[llvm] [NFC][Coroutines] Remove redundant checks for replacing PrepareFns (PR #98392)

[Yuxuan Chen via llvm-commits]

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@@ -2108,12 +2108,6 @@ PreservedAnalyses CoroSplitPass::run(LazyCallGraph::SCC &C,
   if (Coroutines.empty() && PrepareFns.empty())
     return PreservedAnalyses::all();
 
-  if (Coroutines.empty()) {
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yuxuanchen1997 wrote:

Oh sorry. I meant L2118 here. `for (LazyCallGraph::Node *N : Coroutines) {`

With and without this block, the executed logic is identical. With this block, this PrepareFns gets replaced with `replaceAllPrepares` on L2113. Without this block, if the Coroutines collection happens to be empty, it goes to the L2118 loop without any iteration, it goes to L2146 to perform the same logic. 

https://github.com/llvm/llvm-project/pull/98392