On Mon, Sep 22, 2014 at 9:38 PM, Alex Rosenberg <alexr at leftfield.org> wrote:> Is your answer the same if we're talking about an asm version of zlib > that's faster than the compiled version? Because that's a thing.If zlib is our bottleneck... wow we have bigger issues. And as we work on a compiler, I kinda hope we can produce a reasonable blob of asm in most cases. If not, we should probably get on that. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140923/d65f83b3/attachment.html>
> On Sep 23, 2014, at 1:29 AM, Chandler Carruth <chandlerc at google.com> wrote: > > > On Mon, Sep 22, 2014 at 9:38 PM, Alex Rosenberg <alexr at leftfield.org <mailto:alexr at leftfield.org>> wrote: > Is your answer the same if we're talking about an asm version of zlib that's faster than the compiled version? Because that's a thing. > > If zlib is our bottleneck... wow we have bigger issues. > > And as we work on a compiler, I kinda hope we can produce a reasonable blob of asm in most cases. If not, we should probably get on that.Dang it. Beaten to the punch. I was just going to ask for a bug report that we apparently generate suboptimal code for that. :) Taking my trolling hat back off, I actually am interested in whether it’s reasonable for the compiler to do significantly better here (and on other similar kinds of code). Alex, can you elaborate a bit? -Jim -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140923/e6bb2ff8/attachment.html>
On Sep 23, 2014, at 7:42 AM, Jim Grosbach <grosbach at apple.com> wrote:> > >> On Sep 23, 2014, at 1:29 AM, Chandler Carruth <chandlerc at google.com> wrote: >> >> >>> On Mon, Sep 22, 2014 at 9:38 PM, Alex Rosenberg <alexr at leftfield.org> wrote: >>> Is your answer the same if we're talking about an asm version of zlib that's faster than the compiled version? Because that's a thing. >> >> If zlib is our bottleneck... wow we have bigger issues. >> >> And as we work on a compiler, I kinda hope we can produce a reasonable blob of asm in most cases. If not, we should probably get on that. > > Dang it. Beaten to the punch. I was just going to ask for a bug report that we apparently generate suboptimal code for that. :) > > Taking my trolling hat back off, I actually am interested in whether it’s reasonable for the compiler to do significantly better here (and on other similar kinds of code). Alex, can you elaborate a bit?Zlib has been written in asm a few times over, just check the distribution. I haven't looked too closely at the code, but from my recollection of someone in my team writing a SPU version, it's pretty much a set of transforms that if a compiler could do them would be considered "heroic optimizations" and likely not the sort of thing we'd put in LLVM. Alex -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20140923/8b4f348b/attachment.html>