[Haskell-cafe] llvm is generating invalid instructions (problem with autovectorization?)

[Carter Schonwald]

Is this on a Mac that is using gcc4.2?  The older GCC assembler stuff
doesn't understand simd.

On Wednesday, May 21, 2014, Geoffrey Mainland <mainland at apeiron.net> wrote:

> Perhaps your installed version of binutils does not support the sarxq
> instruction?
>
> You can ask GHC to pass flags to llc and friends:
>
>
> http://www.haskell.org/ghc/docs/7.8.2/html/users_guide/options-phases.html#forcing-options-through
>
> Best,
> Geoff
>
> On 05/21/2014 06:50 PM, Mike Izbicki wrote:
> > I have some code* that is causing llvm to throw a fit.  In particular,
> > I get (compiling with GHC 7.8 and llvm 3.4):
> >
> >     /tmp/ghc1685_0/ghc1685_5.bc:150324:0:
> >          Error: no such instruction: `sarxq %rax,%rbx,%r14'
> >
> > Similar errors get repeated several thousand times, and it's always a
> > sarxq instruction.  Now, my code doesn't use any of the simd primops,
> > so the sarxq must be coming from llvm's autovectorization.  Is it
> > possible that somehow GHC's output bytecode could be responsible, or
> > is the problem more likely with llvm proper?  Is there any way I can
> > force GHC to pass flags to llvm so I can experiment with different
> > settings?
> >
> > Another clue that the cause might be in llvm's autovectorization is
> > that when I compile with llvm 3.0 (which does not support
> > autovectorization), there are no error messages.
> >
> > * I suspect my code is far too complicated for it to shed any light on
> > this question, but it's available at:
> >
> https://github.com/mikeizbicki/HLearn/tree/dev-7.8/src/examples/hlearn-allknn
> > If need be, I can create a minimal sample of code that causes the
> > error, but I don't want to go through the trouble if it's not needed.
> >
> >
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org <javascript:;>
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20140521/2f8589e6/attachment.html>