On Tue, Mar 17, 2015 at 11:38 AM, Matt Turner <matts...@gmail.com> wrote: > On Mon, Mar 16, 2015 at 9:21 PM, Jason Ekstrand <ja...@jlekstrand.net> wrote: >> Because of the way that NIR does conditionals, we get them in any old SSA >> value. The actual boolean value used in the select or if is x != 0. >> Previously, we handled this by emitting a mov.nz to move the value to the >> flag register. However, this almost always adds at least one if not two >> instructions because we have to go through the VGRF when we could be >> comparing directly to the flag and then using the flag. >> >> With this commit, we simply re-emit the instruction that produces the value >> when we can. By doing so, we can use the flag directly and we trust in CSE >> to clean up for us if it can. >> >> Shader-db results: >> >> total instructions in shared programs: 4164120 -> 4110511 (-1.29%) >> instructions in affected programs: 2397042 -> 2343433 (-2.24%) >> helped: 13167 >> HURT: 31 >> GAINED: 4 >> LOST: 4 >> --- > > A small change to the cmod_propagation branch accomplishes most of this -- > > total instructions in shared programs: 7850607 -> 7793875 (-0.72%) > instructions in affected programs: 2425140 -> 2368408 (-2.34%) > helped: 13502 > HURT: 0 > GAINED: 1 > LOST: 5 > > We always emit the MOV.NZ with a D-typed destination, which > cmod_propagate won't combine with a CMP with an F-typed destination. > > I don't think we ever emit MOV.NZ without NIR, so no changes without it. > > Let me play with this some more.
Another aspect here is how this is going to interact with boolean resolves. I've got patches in my wip/nir-booleans branch that I'm testing right now. I think the general approach is solid, I just need to test and work out the bugs. It could take some time as I am testing on ILK after all. --Jason _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
