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.

llvm-svn: 89111

llvm/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'

llvm/lib/System/Host.cpp

@@ -249,7 +249,7 @@ std::string sys::getHostCPUName() {
     }
 
     default:
-      return "";
+      return "generic";
     }
   } else if (memcmp(text.c, "AuthenticAMD", 12) == 0) {
     // FIXME: this poorly matches the generated SubtargetFeatureKV table.  There
@@ -289,10 +289,10 @@ std::string sys::getHostCPUName() {
       case 16:
         return "amdfam10";
     default:
-      return "";
+      return "generic";
     }
   }
 #endif
 
-  return "";
+  return "generic";
 }