On 10/4/19 9:01 AM, Richard Sandiford wrote:
> I'd like to use CONSTEXPR to get static initialisation of some
> aarch64-specific variables. This obviously means that cross toolchains
> built with old compilers won't benefit, but I hope toolchains built with
> newer compilers are faster for other reasons too. :-)
>
> The variables in question have scalar_int_mode fields, so I first
> needed to make the machine_mode stuff more constexpr-friendly.
> This patch therefore adds CONSTEXPR to constructors and operators in
> machmode.h, excluding the controversial constexpr-resistant "() {}"
> constructors, which would become "= default" if we required C++11.
>
> Some of the other routines could potentially be constexpr too,
> but that can be done on an as-needed basis.
>
> Tested on aarch64-linux-gnu, with and without the follow-on changes.
> OK to install?
>
> Richard
>
>
> 2019-10-04 Richard Sandiford <[email protected]>
>
> gcc/
> * machmode.h (opt_mode): Mark constructors with CONSTEXPR.
> (pod_mode): Mark operators likewise.
> (scalar_int_mode): Mark non-default constructors and
> operators with CONSTEXPR.
> (scalar_float_mode, scalar_mode, complex_mode): Likewise.
> (fixed_size_mode): Likewise.
Given that we've got the necessary magic in ansidecl.h and have already
started using constexpr elsewhere (bitmap, vec) I think this has to be
considered OK regardless of any policies we have WRT C++11 features.
So OK as would be the introduction of CONSTEXPR elsewhere.
Jeff
