Revert CPU detection code to return "generic" instead of an empty string in case

of failure. The x86 target didn't like empty cpu names and broke x86 tests on
non-x86 buildbots.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89111 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/CommandLine.cpp

@@ -1154,7 +1154,7 @@ public:
     OS << " with assertions";
 #endif
     std::string CPU = sys::getHostCPUName();
-    if (CPU.empty()) CPU = "(unknown)";
+    if (CPU == "generic") CPU = "(unknown)";
     OS << ".\n"
        << "  Built " << __DATE__ << " (" << __TIME__ << ").\n"
        << "  Host: " << sys::getHostTriple() << '\n'