[PATCH] Refactor ARM subarchitecture parsing.

[Renato Golin]

Hi Gabor,

Thanks for working on this, looks a lot better! I think we have tests for all of them, and I assume they're all passing. 

With the changes below, LGTM.

cheers,
--renato

================
Comment at: include/llvm/ADT/Triple.h:81
@@ -80,1 +80,3 @@
   };
+  enum SubArchType {
+    NoSubArch,
----------------
I'd number them in sequential order, so you can do tricks like Arch > v5.

================
Comment at: lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp:163
@@ +162,3 @@
+    break;
+  case Triple::v4t:
+    ARMArchFeature = "+v4t";
----------------
you could add the NoSubArch here, as a default.

http://reviews.llvm.org/D4375