[llvm] [JumpThreading] Thread over BB with only an unconditional branch (PR #86312)

[Yingwei Zheng via llvm-commits]

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@@ -1013,12 +1013,14 @@ CanRedirectPredsOfEmptyBBToSucc(BasicBlock *BB, BasicBlock *Succ,
                                 const SmallPtrSetImpl<BasicBlock *> &SuccPreds,
                                 BasicBlock *&CommonPred) {
 
-  // There must be phis in BB, otherwise BB will be merged into Succ directly
-  if (BB->phis().empty() || Succ->phis().empty())
+  // Only handle the nontrivial case. Assume we need to update the phi of succ
+  // here.
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dtcxzyw wrote:

I think the original comment is easier to understand than this one.

https://github.com/llvm/llvm-project/pull/86312