diff --git a/lib/Transforms/Scalar/TailDuplication.cpp b/lib/Transforms/Scalar/TailDuplication.cpp index 9427fc664ad..688119805ac 100644 --- a/lib/Transforms/Scalar/TailDuplication.cpp +++ b/lib/Transforms/Scalar/TailDuplication.cpp @@ -12,6 +12,7 @@ //===----------------------------------------------------------------------===// #include "llvm/Transforms/Scalar.h" +#include "llvm/Constant.h" #include "llvm/Function.h" #include "llvm/iPHINode.h" #include "llvm/iTerminators.h" @@ -268,8 +269,10 @@ Value *TailDup::GetValueInBlock(BasicBlock *BB, Value *OrigVal, ValueHolder &BBVal = ValueMap[BB]; if (BBVal) return BBVal; // Value already computed for this block? - assert(pred_begin(BB) != pred_end(BB) && - "Propagating PHI nodes to unreachable blocks?"); + // If this block has no predecessors, then it must be unreachable, thus, it + // doesn't matter which value we use. + if (pred_begin(BB) == pred_end(BB)) + return BBVal = Constant::getNullValue(OrigVal->getType()); // If there is no value already available in this basic block, we need to // either reuse a value from an incoming, dominating, basic block, or we need