Revert 189756 for now, it doesn't match what rdar://14871821 really wants.

What we really want is to enable Swift by default for *v7s triples (and there already seems to be some logic which attempts to do that). In that case the iOS version doesn't matter. 

llvm-svn: 189763
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index a8e62e5..3111f5e 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -133,13 +133,8 @@
 }
 
 void ARMSubtarget::resetSubtargetFeatures(StringRef CPU, StringRef FS) {
-  if (CPUString.empty()) {
-    if (isTargetIOS() && !getTargetTriple().isOSVersionLT(6))
-      // Default to Swift for iOS 6 or later versions.
-      CPUString = "swift";
-    else
-      CPUString = "generic";
-  }
+  if (CPUString.empty())
+    CPUString = "generic";
 
   // Insert the architecture feature derived from the target triple into the
   // feature string. This is important for setting features that are implied