[CloneFunction] Support BB == PredBB in DuplicateInstructionsInSplit.

In case PredBB == BB and StopAt == BB's terminator, StopAt != &*BI will
fail, because BB's terminator instruction gets replaced.

By using BB.getTerminator() we get the current terminator which we can use
to compare.

Reviewers: sanjoy, anna, reames

Reviewed By: anna

Differential Revision: https://reviews.llvm.org/D43822

llvm-svn: 326779

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 16af2c7b808..3bc178ec88b 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -811,7 +811,9 @@ llvm::DuplicateInstructionsInSplitBetween(BasicBlock *BB, BasicBlock *PredBB,
 
   // Clone the non-phi instructions of BB into NewBB, keeping track of the
   // mapping and using it to remap operands in the cloned instructions.
-  for (; StopAt != &*BI; ++BI) {
+  // Stop once we see the terminator too. This covers the case where BB's
+  // terminator gets replaced and StopAt == BB's terminator.
+  for (; StopAt != &*BI && BB->getTerminator() != &*BI; ++BI) {
     Instruction *New = BI->clone();
     New->setName(BI->getName());
     New->insertBefore(NewTerm);