Break seems serve better here.

llvm-svn: 305150
diff --git a/llvm/tools/llvm-stress/llvm-stress.cpp b/llvm/tools/llvm-stress/llvm-stress.cpp
index f1cdc5f..9696dec 100644
--- a/llvm/tools/llvm-stress/llvm-stress.cpp
+++ b/llvm/tools/llvm-stress/llvm-stress.cpp
@@ -382,7 +382,7 @@
       switch (Ran->Rand() % 2) {
       case 0: if (Ty->getScalarType()->isIntegerTy())
                 return PT->push_back(ConstantVector::getAllOnesValue(Ty));
-              llvm_unreachable("Unexpected state");
+              break;
       case 1: if (Ty->getScalarType()->isIntegerTy())
                 return PT->push_back(ConstantVector::getNullValue(Ty));
       }