[xxpor]

I'd think the issue would be more build infra, every new variant means you have to build the world again

[jiggawatts]

Again, compute is surprisingly cheap these days.

Work out what it would cost to compile - say - a terabyte of C code at typical cloud spot prices.

A large VM with 128 cores can compile the 100 MB Linux kernel source tree in about 30 seconds. So… 200 MB/minute or 12 GB/hour. This would take 80 hours for a terabyte.

A 120 core AMD server is about 50c per hour on Azure (Linux spot pricing).

So… about $40 to compile an entire distro. Not exactly breaking the bank.

[xxpor]

you'd have to separate out compiling and linking at a bare minimum to get even a semi accurate model. plus a lot of userspace is c++, which is much, much slower.

[kergonath]

Yes. Also, test it.

[jiggawatts]

That can also be largely automated.

[brucethemoose2]

LTO does rarely break things in hard to detect ways, but I have never heard of a -march x86 compilation bug.