[lib/LTO] Add an assertion to catch invalid opt levels.

llvm-svn: 279823

diff --git a/llvm/lib/LTO/LTOCodeGenerator.cpp b/llvm/lib/LTO/LTOCodeGenerator.cpp
index 1120ad8..7f3d30a 100644 (file)
--- a/llvm/lib/LTO/LTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -185,17 +185,18 @@ void LTOCodeGenerator::setOptLevel(unsigned Level) {
   switch (OptLevel) {
   case 0:
     CGOptLevel = CodeGenOpt::None;
-    break;
+    return;
   case 1:
     CGOptLevel = CodeGenOpt::Less;
-    break;
+    return;
   case 2:
     CGOptLevel = CodeGenOpt::Default;
-    break;
+    return;
   case 3:
     CGOptLevel = CodeGenOpt::Aggressive;
-    break;
+    return;
   }
+  llvm_unreachable("Unknown optimization level!");
 }
 
 bool LTOCodeGenerator::writeMergedModules(const char *Path) {