[cfe-dev] Improving PCH build times by instantiating templates in the PCH

[Lubos Lunak via cfe-dev]

On Tuesday 14 of January 2020, Zachary Turner wrote:
> FWIW, I would really like to see this patch move forward as it has the
> potential to speed up precompiled headers quite significantly.
> our internal builds using clang-cl are about 3x slower than MSVC using PCH,
> and it's likely in large part due to this exact issue.

 You could try also using flags from https://reviews.llvm.org/D69778 , which I 
pushed yesterday. But I don't know if they'll make much of a difference 
without this main PCH patch, which given today's branching for 10.0 has 
missed the bus there I guess :( ?



> On Mon, Jan 13, 2020 at 2:11 PM Lubos Lunak via cfe-dev <
>
> cfe-dev at lists.llvm.org> wrote:
> >  Hello,
> >
> >  would there be somebody who could review https://reviews.llvm.org/D69585
> > so
> > that it can make it into 10.0? I can get significant build time reduction
> > with the patch when using PCHs (up to 20-30% build time,
> >
> > http://llunak.blogspot.com/2019/11/clang-precompiled-headers-and-improvin
> >g.html),
> >
> > the patch is fairly simple, I've been using it locally for several months
> > by
> > now, and it should be pretty safe given that the change is in effect only
> > if
> > opted in.
> >
> >  Thank you.
> >
> > --
> >  Lubos Lunak
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev



-- 
 Lubos Lunak