On 02/10/2015 01:11 PM, Jason Ekstrand wrote: > Looks fine to me but why are we still adding algebraic optimizations to > GLSL-IR?
Some cases, though this is not one, can slightly reduce memory usage. GLSL IR will likely live on for some time as the pre-linked IR, so that's a benefit we shouldn't discount. While we are close to enabling NIR on the i965 scalar backend, that leaves a lot of cases (including GS on all platforms, and VS on pre-GEN8 platforms) still needing love... not to mention non-Intel drivers. > Reviewed-by: Jason Ekstrand <jason.ekstr...@intel.com > <mailto:jason.ekstr...@intel.com>> Also Reviewed-by: Ian Romanick <ian.d.roman...@intel.com> > On Feb 10, 2015 12:36 PM, "Matt Turner" <matts...@gmail.com > <mailto:matts...@gmail.com>> wrote: > > Lots of shaders divide by exp2(...) which we turn into a multiplication > by the reciprocal. We can avoid the reciprocal by simply negating exp2's > argument. > > total instructions in shared programs: 5947154 -> 5946695 (-0.01%) > instructions in affected programs: 118661 -> 118202 (-0.39%) > helped: 380 > --- > src/glsl/opt_algebraic.cpp | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/src/glsl/opt_algebraic.cpp b/src/glsl/opt_algebraic.cpp > index c6f4a9c..616ed37 100644 > --- a/src/glsl/opt_algebraic.cpp > +++ b/src/glsl/opt_algebraic.cpp > @@ -747,6 +747,12 @@ > ir_algebraic_visitor::handle_expression(ir_expression *ir) > if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp) > return op_expr[0]->operands[0]; > > + if (op_expr[0] && (op_expr[0]->operation == ir_unop_exp2 || > + op_expr[0]->operation == ir_unop_exp)) { > + return new(mem_ctx) ir_expression(op_expr[0]->operation, > ir->type, > + > neg(op_expr[0]->operands[0])); > + } > + > /* While ir_to_mesa.cpp will lower sqrt(x) to rcp(rsq(x)), it > does so at > * its IR level, so we can always apply this transformation. > */ > -- > 2.0.5 > > _______________________________________________ > 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
