Switch assert(0/false) llvm_unreachable.

llvm-svn: 140367
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index e6992613..03d06e6 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1164,7 +1164,7 @@
   if (const Arg *A = Args.getLastArg(OPT_Action_Group)) {
     switch (A->getOption().getID()) {
     default:
-      assert(0 && "Invalid option in group!");
+      llvm_unreachable("Invalid option in group!");
     case OPT_ast_dump:
       Opts.ProgramAction = frontend::ASTDump; break;
     case OPT_ast_dump_xml:
@@ -1457,7 +1457,7 @@
     case IK_None:
     case IK_AST:
     case IK_LLVM_IR:
-      assert(0 && "Invalid input kind!");
+      llvm_unreachable("Invalid input kind!");
     case IK_OpenCL:
       LangStd = LangStandard::lang_opencl;
       break;