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Re: Architecture baseline for Forky



Hi,

On 10/27/25 9:15 AM, Jan-Daniel Kaplanski wrote:

Besides, the armhf baseline of armv7-a+fp aligns with the Cortex-A8 from 2005[2]. I highly doubt that archaic architecture has a lot of users besides SBCs up to the generation of RPi 2 and legacy embedded systems that are likely EOL too. Especially since aarch64 came in 2012 with armv8-a on the Cortex-A53/A57[3][4].

It makes sense to base the support on whether dropping older platforms actually gains something tangible. This was true for i386 .. i686, as we gained enough extra registers that -fPIC no longer incurred a 5% performance penalty, but the differences between iterations of other architectures are a lot smaller.

Newer machines might have a better vector unit, but this does not make a lot of difference outside of a bunch of mostly scientific applications that already select an appropriate computation kernel at runtime, and differences in instruction scheduling are better handled by assuming a way newer-than-baseline model for -mtune=.

That said, it would be nice to have a way to crossgrade architectures when the ABI is compatible, that would allow us to just create ports for older architectures, and shunt people over.

   Simon


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