Re: LLVM as a gcc plugin?

[Chris Lattner <clattner at apple dot com>]

On Jun 3, 2009, at 11:59 PM, Miles Bader wrote:

> Chris Lattner <clattner@apple.com> writes:
> > > Some time ago, there was a discussion about integrating LLVM and GCC
> > > [1]. However, with plugin infrastructure in place, could LLVM be
> > > plugged into GCC as an additional optimization plugin?
> >
> > I'd love to see this, but I can't contribute to it directly.  I think
> > the plugin interfaces would need small extensions, but there are no
> > specific technical issues preventing it from happening.  LLVM has
> > certainly progressed a lot since that (really old) email went out :)
>
> Is there a description somewhere of areas where llvm is thought to do
> well compared to gcc, and maybe future plans for improvement?
>
> In the (limited) tests I've done, gcc [4.4, but 4.2 yields similar
> results] seems to do a lot better than llvm [2.5], but those were C++
> code and I wonder if llvm is currently concentrating on C?

LLVM has many capabilities and advantages that GCC doesn't (and is  
also missing some features and capabilities that GCC has), but it is  
also common to misconfigure it so that it isn't optimizing like it  
should.  It is pretty off topic for this list though, please ask on  
the llvmdev mailing list for more information.  Please send  
information about how you built llvm and what your machine  
configuration is,

Thanks,

-Chris