Yeah... I recall observing this when I was doing other bool related optimization work, but I never got around to fixing it.
Reviewed-by: Ian Romanick <ian.d.roman...@intel.com> On 10/15/2014 08:51 PM, Kenneth Graunke wrote: > Previously, we generated an extra CMP instruction: > > cmp.ge.f0(8) g4<1>D g2<0,1,0>F 0F > cmp.nz.f0(8) null g4<8,8,1>D 0D > (+f0) sel(8) g120<1>F g2.4<0,1,0>F g3<0,1,0>F > > The first operand is always a boolean, and we want to predicate the SEL > on that. Rather than producing a boolean value and comparing it against > zero, we can just produce a condition code in the flag register. > > Now we generate: > > cmp.ge.f0(8) null g2<0,1,0>F 0F > (+f0) sel(8) g124<1>F g2.4<0,1,0>F g3<0,1,0>F > > total instructions in shared programs: 5473459 -> 5473253 (-0.00%) > instructions in affected programs: 6219 -> 6013 (-3.31%) > > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > --- > src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp > b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp > index 8a11b04..3ba5492 100644 > --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp > +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp > @@ -487,6 +487,19 @@ fs_visitor::visit(ir_expression *ir) > return; > break; > > + case ir_triop_csel: > + ir->operands[1]->accept(this); > + op[1] = this->result; > + ir->operands[2]->accept(this); > + op[2] = this->result; > + > + emit_bool_to_cond_code(ir->operands[0]); > + > + this->result = fs_reg(this, ir->type); > + inst = emit(SEL(this->result, op[1], op[2])); > + inst->predicate = BRW_PREDICATE_NORMAL; > + return; > + > case ir_unop_interpolate_at_centroid: > case ir_binop_interpolate_at_offset: > case ir_binop_interpolate_at_sample: > @@ -1023,11 +1036,6 @@ fs_visitor::visit(ir_expression *ir) > break; > > case ir_triop_csel: > - emit(CMP(reg_null_d, op[0], fs_reg(0), BRW_CONDITIONAL_NZ)); > - inst = emit(BRW_OPCODE_SEL, this->result, op[1], op[2]); > - inst->predicate = BRW_PREDICATE_NORMAL; > - break; > - > case ir_unop_interpolate_at_centroid: > case ir_binop_interpolate_at_offset: > case ir_binop_interpolate_at_sample: > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
