Re: disallow big-endian on aarch64

On Thu, Oct 02, 2025 at 10:29:39PM +0200, Tomas Vondra wrote:
> I don't follow the reasoning. If there are no aarch64 platforms running
> in big-endian mode (at least not supported ones), then how would you
> even build Postgres in such environment?
> 
> Also, what's the benefit of disabling it? Is it about disabling
> something we can't meaningfully test (even though we still support other
> big-endian platforms, right?). Or does it affect the SIMD stuff somehow?

The benefit is that we can safely assume little-endian in AAarch64-specific
code, and on the off-chance that someone tries to build Postgres in an
AArch64/big-endian environment, we aren't pretending to support it.  I'd
expect this to affect almost nobody in practice, which is why I'm proposing
that we just disallow it completely.  As you noted, we can't meaningfully
test it, anyway.

I'm not proposing that we remove big-endian support from any other
platforms besides AArch64.

-- 
nathan