From: Eric Anholt Date: Tue, 13 Mar 2012 21:19:31 +0000 (-0700) Subject: i965/fs: Avoid generating extra AND instructions on bool logic ops. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=80ecb8f15b9ad7d6edcc85bd19f1867c368b09b6;p=mesa.git i965/fs: Avoid generating extra AND instructions on bool logic ops. By making a bool fs_reg only have a defined low bit (matching CMP output), instead of being a full 0 or 1 value, we reduce the ANDs generated in logic chains like: if (v_texcoord.x < 0.0 || v_texcoord.x > texwidth || v_texcoord.y < 0.0 || v_texcoord.y > 1.0) discard; My concern originally when writing this code was that we would end up generating unnecessary ANDs on bool uniforms, so I put the ANDs right at the point of doing the CMPs that otherwise set only the low bit. However, in order to use a bool, we're generating some instruction anyway (e.g. moving it so as to produce a condition code update), and those instructions can often be turned into an AND at that point. It turns out in the shaders I have on hand, none of them regress in instruction count: Total instructions: 262649 -> 262545 39/2148 programs affected (1.8%) 14253 -> 14149 instructions in affected programs (0.7% reduction) --- diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp index 0cb75f9d5b3..51c1fd24275 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp @@ -397,7 +397,6 @@ fs_visitor::visit(ir_expression *ir) inst = emit(BRW_OPCODE_CMP, temp, op[0], op[1]); inst->conditional_mod = brw_conditional_for_comparison(ir->operation); - emit(BRW_OPCODE_AND, this->result, this->result, fs_reg(0x1)); break; case ir_binop_logic_xor: @@ -443,11 +442,19 @@ fs_visitor::visit(ir_expression *ir) break; case ir_unop_i2f: case ir_unop_u2f: - case ir_unop_b2f: - case ir_unop_b2i: case ir_unop_f2i: emit(BRW_OPCODE_MOV, this->result, op[0]); break; + + case ir_unop_b2i: + inst = emit(BRW_OPCODE_AND, this->result, op[0], fs_reg(1)); + break; + case ir_unop_b2f: + temp = fs_reg(this, glsl_type::int_type); + emit(BRW_OPCODE_AND, temp, op[0], fs_reg(1)); + emit(BRW_OPCODE_MOV, this->result, temp); + break; + case ir_unop_f2b: case ir_unop_i2b: temp = this->result; @@ -459,7 +466,6 @@ fs_visitor::visit(ir_expression *ir) inst = emit(BRW_OPCODE_CMP, temp, op[0], fs_reg(0.0f)); inst->conditional_mod = BRW_CONDITIONAL_NZ; - inst = emit(BRW_OPCODE_AND, this->result, this->result, fs_reg(1)); break; case ir_unop_trunc: @@ -1491,19 +1497,9 @@ fs_visitor::emit_bool_to_cond_code(ir_rvalue *ir) break; case ir_binop_logic_xor: - inst = emit(BRW_OPCODE_XOR, reg_null_d, op[0], op[1]); - inst->conditional_mod = BRW_CONDITIONAL_NZ; - break; - case ir_binop_logic_or: - inst = emit(BRW_OPCODE_OR, reg_null_d, op[0], op[1]); - inst->conditional_mod = BRW_CONDITIONAL_NZ; - break; - case ir_binop_logic_and: - inst = emit(BRW_OPCODE_AND, reg_null_d, op[0], op[1]); - inst->conditional_mod = BRW_CONDITIONAL_NZ; - break; + goto out; case ir_unop_f2b: if (intel->gen >= 6) { @@ -1544,15 +1540,11 @@ fs_visitor::emit_bool_to_cond_code(ir_rvalue *ir) return; } +out: ir->accept(this); - if (intel->gen >= 6) { - fs_inst *inst = emit(BRW_OPCODE_AND, reg_null_d, this->result, fs_reg(1)); - inst->conditional_mod = BRW_CONDITIONAL_NZ; - } else { - fs_inst *inst = emit(BRW_OPCODE_MOV, reg_null_d, this->result); - inst->conditional_mod = BRW_CONDITIONAL_NZ; - } + fs_inst *inst = emit(BRW_OPCODE_AND, reg_null_d, this->result, fs_reg(1)); + inst->conditional_mod = BRW_CONDITIONAL_NZ; } /**