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Re: Speed up genattrtab
On Wed, Jun 16, 2010 at 09:15:39AM +0200, Richard Guenther wrote:
> On Tue, Jun 15, 2010 at 8:39 PM, Mark Mitchell <mark@codesourcery.com> wrote:
> > I certainly don't claim it's a general solution; at some point, if you
> > have enouh cores, the single core compiling insn-attrtab will dominate
> > anyhow. ?But if some easy Makefile hackery would help some developers,
> > I'd still argue we should do it. ?And I still have a hard time with a
> > change that's going to make the compiler slower in order to save a
> > minute or two during compiler builds, especially given that test cycles
> > are so much longer than build cycles.
>
> I think the makefile ordering is already good - it is just that genattrtab
> takes so much time that compiling insn-attrtab starts very late. Michael
> addresses this by speeding up genattrtab.
Pardon the dumb question here, but IIUC, we build insn-attrtab at each
stage. Why not just build it once for all stages? Do we gain anything
(besides less complicated Makefiles) by building it at every stage? I
realize that this is not quite as nice as cutting its build time by
90%+, but moving it earlier might hide the compilation latency just as
effectively.
-Nathan