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Comment by fooker | Hacker News Reader

>Itanium wasn’t a turd

It required immense multi-year efforts from compiler teams to get passable performance with Itanium. And passable wasn't good enough.

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The IA-64 architecture had too much granularity of control dropped into software. Thus, reliable compiler designs were much more difficult to build.

It wasn't a bad chip, but like Cell or modern Dojo tiles most people couldn't run it without understanding parallelism and core metastability.

amd64 wasn't initially perfect either, but was accessible for mere mortals. =3

Wasn't the only compiler that produced code worth anything for Itanium the paid one from Intel? I seem to recall complaining about it on the GCC lists.

I lost track of it but HP, as co-architects, had its own compiler team working on it. I think SGI also had efforts to target ia64 as well. But the EPIC (Explicitly Parallel Instruction Computing) didn't really catch on. VLIW would need recompilation on each new chip but EPIC promised it would still run.

https://en.wikipedia.org/wiki/Explicitly_parallel_instructio...

In the compiler world, these HP compiler folks are leading compiler teams/orgs at ~all the tech companies now, while almost none of the Intel compiler people seem to be around.

Are you sure about that? If my memory serves, a lot of the Intel compiler people were transferred from HP? At least in the Fortran world, the Fortran frontend for the Intel compiler traces it's lineage back to DEC Fortran (for VAX and later Alpha) -> Compaq Visual Fortran (for Windows) -> Intel Fortran.

Yes, SGI sold quite a lot of high-end IA-64 machines for HPCs, e.g. https://en.wikipedia.org/wiki/SGI_Altix

NOTHING produced good code for the original Itanium which is why they switched gears REALLY early on.

Intel first publicly mentioned Poulson all the way back in 2005 just FOUR years after the original chip was launched. Poulson was basically a traditional out-of-order CPU core that even had hyperthreading[0]. They knew really early on that the designs just weren't that good. This shouldn't have been a surprise to Intel as they'd already made a VLIW CPU in the 90s (i860) that failed spectacularly.

[0]https://www.realworldtech.com/poulson/

Even the i860 found more usage as a specialized CPU than the Itanium. The original Nextcube had an optional video card that used an i860 dedicated to graphics.

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