Rather than trying to gracefully handle input sequences with repeated

blocks, assert that this doesn't happen. We don't want to bother trying
to support this call pattern as it isn't necessary.

llvm-svn: 156167

llvm/lib/Transforms/Utils/CodeExtractor.cpp

@@ -74,7 +74,7 @@ buildExtractionBlockSet(ArrayRef<BasicBlock *> BBs) {
   for (ArrayRef<BasicBlock *>::iterator I = BBs.begin(), E = BBs.end();
        I != E; ++I) {
     if (!Result.insert(*I))
-      continue;
+      llvm_unreachable("Repeated basic blocks in extraction input");
 
     if (!isBlockValidForExtraction(**I)) {
       Result.clear();