[brucehoult]

Well-known, yes, but fringe as in seldom seen.

Absolutely correct that mega-millions or billions went into it, both hardware and software, and that it FUD'ed many other ISAs to premature extinction.

It's not that hard to get an ISA into gcc and Linux -- you just need shipping hardware (or a convincing story that there will be) and someone to do the work. For example Andes (Taiwan) and C-Sky (China) both got their proprietary ISAs (nds32, c-sky) into GCC and the Linux kernel. And both switched to RISC-V not long after :_)

[epcoa]

Ok I’ll concede that’s a graveyard of obscurity in the gcc tree, but some group of people thought each one of those were worth the effort at some point, possibly delusionally. Do you need shipping hardware even? MMIX has a backend. Itanium doesn’t deserve this label though, shall it live forever in infamy.