Re: [PATCH] rs6000: Fix issue in specifying PTImode as an attribute [PR106895]

[Segher Boessenkool <segher@kernel.crashing.org>]

Hi!

On Fri, Feb 23, 2024 at 03:04:13PM +0530, jeevitha wrote:
> PTImode attribute assists in generating even/odd register pairs on 128 bits.

It is a mode, not an attribute.  Attributes are on declarations, while
modes are on a much more fundamental level (every value has a mode, in
GCC!)

> When the user specifies PTImode as an attribute, it breaks because there is no
> internal type to handle this mode . We have created a tree node with dummy type
> to handle PTImode.

You are talking about the mode attribute.  Aha.

This attribute says the mode of the datum is something specific; it is
the only way a user can specify the mode directly.  Not something you
want to use normally, but it's a nice escape hatch (like here).

> We are not documenting this dummy type since users are not
> allowed to use this type externally.

Not sure what this is meant to mean?  What does "allowed to" mean, even?
We do not forbid people from doing anything (we can discourage them
though).  Or dso you mean something just doesn't work?

> gcc/
> 	PR target/106895
> 	* config/rs6000/rs6000.h (enum rs6000_builtin_type_index): Add fields
> 	to hold PTImode type.

An enum does not have fields.  What do you actually mean?

> --- a/gcc/config/rs6000/rs6000.h
> +++ b/gcc/config/rs6000/rs6000.h
> @@ -2304,6 +2304,7 @@ enum rs6000_builtin_type_index
>    RS6000_BTI_ptr_vector_quad,
>    RS6000_BTI_ptr_long_long,
>    RS6000_BTI_ptr_long_long_unsigned,
> +  RS6000_BTI_PTI,

Please call it RS6000_BTI_INTPTI, to be more in line with the naming of
other things.

With that fixed it should be good.  Please repost with a good commit
comment and changelog :-)

Thanks,


Segher