From 4d34c4b5823de984fb8f0469b67c6b4be02030b2 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Wed, 15 Oct 2014 18:57:07 -0700 Subject: [PATCH] i965/fs: Generate better code for ir_triop_csel. 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 Reviewed-by: Ian Romanick Reviewed-by: Matt Turner --- 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 541c25a9a07..3fc9e39484a 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: