diff --git a/dmd/mars.c b/dmd/mars.c
index 4b00ad07..85a1c1e7 100644
--- a/dmd/mars.c
+++ b/dmd/mars.c
@@ -341,6 +341,8 @@ int main(int argc, char *argv[])
 #error
 #endif /* linux */
 
+    assert(global.params.os != OSinvalid);
+
     //VersionCondition::addPredefinedGlobalIdent("D_Bits");
     VersionCondition::addPredefinedGlobalIdent("all");
 
@@ -767,6 +769,8 @@ int main(int argc, char *argv[])
         assert(0 && "Invalid arch");
     }
 
+    assert(global.params.cpu != ARCHinvalid);
+
     if (allowForceEndianness && global.params.forceBE) {
         VersionCondition::addPredefinedGlobalIdent("BigEndian");
         global.params.isLE = false;
diff --git a/dmd/mars.h b/dmd/mars.h
index d224bef9..5d50b61b 100644
--- a/dmd/mars.h
+++ b/dmd/mars.h
@@ -40,6 +40,7 @@ struct Array;
 // LLVMDC
 enum ARCH
 {
+    ARCHinvalid,
     ARCHx86,
     ARCHx86_64,
     ARCHppc,
@@ -48,6 +49,7 @@ enum ARCH
 
 enum OS
 {
+    OSinvalid,
     OSLinux,
     OSWindows,
     OSMacOSX