/*
* 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_vec_index_to_cond_assign.cpp
*
* Turns indexing into vector types to a series of conditional moves
* of each channel's swizzle into a temporary.
*
* Most GPUs don't have a native way to do this operation, and this
* works around that. For drivers using both this pass and
* ir_vec_index_to_swizzle, there's a risk that this pass will happen
* before sufficient constant folding to find that the array index is
* constant. However, we hope that other optimization passes,
* particularly constant folding of assignment conditions and copy
* propagation, will result in the same code in the end.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "ir_optimization.h"
#include "glsl_types.h"
/**
* Visitor class for replacing expressions with ir_constant values.
*/
class ir_vec_index_to_cond_assign_visitor : public ir_hierarchical_visitor {
public:
ir_vec_index_to_cond_assign_visitor()
{
progress = false;
}
ir_rvalue *convert_vec_index_to_cond_assign(void *mem_ctx,
ir_rvalue *orig_vector,
ir_rvalue *orig_index,
const glsl_type *type);
ir_rvalue *convert_vector_extract_to_cond_assign(ir_rvalue *ir);
virtual ir_visitor_status visit_enter(ir_expression *);
virtual ir_visitor_status visit_enter(ir_swizzle *);
virtual ir_visitor_status visit_leave(ir_assignment *);
virtual ir_visitor_status visit_enter(ir_return *);
virtual ir_visitor_status visit_enter(ir_call *);
virtual ir_visitor_status visit_enter(ir_if *);
bool progress;
};
ir_rvalue *
ir_vec_index_to_cond_assign_visitor::convert_vec_index_to_cond_assign(void *mem_ctx,
ir_rvalue *orig_vector,
ir_rvalue *orig_index,
const glsl_type *type)
{
ir_assignment *assign, *value_assign;
ir_variable *index, *var, *value;
ir_dereference *deref, *deref_value;
unsigned i;
exec_list list;
/* Store the index to a temporary to avoid reusing its tree. */
index = new(base_ir) ir_variable(glsl_type::int_type,
"vec_index_tmp_i",
ir_var_temporary);
list.push_tail(index);
deref = new(base_ir) ir_dereference_variable(index);
assign = new(base_ir) ir_assignment(deref, orig_index, NULL);
list.push_tail(assign);
/* Store the value inside a temp, thus avoiding matrixes duplication */
value = new(base_ir) ir_variable(orig_vector->type, "vec_value_tmp",
ir_var_temporary);
list.push_tail(value);
deref_value = new(base_ir) ir_dereference_variable(value);
value_assign = new(base_ir) ir_assignment(deref_value, orig_vector);
list.push_tail(value_assign);
/* Temporary where we store whichever value we swizzle out. */
var = new(base_ir) ir_variable(type, "vec_index_tmp_v",
ir_var_temporary);
list.push_tail(var);
/* Generate a single comparison condition "mask" for all of the components
* in the vector.
*/
ir_rvalue *const cond_deref =
compare_index_block(&list, index, 0,
orig_vector->type->vector_elements,
mem_ctx);
/* Generate a conditional move of each vector element to the temp. */
for (i = 0; i < orig_vector->type->vector_elements; i++) {
ir_rvalue *condition_swizzle =
new(base_ir) ir_swizzle(cond_deref->clone(mem_ctx, NULL),
i, 0, 0, 0, 1);
/* Just clone the rest of the deref chain when trying to get at the
* underlying variable.
*/
ir_rvalue *swizzle =
new(base_ir) ir_swizzle(deref_value->clone(mem_ctx, NULL),
i, 0, 0, 0, 1);
deref = new(base_ir) ir_dereference_variable(var);
assign = new(base_ir) ir_assignment(deref, swizzle, condition_swizzle);
list.push_tail(assign);
}
/* Put all of the new instructions in the IR stream before the old
* instruction.
*/
base_ir->insert_before(&list);
this->progress = true;
return new(base_ir) ir_dereference_variable(var);
}
ir_rvalue *
ir_vec_index_to_cond_assign_visitor::convert_vector_extract_to_cond_assign(ir_rvalue *ir)
{
ir_expression *const expr = ir->as_expression();
if (expr == NULL || expr->operation != ir_binop_vector_extract)
return ir;
return convert_vec_index_to_cond_assign(ralloc_parent(ir),
expr->operands[0],
expr->operands[1],
ir->type);
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_enter(ir_expression *ir)
{
unsigned int i;
for (i = 0; i < ir->get_num_operands(); i++) {
ir->operands[i] = convert_vector_extract_to_cond_assign(ir->operands[i]);
}
return visit_continue;
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_enter(ir_swizzle *ir)
{
/* Can't be hit from normal GLSL, since you can't swizzle a scalar (which
* the result of indexing a vector is. But maybe at some point we'll end up
* using swizzling of scalars for vector construction.
*/
ir->val = convert_vector_extract_to_cond_assign(ir->val);
return visit_continue;
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_leave(ir_assignment *ir)
{
ir->rhs = convert_vector_extract_to_cond_assign(ir->rhs);
if (ir->condition) {
ir->condition = convert_vector_extract_to_cond_assign(ir->condition);
}
return visit_continue;
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_enter(ir_call *ir)
{
foreach_iter(exec_list_iterator, iter, *ir) {
ir_rvalue *param = (ir_rvalue *)iter.get();
ir_rvalue *new_param = convert_vector_extract_to_cond_assign(param);
if (new_param != param) {
param->replace_with(new_param);
}
}
return visit_continue;
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_enter(ir_return *ir)
{
if (ir->value) {
ir->value = convert_vector_extract_to_cond_assign(ir->value);
}
return visit_continue;
}
ir_visitor_status
ir_vec_index_to_cond_assign_visitor::visit_enter(ir_if *ir)
{
ir->condition = convert_vector_extract_to_cond_assign(ir->condition);
return visit_continue;
}
bool
do_vec_index_to_cond_assign(exec_list *instructions)
{
ir_vec_index_to_cond_assign_visitor v;
visit_list_elements(&v, instructions);
return v.progress;
}