/*
* 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 lower_vector.cpp
* IR lowering pass to remove some types of ir_quadop_vector
*
* \author Ian Romanick <ian.d.romanick@intel.com>
*/
#include "ir.h"
#include "ir_rvalue_visitor.h"
class lower_vector_visitor : public ir_rvalue_visitor {
public:
lower_vector_visitor() : progress(false)
{
/* empty */
}
void handle_rvalue(ir_rvalue **rvalue);
/**
* Should SWZ-like expressions be lowered?
*/
bool dont_lower_swz;
bool progress;
};
/**
* Determine if an IR expression tree looks like an extended swizzle
*
* Extended swizzles consist of access of a single vector source (with possible
* per component negation) and the constants -1, 0, or 1.
*/
bool
is_extended_swizzle(ir_expression *ir)
{
/* Track any variables that are accessed by this expression.
*/
ir_variable *var = NULL;
assert(ir->operation == ir_quadop_vector);
for (unsigned i = 0; i < ir->type->vector_elements; i++) {
ir_rvalue *op = ir->operands[i];
while (op != NULL) {
switch (op->ir_type) {
case ir_type_constant: {
const ir_constant *const c = op->as_constant();
if (!c->is_one() && !c->is_zero() && !c->is_negative_one())
return false;
op = NULL;
break;
}
case ir_type_dereference_variable: {
ir_dereference_variable *const d = (ir_dereference_variable *) op;
if ((var != NULL) && (var != d->var))
return false;
var = d->var;
op = NULL;
break;
}
case ir_type_expression: {
ir_expression *const ex = (ir_expression *) op;
if (ex->operation != ir_unop_neg)
return false;
op = ex->operands[0];
break;
}
case ir_type_swizzle:
op = ((ir_swizzle *) op)->val;
break;
default:
return false;
}
}
}
return true;
}
void
lower_vector_visitor::handle_rvalue(ir_rvalue **rvalue)
{
if (!*rvalue)
return;
ir_expression *expr = (*rvalue)->as_expression();
if ((expr == NULL) || (expr->operation != ir_quadop_vector))
return;
if (this->dont_lower_swz && is_extended_swizzle(expr))
return;
/* FINISHME: Is this the right thing to use for the ralloc context?
*/
void *const mem_ctx = expr;
assert(expr->type->vector_elements == expr->get_num_operands());
/* Generate a temporary with the same type as the ir_quadop_operation.
*/
ir_variable *const temp =
new(mem_ctx) ir_variable(expr->type, "vecop_tmp", ir_var_temporary);
this->base_ir->insert_before(temp);
/* Counter of the number of components collected so far.
*/
unsigned assigned;
/* Write-mask in the destination that receives counted by 'assigned'.
*/
unsigned write_mask;
/* Generate upto four assignments to that variable. Try to group component
* assignments together:
*
* - All constant components can be assigned at once.
* - All assigments of components from a single variable with the same
* unary operator can be assigned at once.
*/
ir_constant_data d = { { 0 } };
assigned = 0;
write_mask = 0;
for (unsigned i = 0; i < expr->type->vector_elements; i++) {
const ir_constant *const c = expr->operands[i]->as_constant();
if (c == NULL)
continue;
switch (expr->type->base_type) {
case GLSL_TYPE_UINT: d.u[assigned] = c->value.u[0]; break;
case GLSL_TYPE_INT: d.i[assigned] = c->value.i[0]; break;
case GLSL_TYPE_FLOAT: d.f[assigned] = c->value.f[0]; break;
case GLSL_TYPE_BOOL: d.b[assigned] = c->value.b[0]; break;
default: assert(!"Should not get here."); break;
}
write_mask |= (1U << i);
assigned++;
}
assert((write_mask == 0) == (assigned == 0));
/* If there were constant values, generate an assignment.
*/
if (assigned > 0) {
ir_constant *const c =
new(mem_ctx) ir_constant(glsl_type::get_instance(expr->type->base_type,
assigned, 0),
&d);
ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
ir_assignment *const assign =
new(mem_ctx) ir_assignment(lhs, c, NULL, write_mask);
this->base_ir->insert_before(assign);
}
/* FINISHME: This should try to coalesce assignments.
*/
for (unsigned i = 0; i < expr->type->vector_elements; i++) {
if (expr->operands[i]->ir_type == ir_type_constant)
continue;
ir_dereference *const lhs = new(mem_ctx) ir_dereference_variable(temp);
ir_assignment *const assign =
new(mem_ctx) ir_assignment(lhs, expr->operands[i], NULL, (1U << i));
this->base_ir->insert_before(assign);
assigned++;
}
assert(assigned == expr->type->vector_elements);
*rvalue = new(mem_ctx) ir_dereference_variable(temp);
this->progress = true;
}
bool
lower_quadop_vector(exec_list *instructions, bool dont_lower_swz)
{
lower_vector_visitor v;
v.dont_lower_swz = dont_lower_swz;
visit_list_elements(&v, instructions);
return v.progress;
}