Speed up genattrtab

[Michael Matz]

Hi,

On Wed, 16 Jun 2010, Nathan Froyd wrote:

> 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. Â But if some easy Makefile hackery would help some developers,
> > > I'd still argue we should do it. Â 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?

Because that's the definition of bootstrapping.  Either we bootstrap, or 
we don't.  It doesn't make sense to bootstrap only half the sources.


Ciao,
Michael.