12. aug. 2016 04.02 skrev "Timothy Arceri" <<a href="mailto:timothy.arceri@collabora.com">timothy.arceri@collabora.com</a>>: > > On Thu, 2016-08-11 at 20:54 +0200, Thomas Helland wrote: > > 2016-08-11 18:19 GMT+02:00 Ian Romanick <<a href="mailto:idr@freedesktop.org">idr@freedesktop.org</a>>: > > > > > > ping > > > > > > On 07/19/2016 10:37 PM, Ian Romanick wrote: > > > > > > > > From: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>> > > > > > > > > Some shaders include code that looks like: > > > > > > > > uniform int i; > > > > uniform vec4 bones[...]; > > > > > > > > foo(bones[i * 3], bones[i * 3 + 1], bones[i * 3 + 2]); > > > > > > > > CSE would do some work on this: > > > > > > > > x = i * 3 > > > > foo(bones[x], bones[x + 1], bones[x + 2]); > > > > > > > > The compiler may then add '<< 4 + base' to the index > > > > calculations. > > > > This results in expressions like > > > > > > > > x = i * 3 > > > > foo(bones[x << 4], bones[(x + 1) << 4], bones[(x + 2) << 4]); > > > > > > > > This may just be me being dense, but why is the compiler adding the > > shift? > > It seems like this would be "un-optimizing" and so it shouldn't be > > added? > > > > This patch is also a good argument for adding a constant > > reassociation pass. > > At least the (a * #b) << #c ---> a * (#b << #c) would be caught > > by that. > > > > I was confused whether the optimization was preserving signed-ness > > correctly > > but after a couple rounds with myself I believe it is correct. > > > > The change looks good and is: > > > > Reviewed-by: Thomas Helland <<a href="mailto:thomashelland90@gmail.com">thomashelland90@gmail.com</a>> > > > > (Oh, and yes, I'm back to hobby mesa development after finally > > securing a new job and a new apartment) > > Congrats and welcome back. > > I did send you an email but just in case you missed it I've picked up > on your loop unrolling work. Thanks! Yeah, I noticed that one. At least I believe I did. I think I might have also replied with some hints and suggestions? At least I meant to. My Gmail doesn't seem perfectly stable; somehow this thread didn't get pushed up in my inbox when it got more replies, so I might have missed something. If so, make sure to ping me! I should probably find out what's up with that mail thing though. > > > > > > > > > > > > > > Just rearranging the math to produce (i * 48) + 16 saves an > > > > instruction, and it allows CSE to do more work. > > > > > > > > x = i * 48; > > > > foo(bones[x], bones[x + 16], bones[x + 32]); > > > > > > > > So, ~6 instructions becomes ~3. > > > > > > > > Some individual shader-db results look pretty bad. However, I > > > > have a > > > > really, really hard time believing the change in estimated cycles > > > > in, > > > > for example, 3dmmes-taiji/51.shader_test after looking that > > > > change in > > > > the generated code. > > > > > > > > G45 > > > > total instructions in shared programs: 4020840 -> 4010070 (- > > > > 0.27%) > > > > instructions in affected programs: 177460 -> 166690 (-6.07%) > > > > helped: 894 > > > > HURT: 0 > > > > > > > > total cycles in shared programs: 98829000 -> 98784990 (-0.04%) > > > > cycles in affected programs: 3936648 -> 3892638 (-1.12%) > > > > helped: 894 > > > > HURT: 0 > > > > > > > > Ironlake > > > > total instructions in shared programs: 6418887 -> 6408117 (- > > > > 0.17%) > > > > instructions in affected programs: 177460 -> 166690 (-6.07%) > > > > helped: 894 > > > > HURT: 0 > > > > > > > > total cycles in shared programs: 143504542 -> 143460532 (-0.03%) > > > > cycles in affected programs: 3936648 -> 3892638 (-1.12%) > > > > helped: 894 > > > > HURT: 0 > > > > > > > > Sandy Bridge > > > > total instructions in shared programs: 8357887 -> 8339251 (- > > > > 0.22%) > > > > instructions in affected programs: 432715 -> 414079 (-4.31%) > > > > helped: 2795 > > > > HURT: 0 > > > > > > > > total cycles in shared programs: 118284184 -> 118207412 (-0.06%) > > > > cycles in affected programs: 6114626 -> 6037854 (-1.26%) > > > > helped: 2478 > > > > HURT: 317 > > > > > > > > Ivy Bridge > > > > total instructions in shared programs: 7669390 -> 7653822 (- > > > > 0.20%) > > > > instructions in affected programs: 388234 -> 372666 (-4.01%) > > > > helped: 2795 > > > > HURT: 0 > > > > > > > > total cycles in shared programs: 68381982 -> 68263684 (-0.17%) > > > > cycles in affected programs: 1972658 -> 1854360 (-6.00%) > > > > helped: 2458 > > > > HURT: 307 > > > > > > > > Haswell > > > > total instructions in shared programs: 7082636 -> 7067068 (- > > > > 0.22%) > > > > instructions in affected programs: 388234 -> 372666 (-4.01%) > > > > helped: 2795 > > > > HURT: 0 > > > > > > > > total cycles in shared programs: 68282020 -> 68164158 (-0.17%) > > > > cycles in affected programs: 1891820 -> 1773958 (-6.23%) > > > > helped: 2459 > > > > HURT: 261 > > > > > > > > Broadwell > > > > total instructions in shared programs: 9002466 -> 8985875 (- > > > > 0.18%) > > > > instructions in affected programs: 658784 -> 642193 (-2.52%) > > > > helped: 2795 > > > > HURT: 5 > > > > > > > > total cycles in shared programs: 78503092 -> 78450404 (-0.07%) > > > > cycles in affected programs: 2873304 -> 2820616 (-1.83%) > > > > helped: 2275 > > > > HURT: 415 > > > > > > > > Skylake > > > > total instructions in shared programs: 9156978 -> 9140387 (- > > > > 0.18%) > > > > instructions in affected programs: 682625 -> 666034 (-2.43%) > > > > helped: 2795 > > > > HURT: 5 > > > > > > > > total cycles in shared programs: 75591392 -> 75550574 (-0.05%) > > > > cycles in affected programs: 3192120 -> 3151302 (-1.28%) > > > > helped: 2271 > > > > HURT: 425 > > > > > > > > Signed-off-by: Ian Romanick <<a href="mailto:ian.d.romanick@intel.com">ian.d.romanick@intel.com</a>> > > > > --- > > > > src/compiler/nir/nir_opt_algebraic.py | 11 +++++++++++ > > > > 1 file changed, 11 insertions(+) > > > > > > > > diff --git a/src/compiler/nir/nir_opt_algebraic.py > > > > b/src/compiler/nir/nir_opt_algebraic.py > > > > index 0f0896b..37cb700 100644 > > > > --- a/src/compiler/nir/nir_opt_algebraic.py > > > > +++ b/src/compiler/nir/nir_opt_algebraic.py > > > > @@ -119,6 +119,17 @@ optimizations = [ > > > > (('~fadd@64', a, ('fmul', c , ('fadd', b, ('fneg', > > > > a)))), ('flrp', a, b, c), '!options->lower_flrp64'), > > > > (('ffma', a, b, c), ('fadd', ('fmul', a, b), c), 'options- > > > > >lower_ffma'), > > > > (('~fadd', ('fmul', a, b), c), ('ffma', a, b, c), 'options- > > > > >fuse_ffma'), > > > > + > > > > + # (a * #b + #c) << #d > > > > + # ((a * #b) << #d) + (#c << #d) > > > > + # (a * (#b << #d)) + (#c << #d) > > > > + (('ishl', ('iadd', ('imul', a, '#b'), '#c'), '#d'), > > > > + ('iadd', ('imul', a, ('ishl', b, d)), ('ishl', c, d))), > > > > + > > > > + # (a * #b) << #c > > > > + # a * (#b << #c) > > > > + (('ishl', ('imul', a, '#b'), '#c'), ('imul', a, ('ishl', b, > > > > c))), > > > > + > > > > # Comparison simplifications > > > > (('~inot', ('flt', a, b)), ('fge', a, b)), > > > > (('~inot', ('fge', a, b)), ('flt', a, b)), > > > > > > > > > > _______________________________________________ > > > mesa-dev mailing list > > ><a href="mailto:mesa-dev@lists.freedesktop.org"> mesa-dev@lists.freedesktop.org</a> > > ><a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev"> https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> > > _______________________________________________ > > mesa-dev mailing list > ><a href="mailto:mesa-dev@lists.freedesktop.org"> mesa-dev@lists.freedesktop.org</a> > ><a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev"> https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a>