[Bug target/88952] The asm operator modifiers for rs6000 should be documented like they are for x86

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88952

Segher Boessenkool <segher at gcc dot gnu.org> changed:

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                 CC|                            |segher at gcc dot gnu.org

--- Comment #12 from Segher Boessenkool <segher at gcc dot gnu.org> ---
How old is your GCC?  I don't have anything older than 4.6 handy, and
that uses even-odd register pairs already (in big-endian mode, and the
other way around in little-endian mode) .  4.2 is over ten years old;
the oldest GCC still supported is GCC 7.

Being able to pass double-integer values to inline asm is a useful
feature.  There are many other much more surprising gotchas when you
make errors or typos in asm stuff.

But yup, we should document the output modifiers that we want people
to use, just like those constraints that we want people to use.  Those
that are for GCC internal use only should not be documented.