jit status in 4.2 (was Re: More everything into the octave namespace)

[Mike Miller]

On Tue, Sep 13, 2016 at 10:47:47 -0700, chechu wrote:
> Good evening to everyone,

Please start a new thread instead of hijacking an existing thread, your
message has little to do with the thread you posted on.

> Those last days the first RC to 4.2 is being released. Maybe I got lost on
> the octave-mantainers list that summer.
> We have tried to get the 4.2.0 version work as the previous ones and we are
> facing problems getting the JIT compiler to be enabled. As we have realised,
> there were changes on its behaviour, getting its infraestructure inside
> namespaces, as many other core parts.
> 
> Is it still posible to use the JIT compiler? We have tried with the MXE LLVM
> 3.3 and the newer LLVM 3.8 and both of them give the same errors at
> compilation time. 

I don't know whether Octave 4.2 will compile with LLVM 3.3, I think many
of the core developers don't have access to that old version of LLVM any
longer (I know I don't).

I know that Octave will definitely *not* compile with LLVM 3.5 or newer.

The interface to LLVM simply became unmaintainable and we have no one
interested enough to continue to make it work across multiple
incompatible versions of the LLVM library.

> That linux environment, config and dependencies works on 4.0.3 last stable
> release.
> Maybe the JIT compiler is not usefull for more complicated executions as the
> Matlab JIT counterpart, but for us it was always enabled.
> There is any prevision of when will it be reenabled? Or it will be
> depreciated?

If you or someone would like to fix it so that it works again on some
version of LLVM, such a patch might be reviewed for the next release.

There is no active development being done to make JIT work again with
LLVM or with any other library. There has been some talk about trying to
work with libgccjit as an alternative/replacement.

-- 
mike