Silence VC warning C4715: '`anonymous namespace'::getNativeVectorSizeForA VXABI' :

not all control paths return a value.

llvm-svn: 240389

clang/lib/CodeGen/TargetInfo.cpp

@@ -1408,6 +1408,7 @@ static unsigned getNativeVectorSizeForAVXABI(X86AVXABILevel AVXLevel) {
   case X86AVXABILevel::None:
     return 128;
   }
+  llvm_unreachable("Unknown AVXLevel");
 }
 
 /// X86_64ABIInfo - The X86_64 ABI information.