Relax this condition.

Some passes require breaking critical edges before they're called. Don't
segfault because of that.

llvm-svn: 140196

llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp

@@ -178,8 +178,7 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
 
   // Splitting the critical edge to a landing pad block is non-trivial. Don't do
   // it in this generic function.
-  assert(!DestBB->isLandingPad() &&
-         "Cannot split critical edge to a landing pad block!");
+  if (DestBB->isLandingPad()) return 0;
 
   // Create a new basic block, linking it into the CFG.
   BasicBlock *NewBB = BasicBlock::Create(TI->getContext(),