diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index cd4be2da094..7ae43fa789a 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -177,6 +177,8 @@ namespace llvm {
       CR6SET,
       CR6UNSET,
 
+      /// GPRC = address of _GLOBAL_OFFSET_TABLE_. Used by initial-exec TLS
+      /// on PPC32.
       PPC32_GOT,
 
       /// G8RC = ADDIS_GOT_TPREL_HA %X2, Symbol - Used by the initial-exec