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Re: Speed up genattrtab
On Jun 16, 2010, at 6:37 AM, Nathan Froyd <froydnj@codesourcery.com> wrote:
> 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.
That is true, unless there are bugs. We compile with gcc , and then test to ensure there are no bugs. In this fashion, 100% of the source that is compiled, is compiled with gcc, the very definition of bootstrap. People that want more speed at the expense of testing, don't bootstrap.