On Wed, Sep 25, 2019 at 9:14 AM Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > > config ARCH_SUPPORTS_INT128 > bool > + depends on !$(cc-option,-D__SIZEOF_INT128__=0) Hmm. Does this actually work? If that "depends on" now ends up being 'n', afaik the people who _enable_ it just do a select ARCH_SUPPORTS_INT128 and now you'll end up with the Kconfig erroring out with WARNING: unmet direct dependencies detected for ARCH_SUPPORTS_INT128 and then you end up with CONFIG_ARCH_SUPPORTS_INT128 anyway, instead of the behavior you _want_ to get, which is to not get that CONFIG defined at all. So I heartily agree with your intent, but I don't think that model works. I think you need to change the cases that currently do select ARCH_SUPPORTS_INT128 to instead have that cc-option test. And take all the above with a pinch of salt. Maybe what you are doing works, and I am just missing some piece of the puzzle. But I _think_ it's broken, and you didn't test with a compiler that doesn't support that thing properly. Linus