Fix 12513: Loop unrolling breaks with indirect branches.

Take this opportunity to generalize the indirectbr bailout logic for
loop transformations. CFG transformations will never get indirectbr
right, and there's no point trying.

llvm-svn: 154386

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 512b6895011..e15497a77ae 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -149,6 +149,12 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     return false;
   }
 
+  // Loops with indirectbr cannot be cloned.
+  if (!L->isSafeToClone()) {
+    DEBUG(dbgs() << "  Can't unroll; Loop body cannot be cloned.\n");
+    return false;
+  }
+
   BasicBlock *Header = L->getHeader();
   BranchInst *BI = dyn_cast<BranchInst>(LatchBlock->getTerminator());