On Wed, Jul 14, 2010 at 09:16:15PM -0700, Segovia, Benjamin wrote: > Thanks for that. It may be clearly useful. > > FYW, I output big shaders from nexuiz (> 100 inst) and clearly swizzling > kills opportunities of optimizations. A serie of instructions may be totally > useless but swizzles make the flow analysis more complicated. > For big nexuiz fragment shaders, almost all the moves may be removed. This > may lead to remove almost 40% of the instructions in these cases. > > I am not sure of the final speed up at the end. Intel GPUs use SoA > computations for the fragment programs. So, it should be easy to completely > remove the swizzle and to consider everything scalar. In that case, flow > analysis becomes easier. > However, despite that, the Intel Gen output still includes uncessary moves in > particular from GPR to message registers. Not sure it is still related. > > Hmmm. Cool. We may be able anyway to make it faster :) > > Ben >
Hi, As Alex suggested, take a look at the r300 compiler. If you are looking to eliminate MOV instructions, the peephole() function in src/mesa/drivers/dri/r300/compiler/radeon_optimize.c might interest you. It does copy propagation and is a good example of dataflow analysis with swizzles. -Tom _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
