[Cloning] cloneLoopWithPreheader(): add assert to ensure no sub-loops

Summary:
cloneLoopWithPreheader() does not update LoopInfo for sub-loop of
the original loop being cloned. Add assert to ensure no sub-loops for loop being cloned.

Reviewers: anemet, ashutosh.nema, hfinkel

Subscribers: mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D15922

llvm-svn: 267671

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index f2d929f..c8d1212 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -672,6 +672,8 @@ Loop *llvm::cloneLoopWithPreheader(BasicBlock *Before, BasicBlock *LoopDomBB,
                                    const Twine &NameSuffix, LoopInfo *LI,
                                    DominatorTree *DT,
                                    SmallVectorImpl<BasicBlock *> &Blocks) {
+  assert(OrigLoop->getSubLoops().empty() && 
+         "Loop to be cloned cannot have inner loop");
   Function *F = OrigLoop->getHeader()->getParent();
   Loop *ParentLoop = OrigLoop->getParentLoop();