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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37741 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/MRegisterInfo.h b/include/llvm/Target/MRegisterInfo.h
index d6d3fb4..ecfe1ec 100644
--- a/include/llvm/Target/MRegisterInfo.h
+++ b/include/llvm/Target/MRegisterInfo.h
@@ -40,9 +40,11 @@
/// Registers that this does not apply to simply should set this to null.
/// The SubRegs field is a zero terminated array of registers that are
/// sub-registers of the specific register, e.g. AL, AH are sub-registers of AX.
-/// The SuperRegs field is a zero terminated array of registers that are
-/// super-registers of the specific register, e.g. RAX, EAX, are super-registers
-/// of AX.
+/// The ImmsubRegs field is a subset of SubRegs. It includes only the immediate
+/// sub-registers. e.g. EAX has only one immediate sub-register of AX, not AH,
+/// AL which are immediate sub-registers of AX. The SuperRegs field is a zero
+/// terminated array of registers that are super-registers of the specific
+/// register, e.g. RAX, EAX, are super-registers of AX.
///
struct TargetRegisterDesc {
const char *Name; // Assembly language name for the register