[clang] [llvm] [coroutine] Implement llvm.coro.await.suspend intrinsic (PR #79712)

[Chuanqi Xu via cfe-commits]

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@@ -79,6 +79,73 @@ using namespace llvm;
 
 namespace {
 
+// Created on demand if the coro-early pass has work to do.
+class Lowerer : public coro::LowererBase {
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ChuanqiXu9 wrote:

Why do we need to inherit `coro::LowererBase`? Can't we make it directly in a function?

https://github.com/llvm/llvm-project/pull/79712