Didn't they build the architecture and then chuck it?

Yes, called Seattle, in their codenames.

For a little while there was one partner who used it for Gluster ( or similar ) storage nodes.

It fit into the model of Arm processors that were performant enough to be the glue between hard disks or flash and a reasonably fast network. But after the PCI lanes were all dispatched there wasn't a lot of compute for applications on top.

I think it's this rumor: https://www.hardwareheaven.com/amd-is-preparing-an-arm-soc-f...

I think they grafted 4 and 8 cortex a57 in to a package and it didn’t seem to have much market interest.

I too have heard that they have their own ARM micro architecture project though

I could see AMD grafting an Arm front end onto Epyc.

If I were them I wouldn't even bother with anything pre-Arm v9. That's going to draw all the hype, especially when Apple announces the Arm v9-based M2 next year.

And then I'm sure most sheep-like OEMs will say "Oh, we want THAT, too. Where is it - we want it yesterday!" But AMD won't be able to provide one too soon, because they would've gone all in on Arm v8, and they'd want to squeeze at least a couple of generations out of that microarchitecture.

Something similar happened when Apple announced the first Armv8 processor and it took Qualcomm and all the rest 2 years to catch-up.

At the time of the intro of 64 bit ARM, the conventional wisdom was, "Pooh pooh, this'll just bloat your code and not offer any performance advantage whatsoever. How pointlessly stupid!"

The problem is that ARMv9, as I type this, is not available. Perhaps ARM holdings and/or NVidia are working on the ARMv9 instruction set, and there has been a lot of speculation about what ARMv9 will be, but so far nothing concrete. [1]

ARMv8 (i.e. 64-bit ARM), of course, has been around for a while now.

[1] Keep in mind that anything on Reddit not confirmed elsewhere is very likely either wild speculation or made up fiction.

Apple is usually the first to ship ARM designs. I think they are the only ARMv8.5 implementation at the moment.