[FuzzMutate] Correctly split landingpad blocks

Differential Revision: https://reviews.llvm.org/D41112

llvm-svn: 320571

1 files changed, 7 insertions, 2 deletions

diff --git a/llvm/lib/FuzzMutate/Operations.cpp b/llvm/lib/FuzzMutate/Operations.cpp
index 92993480215..b842f6d64fb 100644
--- a/llvm/lib/FuzzMutate/Operations.cpp
+++ b/llvm/lib/FuzzMutate/Operations.cpp
@@ -142,9 +142,14 @@ OpDescriptor llvm::fuzzerop::splitBlockDescriptor(unsigned Weight) {
   auto buildSplitBlock = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
     BasicBlock *Block = Inst->getParent();
     BasicBlock *Next = Block->splitBasicBlock(Inst, "BB");
+
+    // If it was an exception handling block, we are done.
+    if (Block->isEHPad())
+      return nullptr;
+
+    // Loop back on this block by replacing the unconditional forward branch
+    // with a conditional with a backedge.
     if (Block != &Block->getParent()->getEntryBlock()) {
-      // Loop back on this block by replacing the unconditional forward branch
-      // with a conditional with a backedge.
       BranchInst::Create(Block, Next, Srcs[0], Block->getTerminator());
       Block->getTerminator()->eraseFromParent();