Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 docs/devel/decodetree.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/devel/decodetree.rst b/docs/devel/decodetree.rst
index d9be30b2db..62cb7f687c 100644
--- a/docs/devel/decodetree.rst
+++ b/docs/devel/decodetree.rst
@@ -69,6 +69,13 @@ with each of the fields being one of the member arguments.
 If ``!extern`` is specified, the backing structure is assumed
 to have been already declared, typically via a second decoder.
 
+Argument sets are useful when one wants to define helper functions
+for the translator functions that can perform operations on a common
+set of arguments.  This can ensure, for instance, that the ``AND``
+pattern and the ``OR`` pattern put their operands into the same named
+structure, so that a common ``gen_logic_insn`` may be able to handle
+the operations common between the two.
+
 Argument set examples::
 
   &reg3       ra rb rc
-- 
2.17.2

On 2/28/19 6:24 AM, Richard Henderson wrote:
> Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   docs/devel/decodetree.rst | 7 +++++++
>   1 file changed, 7 insertions(+)

Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>

Cheers,

Bastian