[llvm] r278883 - Scalar: Avoid dereferencing end() in InductiveRangeCheckElimination

[Duncan P. N. Exon Smith via llvm-commits]

Author: dexonsmith
Date: Tue Aug 16 20:16:17 2016
New Revision: 278883

URL: http://llvm.org/viewvc/llvm-project?rev=278883&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp?rev=278883&r1=278882&r2=278883&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp Tue Aug 16 20:16:17 2016
@@ -1042,11 +1042,11 @@ LoopConstrainer::RewrittenRangeInfo Loop
 
   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;