Index: driver/cfa.cc
===================================================================
--- driver/cfa.cc	(revision 41cca44b5b36b35c27f252878c7488107149c20a)
+++ driver/cfa.cc	(revision 13a984c6e9ba80e71a8c43f02a81da9e4c332f1e)
@@ -359,7 +359,12 @@
 
 	string arch = m32 ? CFA_32_CPU : (m64 ? CFA_64_CPU : CFA_DEFAULT_CPU);
-	if ( ! m32 && ! m64 && arch == "x86" ) {			// no override and 32-bit architecture
-		args[nargs] = "-m32";
-		nargs += 1;
+	if ( ! m32 && ! m64 ) {
+		if ( arch == "x86" ) {
+			args[nargs] = "-m32";
+			nargs += 1;
+		} else if ( arch == "x64" ) {
+			args[nargs] = "-m64";
+			nargs += 1;
+		}  // if
 	} // if
 	const char * config = debug ? "debug": "nodebug";