Index: tools/llvm-cov/CodeCoverage.cpp
===================================================================
--- tools/llvm-cov/CodeCoverage.cpp
+++ tools/llvm-cov/CodeCoverage.cpp
@@ -1039,8 +1039,6 @@
     Exporter = llvm::make_unique<CoverageExporterLcov>(*Coverage.get(),
                                                        ViewOpts, outs());
     break;
-  default:
-    llvm_unreachable("Unknown coverage output format!");
   }
 
   if (SourceFiles.empty())