Index: llvm/tools/llvm-reduce/deltas/ReduceBasicBlocks.cpp
===================================================================
--- llvm/tools/llvm-reduce/deltas/ReduceBasicBlocks.cpp
+++ llvm/tools/llvm-reduce/deltas/ReduceBasicBlocks.cpp
@@ -110,7 +110,7 @@
   SmallVector<BasicBlock *> BBsToDelete;
   for (auto &F : Program) {
     for (auto &BB : F) {
-      if (O.shouldKeep())
+      if (BB.isEntryBlock() || O.shouldKeep())
         BBsToKeep.insert(&BB);
       else {
         BBsToDelete.push_back(&BB);