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/*
* Copyright © 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
*
*/
#include "main/macros.h"
#include "program/program.h"
#include "program/prog_print.h"
#include "brw_context.h"
#include "brw_defines.h"
#include "brw_eu.h"
static bool
is_single_channel_dp4(struct brw_instruction *insn)
{
if (insn->header.opcode != BRW_OPCODE_DP4 ||
insn->header.execution_size != BRW_EXECUTE_8 ||
insn->header.access_mode != BRW_ALIGN_16 ||
insn->bits1.da1.dest_reg_file != BRW_GENERAL_REGISTER_FILE)
return false;
if (!is_power_of_two(insn->bits1.da16.dest_writemask))
return false;
return true;
}
/**
* Sets the dependency control fields on DP4 instructions.
*
* The hardware only tracks dependencies on a register basis, so when
* you do:
*
* DP4 dst.x src1 src2
* DP4 dst.y src1 src3
* DP4 dst.z src1 src4
* DP4 dst.w src1 src5
*
* It will wait to do the DP4 dst.y until the dst.x is resolved, etc.
* We can examine our instruction stream and set the dependency
* control fields to tell the hardware when to do it.
*
* We may want to extend this to other instructions that are used to
* fill in a channel at a time of the destination register.
*/
static void
brw_set_dp4_dependency_control(struct brw_compile *p)
{
int i;
for (i = 1; i < p->nr_insn; i++) {
struct brw_instruction *insn = &p->store[i];
struct brw_instruction *prev = &p->store[i - 1];
if (!is_single_channel_dp4(prev))
continue;
if (!is_single_channel_dp4(insn)) {
i++;
continue;
}
/* Only avoid hw dep control if the write masks are different
* channels of one reg.
*/
if (insn->bits1.da16.dest_writemask == prev->bits1.da16.dest_writemask)
continue;
if (insn->bits1.da16.dest_reg_nr != prev->bits1.da16.dest_reg_nr)
continue;
/* Check if the second instruction depends on the previous one
* for a src.
*/
if (insn->bits1.da1.src0_reg_file == BRW_GENERAL_REGISTER_FILE &&
(insn->bits2.da1.src0_address_mode != BRW_ADDRESS_DIRECT ||
insn->bits2.da1.src0_reg_nr == insn->bits1.da16.dest_reg_nr))
continue;
if (insn->bits1.da1.src1_reg_file == BRW_GENERAL_REGISTER_FILE &&
(insn->bits3.da1.src1_address_mode != BRW_ADDRESS_DIRECT ||
insn->bits3.da1.src1_reg_nr == insn->bits1.da16.dest_reg_nr))
continue;
prev->header.dependency_control |= BRW_DEPENDENCY_NOTCLEARED;
insn->header.dependency_control |= BRW_DEPENDENCY_NOTCHECKED;
}
}
void
brw_optimize(struct brw_compile *p)
{
brw_set_dp4_dependency_control(p);
}
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