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llvm-svn: 139699
diff --git a/llvm/lib/Target/Mips/MipsSubtarget.h b/llvm/lib/Target/Mips/MipsSubtarget.h
index 3193369..77bd31c 100644
--- a/llvm/lib/Target/Mips/MipsSubtarget.h
+++ b/llvm/lib/Target/Mips/MipsSubtarget.h
@@ -27,6 +27,7 @@
 class MipsSubtarget : public MipsGenSubtargetInfo {
 
 public:
+  // NOTE: O64 will not be supported.
   enum MipsABIEnum {
     O32, N32, N64, EABI
   };