Speed up genattrtab

[Nathan Froyd]

On Wed, Jun 16, 2010 at 03:23:49PM +0200, Michael Matz wrote:
> On Wed, 16 Jun 2010, Nathan Froyd wrote:
> > On Wed, Jun 16, 2010 at 09:15:39AM +0200, Richard Guenther wrote:
> > > 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.

I'm not asking why we compile insn-attrtab at every stage, but why we
run genattrtab at every stage.  I understand that it's nice to compile
genattrtab at each stage for a little sanity checking, but the compiler
used to compile genattrtab should have no effect on the output of
genattrtab.

Or were you already responding to "why generate insn-attrtab at every
stage"?

-Nathan