/*
 * Copyright 2013 Vadim Girlin <vadimgirlin@gmail.com>
 *
 * 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHOR(S) AND/OR THEIR SUPPLIERS 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:
 *      Vadim Girlin
 */

#define IFC_DEBUG 0

#if IFC_DEBUG
#define IFC_DUMP(q) do { q } while (0)
#else
#define IFC_DUMP(q)
#endif

#include "sb_shader.h"

#include "sb_pass.h"
#include "sb_if_conversion.h"

namespace r600_sb {

using std::cerr;


int r600_sb::if_conversion::run() {

	regions_vec &rv = sh.get_regions();

	unsigned converted = 0;

	for (regions_vec::reverse_iterator N, I = rv.rbegin(), E = rv.rend();
			I != E; I = N) {
		N = I; ++N;

		region_node *r = *I;
		if (run_on(r)) {
			rv.erase(I.base() - 1);
			++converted;
		}
	}

	return 0;
}

bool r600_sb::if_conversion::run_on(region_node* r) {

	if (!r->phi)
		return false;

	if (r->dep_count() != 2 || r->rep_count() != 1)
		return false;

	node_stats s;

	r->collect_stats(s);

	IFC_DUMP(
		cerr << "ifcvt: region " << r->region_id << " :\n";
		s.dump();
	);

	if (s.alu_kill_count || s.region_count || s.fetch_count ||
			s.if_count != 1 || s.repeat_count)
		return false;

	if (s.alu_count > 32)
		return false;


	depart_node *nd1 = static_cast<depart_node*>(r->first);
	if (!nd1->is_depart())
		return false;
	if_node *nif = static_cast<if_node*>(nd1->first);
	if (!nif->is_if())
		return false;
	depart_node *nd2 = static_cast<depart_node*>(nif->first);
	if (!nd2->is_depart())
		return false;

	value *em = nif->cond;
	value *select = get_select_value_for_em(sh, em);

	if (!select)
		return false;

	for (node_iterator I = r->phi->begin(), E = r->phi->end(); I != E; ++I) {
		node *n = *I;

		alu_node *ns = convert_phi(select, n);

		if (ns)
			r->insert_after(ns);
	}

	nd2->expand();
	nif->expand();
	nd1->expand();
	r->expand();

	return true;
}

alu_node* if_conversion::convert_phi(value* select, node* phi) {
	assert(phi->dst.size() == 1 || phi->src.size() == 2);

	value *d = phi->dst[0];
	value *v1 = phi->src[0];
	value *v2 = phi->src[1];

	assert(d);

	if (!d->is_any_gpr())
		return NULL;

	if (v1->is_undef()) {
		if (v2->is_undef()) {
			return NULL;
		} else {
			return sh.create_mov(d, v2);
		}
	} else if (v2->is_undef())
		return sh.create_mov(d, v1);

	alu_node* n = sh.create_alu();

	n->bc.set_op(ALU_OP3_CNDE_INT);
	n->dst.push_back(d);
	n->src.push_back(select);
	n->src.push_back(v1);
	n->src.push_back(v2);

	return n;
}

} // namespace r600_sb