src/gallium/drivers/freedreno/ir3/ir3_cp.c - platform/external/mesa3d - Gitiles

 /* -*- mode: C; c-file-style: "k&r"; tab-width 4; indent-tabs-mode: t; -*- */

 /*
  * Copyright (C) 2014 Rob Clark <robclark@freedesktop.org>
  *
  * 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:
  *    Rob Clark <robclark@freedesktop.org>
  */

 #include "freedreno_util.h"

 #include "ir3.h"

 /*
  * Copy Propagate:
  *
  */

 static void block_cp(struct ir3_block *block);
 static struct ir3_instruction * instr_cp(struct ir3_instruction *instr, bool keep);

 /* XXX move this somewhere useful (and rename?) */
 static struct ir3_instruction *ssa(struct ir3_register *reg)
 {
 	if (reg->flags & IR3_REG_SSA)
 		return reg->instr;
 	return NULL;
 }

 static bool conflicts(struct ir3_instruction *a, struct ir3_instruction *b)
 {
 	return (a && b) && (a != b);
 }

 static void set_neighbors(struct ir3_instruction *instr,
 		struct ir3_instruction *left, struct ir3_instruction *right)
 {
 	debug_assert(!conflicts(instr->cp.left, left));
 	if (left) {
 		instr->cp.left_cnt++;
 		instr->cp.left = left;
 	}
 	debug_assert(!conflicts(instr->cp.right, right));
 	if (right) {
 		instr->cp.right_cnt++;
 		instr->cp.right = right;
 	}
 }

 /* remove neighbor reference, clearing left/right neighbor ptrs when
  * there are no more references:
  */
 static void remove_neighbors(struct ir3_instruction *instr)
 {
 	if (instr->cp.left) {
 		if (--instr->cp.left_cnt == 0)
 			instr->cp.left = NULL;
 	}
 	if (instr->cp.right) {
 		if (--instr->cp.right_cnt == 0)
 			instr->cp.right = NULL;
 	}
 }

 /* stop condition for iteration: */
 static bool check_stop(struct ir3_instruction *instr)
 {
 	if (ir3_instr_check_mark(instr))
 		return true;

 	/* stay within the block.. don't try to operate across
 	 * basic block boundaries or we'll have problems when
 	 * dealing with multiple basic blocks:
 	 */
 	if (is_meta(instr) && (instr->opc == OPC_META_INPUT))
 		return true;

 	return false;
 }

 static bool is_eligible_mov(struct ir3_instruction *instr)
 {
 	if ((instr->category == 1) &&
 			(instr->cat1.src_type == instr->cat1.dst_type)) {
 		struct ir3_register *dst = instr->regs[0];
 		struct ir3_register *src = instr->regs[1];
 		struct ir3_instruction *src_instr = ssa(src);
 		if (dst->flags & IR3_REG_ADDR)
 			return false;
 		/* TODO: propagate abs/neg modifiers if possible */
 		if (src->flags & (IR3_REG_ABS | IR3_REG_NEGATE | IR3_REG_RELATIV))
 			return false;
 		if (src_instr) {
 			/* check that eliminating the move won't result in
 			 * a neighbor conflict, ie. if an instruction feeds
 			 * into multiple fanins it can still only have at
 			 * most one left and one right neighbor:
 			 */
 			if (conflicts(instr->cp.left, src_instr->cp.left))
 				return false;
 			if (conflicts(instr->cp.right, src_instr->cp.right))
 				return false;
 			return true;
 		}
 	}
 	return false;
 }

 static void walk_children(struct ir3_instruction *instr, bool keep)
 {
 	unsigned i;

 	/* walk down the graph from each src: */
 	for (i = 1; i < instr->regs_count; i++) {
 		struct ir3_register *src = instr->regs[i];
 		if (src->flags & IR3_REG_SSA)
 			src->instr = instr_cp(src->instr, keep);
 	}
 }

 static struct ir3_instruction *
 instr_cp_fanin(struct ir3_instruction *instr)
 {
 	unsigned i, j;

 	/* we need to handle fanin specially, to detect cases
 	 * when we need to keep a mov
 	 */

 	for (i = 1; i < instr->regs_count; i++) {
 		struct ir3_register *src = instr->regs[i];
 		if (src->flags & IR3_REG_SSA) {
 			struct ir3_instruction *cand =
 					instr_cp(src->instr, false);

 			/* if the candidate is a fanout, then keep
 			 * the move.
 			 *
 			 * This is a bit, um, fragile, but it should
 			 * catch the extra mov's that the front-end
 			 * puts in for us already in these cases.
 			 */
 			if (is_meta(cand) && (cand->opc == OPC_META_FO))
 				cand = instr_cp(src->instr, true);

 			/* we can't have 2 registers referring to the same instruction, so
 			 * go through and check if any already refer to the candidate
 			 * instruction. if so, don't do the propagation.
 			 *
 			 * NOTE: we need to keep this, despite the neighbor
 			 * conflict checks, to avoid A<->B<->A..
 			 */
 			for (j = 1; j < instr->regs_count; j++)
 				if (instr->regs[j]->instr == cand)
 					break;
 			if (j == instr->regs_count)
 				src->instr = cand;
 		}
 	}

 	walk_children(instr, false);

 	return instr;
 }

 static struct ir3_instruction *
 instr_cp(struct ir3_instruction *instr, bool keep)
 {
 	/* if we've already visited this instruction, bail now: */
 	if (check_stop(instr))
 		return instr;

 	if (is_meta(instr) && (instr->opc == OPC_META_FI))
 		return instr_cp_fanin(instr);

 	if (!keep && is_eligible_mov(instr)) {
 		struct ir3_instruction *src_instr = ssa(instr->regs[1]);
 		set_neighbors(src_instr, instr->cp.left, instr->cp.right);
 		remove_neighbors(instr);
 		return instr_cp(src_instr, false);
 	}

 	walk_children(instr, false);

 	return instr;
 }

 static void block_cp(struct ir3_block *block)
 {
 	unsigned i, j;

 	for (i = 0; i < block->noutputs; i++) {
 		if (block->outputs[i]) {
 			struct ir3_instruction *out =
 					instr_cp(block->outputs[i], false);

 			/* To deal with things like this:
 			 *
 			 *   43: MOV OUT[2], TEMP[5]
 			 *   44: MOV OUT[0], TEMP[5]
 			 *
 			 * we need to ensure that no two outputs point to
 			 * the same instruction
 			 */
 			for (j = 0; j < i; j++) {
 				if (block->outputs[j] == out) {
 					out = instr_cp(block->outputs[i], true);
 					break;
 				}
 			}

 			block->outputs[i] = out;
 		}
 	}
 }

 /*
  * Find instruction neighbors:
  */

 static void instr_find_neighbors(struct ir3_instruction *instr)
 {
 	unsigned i;

 	if (check_stop(instr))
 		return;

 	if (is_meta(instr) && (instr->opc == OPC_META_FI)) {
 		unsigned n = instr->regs_count;
 		for (i = 1; i < n; i++) {
 			struct ir3_instruction *src_instr = ssa(instr->regs[i]);
 			if (src_instr) {
 				struct ir3_instruction *left = (i > 1) ?
 						ssa(instr->regs[i-1]) : NULL;
 				struct ir3_instruction *right = (i < (n - 1)) ?
 						ssa(instr->regs[i+1]) : NULL;
 				set_neighbors(src_instr, left, right);
 				instr_find_neighbors(src_instr);
 			}
 		}
 	} else {
 		for (i = 1; i < instr->regs_count; i++) {
 			struct ir3_instruction *src_instr = ssa(instr->regs[i]);
 			if (src_instr)
 				instr_find_neighbors(src_instr);
 		}
 	}
 }

 static void block_find_neighbors(struct ir3_block *block)
 {
 	unsigned i;

 	for (i = 0; i < block->noutputs; i++) {
 		if (block->outputs[i]) {
 			struct ir3_instruction *instr = block->outputs[i];
 			instr_find_neighbors(instr);
 		}
 	}
 }

 static void instr_clear_neighbors(struct ir3_instruction *instr)
 {
 	unsigned i;

 	if (check_stop(instr))
 		return;

 	instr->cp.left_cnt = 0;
 	instr->cp.left = NULL;
 	instr->cp.right_cnt = 0;
 	instr->cp.right = NULL;

 	for (i = 1; i < instr->regs_count; i++) {
 		struct ir3_instruction *src_instr = ssa(instr->regs[i]);
 		if (src_instr)
 			instr_clear_neighbors(src_instr);
 	}
 }

 static void block_clear_neighbors(struct ir3_block *block)
 {
 	unsigned i;

 	for (i = 0; i < block->noutputs; i++) {
 		if (block->outputs[i]) {
 			struct ir3_instruction *instr = block->outputs[i];
 			instr_clear_neighbors(instr);
 		}
 	}
 }

 void ir3_block_cp(struct ir3_block *block)
 {
 	ir3_clear_mark(block->shader);
 	block_clear_neighbors(block);
 	ir3_clear_mark(block->shader);
 	block_find_neighbors(block);
 	ir3_clear_mark(block->shader);
 	block_cp(block);
 }
	/* -- mode: C; c-file-style: "k&r"; tab-width 4; indent-tabs-mode: t; -- */

	/*
	* Copyright (C) 2014 Rob Clark <robclark@freedesktop.org>
	*
	* 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:
	* Rob Clark <robclark@freedesktop.org>
	*/

	#include "freedreno_util.h"

	#include "ir3.h"

	/*
	* Copy Propagate:
	*
	*/

	static void block_cp(struct ir3_block *block);
	static struct ir3_instruction * instr_cp(struct ir3_instruction *instr, bool keep);

	/* XXX move this somewhere useful (and rename?) */
	static struct ir3_instruction ssa(struct ir3_register reg)
	{
	if (reg->flags & IR3_REG_SSA)
	return reg->instr;
	return NULL;
	}

	static bool conflicts(struct ir3_instruction a, struct ir3_instruction b)
	{
	return (a && b) && (a != b);
	}

	static void set_neighbors(struct ir3_instruction *instr,
	struct ir3_instruction left, struct ir3_instruction right)
	{
	debug_assert(!conflicts(instr->cp.left, left));
	if (left) {
	instr->cp.left_cnt++;
	instr->cp.left = left;
	}
	debug_assert(!conflicts(instr->cp.right, right));
	if (right) {
	instr->cp.right_cnt++;
	instr->cp.right = right;
	}
	}

	/* remove neighbor reference, clearing left/right neighbor ptrs when
	* there are no more references:
	*/
	static void remove_neighbors(struct ir3_instruction *instr)
	{
	if (instr->cp.left) {
	if (--instr->cp.left_cnt == 0)
	instr->cp.left = NULL;
	}
	if (instr->cp.right) {
	if (--instr->cp.right_cnt == 0)
	instr->cp.right = NULL;
	}
	}

	/* stop condition for iteration: */
	static bool check_stop(struct ir3_instruction *instr)
	{
	if (ir3_instr_check_mark(instr))
	return true;

	/* stay within the block.. don't try to operate across
	* basic block boundaries or we'll have problems when
	* dealing with multiple basic blocks:
	*/
	if (is_meta(instr) && (instr->opc == OPC_META_INPUT))
	return true;

	return false;
	}

	static bool is_eligible_mov(struct ir3_instruction *instr)
	{
	if ((instr->category == 1) &&
	(instr->cat1.src_type == instr->cat1.dst_type)) {
	struct ir3_register *dst = instr->regs[0];
	struct ir3_register *src = instr->regs[1];
	struct ir3_instruction *src_instr = ssa(src);
	if (dst->flags & IR3_REG_ADDR)
	return false;
	/* TODO: propagate abs/neg modifiers if possible */
	if (src->flags & (IR3_REG_ABS \| IR3_REG_NEGATE \| IR3_REG_RELATIV))
	return false;
	if (src_instr) {
	/* check that eliminating the move won't result in
	* a neighbor conflict, ie. if an instruction feeds
	* into multiple fanins it can still only have at
	* most one left and one right neighbor:
	*/
	if (conflicts(instr->cp.left, src_instr->cp.left))
	return false;
	if (conflicts(instr->cp.right, src_instr->cp.right))
	return false;
	return true;
	}
	}
	return false;
	}

	static void walk_children(struct ir3_instruction *instr, bool keep)
	{
	unsigned i;

	/* walk down the graph from each src: */
	for (i = 1; i < instr->regs_count; i++) {
	struct ir3_register *src = instr->regs[i];
	if (src->flags & IR3_REG_SSA)
	src->instr = instr_cp(src->instr, keep);
	}
	}

	static struct ir3_instruction *
	instr_cp_fanin(struct ir3_instruction *instr)
	{
	unsigned i, j;

	/* we need to handle fanin specially, to detect cases
	* when we need to keep a mov
	*/

	for (i = 1; i < instr->regs_count; i++) {
	struct ir3_register *src = instr->regs[i];
	if (src->flags & IR3_REG_SSA) {
	struct ir3_instruction *cand =
	instr_cp(src->instr, false);

	/* if the candidate is a fanout, then keep
	* the move.
	*
	* This is a bit, um, fragile, but it should
	* catch the extra mov's that the front-end
	* puts in for us already in these cases.
	*/
	if (is_meta(cand) && (cand->opc == OPC_META_FO))
	cand = instr_cp(src->instr, true);

	/* we can't have 2 registers referring to the same instruction, so
	* go through and check if any already refer to the candidate
	* instruction. if so, don't do the propagation.
	*
	* NOTE: we need to keep this, despite the neighbor
	* conflict checks, to avoid A<->B<->A..
	*/
	for (j = 1; j < instr->regs_count; j++)
	if (instr->regs[j]->instr == cand)
	break;
	if (j == instr->regs_count)
	src->instr = cand;
	}
	}

	walk_children(instr, false);

	return instr;
	}

	static struct ir3_instruction *
	instr_cp(struct ir3_instruction *instr, bool keep)
	{
	/* if we've already visited this instruction, bail now: */
	if (check_stop(instr))
	return instr;

	if (is_meta(instr) && (instr->opc == OPC_META_FI))
	return instr_cp_fanin(instr);

	if (!keep && is_eligible_mov(instr)) {
	struct ir3_instruction *src_instr = ssa(instr->regs[1]);
	set_neighbors(src_instr, instr->cp.left, instr->cp.right);
	remove_neighbors(instr);
	return instr_cp(src_instr, false);
	}

	walk_children(instr, false);

	return instr;
	}

	static void block_cp(struct ir3_block *block)
	{
	unsigned i, j;

	for (i = 0; i < block->noutputs; i++) {
	if (block->outputs[i]) {
	struct ir3_instruction *out =
	instr_cp(block->outputs[i], false);

	/* To deal with things like this:
	*
	* 43: MOV OUT[2], TEMP[5]
	* 44: MOV OUT[0], TEMP[5]
	*
	* we need to ensure that no two outputs point to
	* the same instruction
	*/
	for (j = 0; j < i; j++) {
	if (block->outputs[j] == out) {
	out = instr_cp(block->outputs[i], true);
	break;
	}
	}

	block->outputs[i] = out;
	}
	}
	}

	/*
	* Find instruction neighbors:
	*/

	static void instr_find_neighbors(struct ir3_instruction *instr)
	{
	unsigned i;

	if (check_stop(instr))
	return;

	if (is_meta(instr) && (instr->opc == OPC_META_FI)) {
	unsigned n = instr->regs_count;
	for (i = 1; i < n; i++) {
	struct ir3_instruction *src_instr = ssa(instr->regs[i]);
	if (src_instr) {
	struct ir3_instruction *left = (i > 1) ?
	ssa(instr->regs[i-1]) : NULL;
	struct ir3_instruction *right = (i < (n - 1)) ?
	ssa(instr->regs[i+1]) : NULL;
	set_neighbors(src_instr, left, right);
	instr_find_neighbors(src_instr);
	}
	}
	} else {
	for (i = 1; i < instr->regs_count; i++) {
	struct ir3_instruction *src_instr = ssa(instr->regs[i]);
	if (src_instr)
	instr_find_neighbors(src_instr);
	}
	}
	}

	static void block_find_neighbors(struct ir3_block *block)
	{
	unsigned i;

	for (i = 0; i < block->noutputs; i++) {
	if (block->outputs[i]) {
	struct ir3_instruction *instr = block->outputs[i];
	instr_find_neighbors(instr);
	}
	}
	}

	static void instr_clear_neighbors(struct ir3_instruction *instr)
	{
	unsigned i;

	if (check_stop(instr))
	return;

	instr->cp.left_cnt = 0;
	instr->cp.left = NULL;
	instr->cp.right_cnt = 0;
	instr->cp.right = NULL;

	for (i = 1; i < instr->regs_count; i++) {
	struct ir3_instruction *src_instr = ssa(instr->regs[i]);
	if (src_instr)
	instr_clear_neighbors(src_instr);
	}
	}

	static void block_clear_neighbors(struct ir3_block *block)
	{
	unsigned i;

	for (i = 0; i < block->noutputs; i++) {
	if (block->outputs[i]) {
	struct ir3_instruction *instr = block->outputs[i];
	instr_clear_neighbors(instr);
	}
	}
	}

	void ir3_block_cp(struct ir3_block *block)
	{
	ir3_clear_mark(block->shader);
	block_clear_neighbors(block);
	ir3_clear_mark(block->shader);
	block_find_neighbors(block);
	ir3_clear_mark(block->shader);
	block_cp(block);
	}