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i965/fs: Use the embedded compare in SEL on gen6+.

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This avoids the extra CMP and the predication on SEL, so in addition
to one less instruction, it makes scheduling less constrained.

Improves glbenchmark Egypt performance 0.6% +/- 0.2% (n=3).  Reduces
FS instruction count across affected shaders in shader-db by 1.3%
without regressing any.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Eric Anholt
2011-05-12 09:03:24 -07:00
parent 089aa313b4
commit c331b3123e
2 changed files with 30 additions and 16 deletions
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src/mesa/drivers/dri/i965/brw_fs.cpp
+8 -4
View File
@@ -1033,12 +1033,16 @@ fs_visitor::propagate_constants()
scan_inst->src[i] = inst->src[0];
progress = true;
} else if (i == 0 && scan_inst->src[1].file != IMM) {
/* Fit this constant in by swapping the operands and
* flipping the predicate
*/
scan_inst->src[0] = scan_inst->src[1];
scan_inst->src[1] = inst->src[0];
scan_inst->predicate_inverse = !scan_inst->predicate_inverse;
/* If this was predicated, flipping operands means
* we also need to flip the predicate.
*/
if (scan_inst->conditional_mod == BRW_CONDITIONAL_NONE) {
scan_inst->predicate_inverse =
!scan_inst->predicate_inverse;
}
progress = true;
}
break;
src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+22 -12
View File
@@ -386,24 +386,34 @@ fs_visitor::visit(ir_expression *ir)
break;
case ir_binop_min:
/* Unalias the destination */
this->result = fs_reg(this, ir->type);
if (intel->gen >= 6) {
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_L;
} else {
/* Unalias the destination */
this->result = fs_reg(this, ir->type);
inst = emit(BRW_OPCODE_CMP, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_L;
inst = emit(BRW_OPCODE_CMP, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_L;
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->predicated = true;
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->predicated = true;
}
break;
case ir_binop_max:
/* Unalias the destination */
this->result = fs_reg(this, ir->type);
if (intel->gen >= 6) {
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_GE;
} else {
/* Unalias the destination */
this->result = fs_reg(this, ir->type);
inst = emit(BRW_OPCODE_CMP, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_G;
inst = emit(BRW_OPCODE_CMP, this->result, op[0], op[1]);
inst->conditional_mod = BRW_CONDITIONAL_G;
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->predicated = true;
inst = emit(BRW_OPCODE_SEL, this->result, op[0], op[1]);
inst->predicated = true;
}
break;
case ir_binop_pow: