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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156167 91177308-0d34-0410-b5e6-96231b3b80d8

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();