On 17 December 2013 11:07, Patrick Baggett <baggett.patr...@gmail.com>wrote:
> > > > On Tue, Dec 17, 2013 at 10:59 AM, Paul Berry <stereotype...@gmail.com>wrote: > >> On 17 December 2013 08:46, Tom Stellard <t...@stellard.net> wrote: >> >>> On Tue, Dec 17, 2013 at 09:57:31AM -0600, Patrick Baggett wrote: >>> > Hi all, >>> > >>> > Is there a way to see the machine code that is generated by the GLSL >>> > compiler for all GPU instruction sets? For example, I would like to >>> know if >>> > the optimizer optimizes certain (equivalent) constructs (or not), and >>> avoid >>> > them if possible. I know there is a lot to optimization on GPUs that I >>> > don't know, but I'd still like to get some ballpark estimates. For >>> example, >>> > I'm curious whether: >>> >>> Each driver has its own environment variable for dumping machine code. >>> >>> llvmpipe: GALLIVM_DEBUG=asm (I think you need to build mesa >>> with --enable-debug for this to work) >>> r300g: RADEON_DEBUG=fp,vp >>> r600g, radeonsi: R600_DEBUG=ps,vs >>> >>> I'm not sure what the other drivers use. >>> >>> -Tom >>> >> >> I believe every driver also supports MESA_GLSL=dump, which prints out the >> IR both before and after linking (you'll want to look at the version after >> linking to see what optimizations have been applied, since some >> optimizations happen at link time). Looking at the IR rather than the >> machine code is more likely to give you the information you need, since >> Mesa performs the same IR-level optimizations on all architectures, whereas >> the optimizations that happen at machine code level are vastly different >> from one driver to the next. >> >> > I do want to see both, actually. For example, if a driver implements a > specific optimization (machine code level) and another driver clearly does > not, then that would be considered "interesting" to me. > Ok, in that case the environment variable you want for seeing the generated assembly code for Intel is: INTEL_DEBUG=vs,fs,gs > > > >> Another thing which might be useful to you is Aras Pranckevičius's >> "glsl-optimizer" project (https://github.com/aras-p/glsl-optimizer), >> which performs Mesa's IR-level optimizations on a shader and then >> translates it from IR back to GLSL. >> >> Paul >> >> > Thanks to everyone for the great tips! > > >> >>> > >>> > //let p1, p2, p3 be vec2 uniforms >>> > >>> > vec4(p1, 0, 0) + vec4(p2, 0, 0) + vec4(p3, 0, 1) >>> > >>> > produces identical machine code as: >>> > >>> > vec4(p1+p2+p3, 0, 1); >>> > >>> > for all architectures supported by Mesa. >>> >>> > _______________________________________________ >>> > mesa-dev mailing list >>> > mesa-dev@lists.freedesktop.org >>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev >>> >>> _______________________________________________ >>> mesa-dev mailing list >>> mesa-dev@lists.freedesktop.org >>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev >>> >> >> >
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