invocation method");
   }
 
+  if (CB->getCalledFunction()->getIntrinsicID() ==
+      Intrinsic::coro_await_suspend_handle) {
+    // Follow the await_suspend by a lowered resume call to the returned
+    // coroutine.
+    if (auto *Invoke = dyn_cast<InvokeInst>(CB))
+      Builder.SetInsertPoint(Invoke->getNormalDest()->getFirstInsertionPt());
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zmodem wrote:

In that case the Builder's insert point is already in the right place.

That's what the "Follow ..." comment refers to. In both cases, we want to follow the await_suspend. It's only for an invoke that we need to jump to the next block.

https://github.com/llvm/llvm-project/pull/89751