[PATCH] Allow case-insensitive comparisons of register names by implementing CASE_INSENSITIVE_REGISTER_NAMES PR target/70320

[Richard Sandiford]

Segher Boessenkool <segher@kernel.crashing.org> writes:
> On Fri, Jul 19, 2019 at 10:55:59AM +0100, Richard Sandiford wrote:
>> Jozef Lawrynowicz <jozef.l@mittosystems.com> writes:
>> > Is the downside of this macro implementation compared to a DEFHOOKPOD mainly
>> > just the maintainability/readability of the added code?
>> 
>> Macros are essentially the "old way" and target hooks the "new way".
>> The decision was made a long time ago to move away from macros where
>> possible.  TBH I no longer remember the reasons clearly, but I think
>> it was partly to avoid including so much target stuff in non-target
>> files, and partly in the hope that we might one day support multiple
>> targets in a single build.  Years later, we're not much closer to the
>> latter and I'm not sure it's a realistic goal.
>
> Macros also are hard to use: they do not follow the normal language rules,
> they just do text replacement (and C macros are terribly weak, at that).
> Some of this is made better by conventions like "always put all uses of
> macro parameters in parentheses", but that itself is an extra mental load
> to remember.
>
>> That said, there are some macros that are too compile-time sensitive
>> to be hooks or variables.  BITS_PER_UNIT is the most obvious example.
>
> Maybe C++ can help here?  Or maybe we can declare some hooks as inline
> functions somehow?

FWIW, I have a WIP patch that uses C++ here.  I expect people will
hate it :-)

Richard