/*
* 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.
*/
/**
* \file opt_algebraic.cpp
*
* Takes advantage of association, commutivity, and other algebraic
* properties to simplify expressions.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "ir_rvalue_visitor.h"
#include "ir_optimization.h"
#include "glsl_types.h"
/**
* Visitor class for replacing expressions with ir_constant values.
*/
class ir_algebraic_visitor : public ir_rvalue_visitor {
public:
ir_algebraic_visitor()
{
this->progress = false;
this->mem_ctx = NULL;
}
virtual ~ir_algebraic_visitor()
{
}
ir_rvalue *handle_expression(ir_expression *ir);
void handle_rvalue(ir_rvalue **rvalue);
bool reassociate_constant(ir_expression *ir1,
int const_index,
ir_constant *constant,
ir_expression *ir2);
void reassociate_operands(ir_expression *ir1,
int op1,
ir_expression *ir2,
int op2);
ir_rvalue *swizzle_if_required(ir_expression *expr,
ir_rvalue *operand);
void *mem_ctx;
bool progress;
};
static inline bool
is_vec_zero(ir_constant *ir)
{
return (ir == NULL) ? false : ir->is_zero();
}
static inline bool
is_vec_one(ir_constant *ir)
{
return (ir == NULL) ? false : ir->is_one();
}
static void
update_type(ir_expression *ir)
{
if (ir->operands[0]->type->is_vector())
ir->type = ir->operands[0]->type;
else
ir->type = ir->operands[1]->type;
}
void
ir_algebraic_visitor::reassociate_operands(ir_expression *ir1,
int op1,
ir_expression *ir2,
int op2)
{
ir_rvalue *temp = ir2->operands[op2];
ir2->operands[op2] = ir1->operands[op1];
ir1->operands[op1] = temp;
/* Update the type of ir2. The type of ir1 won't have changed --
* base types matched, and at least one of the operands of the 2
* binops is still a vector if any of them were.
*/
update_type(ir2);
this->progress = true;
}
/**
* Reassociates a constant down a tree of adds or multiplies.
*
* Consider (2 * (a * (b * 0.5))). We want to send up with a * b.
*/
bool
ir_algebraic_visitor::reassociate_constant(ir_expression *ir1, int const_index,
ir_constant *constant,
ir_expression *ir2)
{
if (!ir2 || ir1->operation != ir2->operation)
return false;
/* Don't want to even think about matrices. */
if (ir1->operands[0]->type->is_matrix() ||
ir1->operands[1]->type->is_matrix() ||
ir2->operands[0]->type->is_matrix() ||
ir2->operands[1]->type->is_matrix())
return false;
ir_constant *ir2_const[2];
ir2_const[0] = ir2->operands[0]->constant_expression_value();
ir2_const[1] = ir2->operands[1]->constant_expression_value();
if (ir2_const[0] && ir2_const[1])
return false;
if (ir2_const[0]) {
reassociate_operands(ir1, const_index, ir2, 1);
return true;
} else if (ir2_const[1]) {
reassociate_operands(ir1, const_index, ir2, 0);
return true;
}
if (reassociate_constant(ir1, const_index, constant,
ir2->operands[0]->as_expression())) {
update_type(ir2);
return true;
}
if (reassociate_constant(ir1, const_index, constant,
ir2->operands[1]->as_expression())) {
update_type(ir2);
return true;
}
return false;
}
/* When eliminating an expression and just returning one of its operands,
* we may need to swizzle that operand out to a vector if the expression was
* vector type.
*/
ir_rvalue *
ir_algebraic_visitor::swizzle_if_required(ir_expression *expr,
ir_rvalue *operand)
{
if (expr->type->is_vector() && operand->type->is_scalar()) {
return new(mem_ctx) ir_swizzle(operand, 0, 0, 0, 0,
expr->type->vector_elements);
} else
return operand;
}
ir_rvalue *
ir_algebraic_visitor::handle_expression(ir_expression *ir)
{
ir_constant *op_const[2] = {NULL, NULL};
ir_expression *op_expr[2] = {NULL, NULL};
ir_expression *temp;
unsigned int i;
assert(ir->get_num_operands() <= 2);
for (i = 0; i < ir->get_num_operands(); i++) {
if (ir->operands[i]->type->is_matrix())
return ir;
op_const[i] = ir->operands[i]->constant_expression_value();
op_expr[i] = ir->operands[i]->as_expression();
}
if (this->mem_ctx == NULL)
this->mem_ctx = ralloc_parent(ir);
switch (ir->operation) {
case ir_unop_logic_not: {
enum ir_expression_operation new_op = ir_unop_logic_not;
if (op_expr[0] == NULL)
break;
switch (op_expr[0]->operation) {
case ir_binop_less: new_op = ir_binop_gequal; break;
case ir_binop_greater: new_op = ir_binop_lequal; break;
case ir_binop_lequal: new_op = ir_binop_greater; break;
case ir_binop_gequal: new_op = ir_binop_less; break;
case ir_binop_equal: new_op = ir_binop_nequal; break;
case ir_binop_nequal: new_op = ir_binop_equal; break;
case ir_binop_all_equal: new_op = ir_binop_any_nequal; break;
case ir_binop_any_nequal: new_op = ir_binop_all_equal; break;
default:
/* The default case handler is here to silence a warning from GCC.
*/
break;
}
if (new_op != ir_unop_logic_not) {
this->progress = true;
return new(mem_ctx) ir_expression(new_op,
ir->type,
op_expr[0]->operands[0],
op_expr[0]->operands[1]);
}
break;
}
case ir_binop_add:
if (is_vec_zero(op_const[0])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[1]);
}
if (is_vec_zero(op_const[1])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[0]);
}
/* Reassociate addition of constants so that we can do constant
* folding.
*/
if (op_const[0] && !op_const[1])
reassociate_constant(ir, 0, op_const[0],
ir->operands[1]->as_expression());
if (op_const[1] && !op_const[0])
reassociate_constant(ir, 1, op_const[1],
ir->operands[0]->as_expression());
break;
case ir_binop_sub:
if (is_vec_zero(op_const[0])) {
this->progress = true;
temp = new(mem_ctx) ir_expression(ir_unop_neg,
ir->operands[1]->type,
ir->operands[1],
NULL);
return swizzle_if_required(ir, temp);
}
if (is_vec_zero(op_const[1])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[0]);
}
break;
case ir_binop_mul:
if (is_vec_one(op_const[0])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[1]);
}
if (is_vec_one(op_const[1])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[0]);
}
if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) {
this->progress = true;
return ir_constant::zero(ir, ir->type);
}
/* Reassociate multiplication of constants so that we can do
* constant folding.
*/
if (op_const[0] && !op_const[1])
reassociate_constant(ir, 0, op_const[0],
ir->operands[1]->as_expression());
if (op_const[1] && !op_const[0])
reassociate_constant(ir, 1, op_const[1],
ir->operands[0]->as_expression());
break;
case ir_binop_div:
if (is_vec_one(op_const[0]) && ir->type->base_type == GLSL_TYPE_FLOAT) {
this->progress = true;
temp = new(mem_ctx) ir_expression(ir_unop_rcp,
ir->operands[1]->type,
ir->operands[1],
NULL);
return swizzle_if_required(ir, temp);
}
if (is_vec_one(op_const[1])) {
this->progress = true;
return swizzle_if_required(ir, ir->operands[0]);
}
break;
case ir_binop_logic_and:
/* FINISHME: Also simplify (a && a) to (a). */
if (is_vec_one(op_const[0])) {
this->progress = true;
return ir->operands[1];
} else if (is_vec_one(op_const[1])) {
this->progress = true;
return ir->operands[0];
} else if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) {
this->progress = true;
return ir_constant::zero(mem_ctx, ir->type);
}
break;
case ir_binop_logic_xor:
/* FINISHME: Also simplify (a ^^ a) to (false). */
if (is_vec_zero(op_const[0])) {
this->progress = true;
return ir->operands[1];
} else if (is_vec_zero(op_const[1])) {
this->progress = true;
return ir->operands[0];
} else if (is_vec_one(op_const[0])) {
this->progress = true;
return new(mem_ctx) ir_expression(ir_unop_logic_not, ir->type,
ir->operands[1], NULL);
} else if (is_vec_one(op_const[1])) {
this->progress = true;
return new(mem_ctx) ir_expression(ir_unop_logic_not, ir->type,
ir->operands[0], NULL);
}
break;
case ir_binop_logic_or:
/* FINISHME: Also simplify (a || a) to (a). */
if (is_vec_zero(op_const[0])) {
this->progress = true;
return ir->operands[1];
} else if (is_vec_zero(op_const[1])) {
this->progress = true;
return ir->operands[0];
} else if (is_vec_one(op_const[0]) || is_vec_one(op_const[1])) {
ir_constant_data data;
for (unsigned i = 0; i < 16; i++)
data.b[i] = true;
this->progress = true;
return new(mem_ctx) ir_constant(ir->type, &data);
}
break;
case ir_unop_rcp:
if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp) {
this->progress = true;
return op_expr[0]->operands[0];
}
/* FINISHME: We should do rcp(rsq(x)) -> sqrt(x) for some
* backends, except that some backends will have done sqrt ->
* rcp(rsq(x)) and we don't want to undo it for them.
*/
/* As far as we know, all backends are OK with rsq. */
if (op_expr[0] && op_expr[0]->operation == ir_unop_sqrt) {
this->progress = true;
temp = new(mem_ctx) ir_expression(ir_unop_rsq,
op_expr[0]->operands[0]->type,
op_expr[0]->operands[0],
NULL);
return swizzle_if_required(ir, temp);
}
break;
default:
break;
}
return ir;
}
void
ir_algebraic_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_expression *expr = (*rvalue)->as_expression();
if (!expr || expr->operation == ir_quadop_vector)
return;
*rvalue = handle_expression(expr);
}
bool
do_algebraic(exec_list *instructions)
{
ir_algebraic_visitor v;
visit_list_elements(&v, instructions);
return v.progress;
}