Scalar: Avoid dereferencing end() in InductiveRangeCheckElimination

BasicBlock::Create isn't designed to take iterators (which might be
end()), but pointers (which might be nullptr).  Fix the UB that was
converting end() to a BasicBlock* by calling BasicBlock::getNextNode()
in the first place.

llvm-svn: 278883

diff --git a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
index 148f348..9297eb3 100644 (file)
--- a/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
@@ -1042,11 +1042,11 @@ LoopConstrainer::RewrittenRangeInfo LoopConstrainer::changeIterationSpaceEnd(
 
   RewrittenRangeInfo RRI;
 
-  auto BBInsertLocation = std::next(Function::iterator(LS.Latch));
+  BasicBlock *BBInsertLocation = LS.Latch->getNextNode();
   RRI.ExitSelector = BasicBlock::Create(Ctx, Twine(LS.Tag) + ".exit.selector",
-                                        &F, &*BBInsertLocation);
+                                        &F, BBInsertLocation);
   RRI.PseudoExit = BasicBlock::Create(Ctx, Twine(LS.Tag) + ".pseudo.exit", &F,
-                                      &*BBInsertLocation);
+                                      BBInsertLocation);
 
   BranchInst *PreheaderJump = cast<BranchInst>(Preheader->getTerminator());
   bool Increasing = LS.IndVarIncreasing;