11591693c7b415e9869157c711fe11263c95d74eDavid Li/* 21591693c7b415e9869157c711fe11263c95d74eDavid Li * Copyright © 2010 Intel Corporation 31591693c7b415e9869157c711fe11263c95d74eDavid Li * 41591693c7b415e9869157c711fe11263c95d74eDavid Li * Permission is hereby granted, free of charge, to any person obtaining a 51591693c7b415e9869157c711fe11263c95d74eDavid Li * copy of this software and associated documentation files (the "Software"), 61591693c7b415e9869157c711fe11263c95d74eDavid Li * to deal in the Software without restriction, including without limitation 71591693c7b415e9869157c711fe11263c95d74eDavid Li * the rights to use, copy, modify, merge, publish, distribute, sublicense, 81591693c7b415e9869157c711fe11263c95d74eDavid Li * and/or sell copies of the Software, and to permit persons to whom the 91591693c7b415e9869157c711fe11263c95d74eDavid Li * Software is furnished to do so, subject to the following conditions: 101591693c7b415e9869157c711fe11263c95d74eDavid Li * 111591693c7b415e9869157c711fe11263c95d74eDavid Li * The above copyright notice and this permission notice (including the next 121591693c7b415e9869157c711fe11263c95d74eDavid Li * paragraph) shall be included in all copies or substantial portions of the 131591693c7b415e9869157c711fe11263c95d74eDavid Li * Software. 141591693c7b415e9869157c711fe11263c95d74eDavid Li * 151591693c7b415e9869157c711fe11263c95d74eDavid Li * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 161591693c7b415e9869157c711fe11263c95d74eDavid Li * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 171591693c7b415e9869157c711fe11263c95d74eDavid Li * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 181591693c7b415e9869157c711fe11263c95d74eDavid Li * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 191591693c7b415e9869157c711fe11263c95d74eDavid Li * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 201591693c7b415e9869157c711fe11263c95d74eDavid Li * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 211591693c7b415e9869157c711fe11263c95d74eDavid Li * DEALINGS IN THE SOFTWARE. 221591693c7b415e9869157c711fe11263c95d74eDavid Li */ 231591693c7b415e9869157c711fe11263c95d74eDavid Li 241591693c7b415e9869157c711fe11263c95d74eDavid Li/** 251591693c7b415e9869157c711fe11263c95d74eDavid Li * \file lower_discard.cpp 261591693c7b415e9869157c711fe11263c95d74eDavid Li * 271591693c7b415e9869157c711fe11263c95d74eDavid Li * This pass moves discards out of if-statements. 281591693c7b415e9869157c711fe11263c95d74eDavid Li * 291591693c7b415e9869157c711fe11263c95d74eDavid Li * Case 1: The "then" branch contains a conditional discard: 301591693c7b415e9869157c711fe11263c95d74eDavid Li * --------------------------------------------------------- 311591693c7b415e9869157c711fe11263c95d74eDavid Li * 321591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 331591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 341591693c7b415e9869157c711fe11263c95d74eDavid Li * discard cond2; 351591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 361591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 371591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 381591693c7b415e9869157c711fe11263c95d74eDavid Li * } 391591693c7b415e9869157c711fe11263c95d74eDavid Li * 401591693c7b415e9869157c711fe11263c95d74eDavid Li * becomes: 411591693c7b415e9869157c711fe11263c95d74eDavid Li * 421591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = false; 431591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 441591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 451591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = cond2; 461591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 471591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 481591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 491591693c7b415e9869157c711fe11263c95d74eDavid Li * } 501591693c7b415e9869157c711fe11263c95d74eDavid Li * discard temp; 511591693c7b415e9869157c711fe11263c95d74eDavid Li * 521591693c7b415e9869157c711fe11263c95d74eDavid Li * Case 2: The "else" branch contains a conditional discard: 531591693c7b415e9869157c711fe11263c95d74eDavid Li * --------------------------------------------------------- 541591693c7b415e9869157c711fe11263c95d74eDavid Li * 551591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 561591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 571591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 581591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 591591693c7b415e9869157c711fe11263c95d74eDavid Li * discard cond2; 601591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 611591693c7b415e9869157c711fe11263c95d74eDavid Li * } 621591693c7b415e9869157c711fe11263c95d74eDavid Li * 631591693c7b415e9869157c711fe11263c95d74eDavid Li * becomes: 641591693c7b415e9869157c711fe11263c95d74eDavid Li * 651591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = false; 661591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 671591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 681591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 691591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 701591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = cond2; 711591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 721591693c7b415e9869157c711fe11263c95d74eDavid Li * } 731591693c7b415e9869157c711fe11263c95d74eDavid Li * discard temp; 741591693c7b415e9869157c711fe11263c95d74eDavid Li * 751591693c7b415e9869157c711fe11263c95d74eDavid Li * Case 3: Both branches contain a conditional discard: 761591693c7b415e9869157c711fe11263c95d74eDavid Li * ---------------------------------------------------- 771591693c7b415e9869157c711fe11263c95d74eDavid Li * 781591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 791591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 801591693c7b415e9869157c711fe11263c95d74eDavid Li * discard cond2; 811591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 821591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 831591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 841591693c7b415e9869157c711fe11263c95d74eDavid Li * discard cond3; 851591693c7b415e9869157c711fe11263c95d74eDavid Li * s4; 861591693c7b415e9869157c711fe11263c95d74eDavid Li * } 871591693c7b415e9869157c711fe11263c95d74eDavid Li * 881591693c7b415e9869157c711fe11263c95d74eDavid Li * becomes: 891591693c7b415e9869157c711fe11263c95d74eDavid Li * 901591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = false; 911591693c7b415e9869157c711fe11263c95d74eDavid Li * if (cond1) { 921591693c7b415e9869157c711fe11263c95d74eDavid Li * s1; 931591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = cond2; 941591693c7b415e9869157c711fe11263c95d74eDavid Li * s2; 951591693c7b415e9869157c711fe11263c95d74eDavid Li * } else { 961591693c7b415e9869157c711fe11263c95d74eDavid Li * s3; 971591693c7b415e9869157c711fe11263c95d74eDavid Li * temp = cond3; 981591693c7b415e9869157c711fe11263c95d74eDavid Li * s4; 991591693c7b415e9869157c711fe11263c95d74eDavid Li * } 1001591693c7b415e9869157c711fe11263c95d74eDavid Li * discard temp; 1011591693c7b415e9869157c711fe11263c95d74eDavid Li * 1021591693c7b415e9869157c711fe11263c95d74eDavid Li * If there are multiple conditional discards, we need only deal with one of 1031591693c7b415e9869157c711fe11263c95d74eDavid Li * them. Repeatedly applying this pass will take care of the others. 1041591693c7b415e9869157c711fe11263c95d74eDavid Li * 1051591693c7b415e9869157c711fe11263c95d74eDavid Li * Unconditional discards are treated as having a condition of "true". 1061591693c7b415e9869157c711fe11263c95d74eDavid Li */ 1071591693c7b415e9869157c711fe11263c95d74eDavid Li 1081591693c7b415e9869157c711fe11263c95d74eDavid Li#include "glsl_types.h" 1091591693c7b415e9869157c711fe11263c95d74eDavid Li#include "ir.h" 1101591693c7b415e9869157c711fe11263c95d74eDavid Li 1111591693c7b415e9869157c711fe11263c95d74eDavid Liclass lower_discard_visitor : public ir_hierarchical_visitor { 1121591693c7b415e9869157c711fe11263c95d74eDavid Lipublic: 1131591693c7b415e9869157c711fe11263c95d74eDavid Li lower_discard_visitor() 1141591693c7b415e9869157c711fe11263c95d74eDavid Li { 1151591693c7b415e9869157c711fe11263c95d74eDavid Li this->progress = false; 1161591693c7b415e9869157c711fe11263c95d74eDavid Li } 1171591693c7b415e9869157c711fe11263c95d74eDavid Li 1181591693c7b415e9869157c711fe11263c95d74eDavid Li ir_visitor_status visit_leave(ir_if *); 1191591693c7b415e9869157c711fe11263c95d74eDavid Li 1201591693c7b415e9869157c711fe11263c95d74eDavid Li bool progress; 1211591693c7b415e9869157c711fe11263c95d74eDavid Li}; 1221591693c7b415e9869157c711fe11263c95d74eDavid Li 1231591693c7b415e9869157c711fe11263c95d74eDavid Li 1241591693c7b415e9869157c711fe11263c95d74eDavid Libool 1251591693c7b415e9869157c711fe11263c95d74eDavid Lilower_discard(exec_list *instructions) 1261591693c7b415e9869157c711fe11263c95d74eDavid Li{ 1271591693c7b415e9869157c711fe11263c95d74eDavid Li lower_discard_visitor v; 1281591693c7b415e9869157c711fe11263c95d74eDavid Li 1291591693c7b415e9869157c711fe11263c95d74eDavid Li visit_list_elements(&v, instructions); 1301591693c7b415e9869157c711fe11263c95d74eDavid Li 1311591693c7b415e9869157c711fe11263c95d74eDavid Li return v.progress; 1321591693c7b415e9869157c711fe11263c95d74eDavid Li} 1331591693c7b415e9869157c711fe11263c95d74eDavid Li 1341591693c7b415e9869157c711fe11263c95d74eDavid Li 1351591693c7b415e9869157c711fe11263c95d74eDavid Listatic ir_discard * 1361591693c7b415e9869157c711fe11263c95d74eDavid Lifind_discard(exec_list &instructions) 1371591693c7b415e9869157c711fe11263c95d74eDavid Li{ 1381591693c7b415e9869157c711fe11263c95d74eDavid Li foreach_list(n, &instructions) { 1391591693c7b415e9869157c711fe11263c95d74eDavid Li ir_discard *ir = ((ir_instruction *) n)->as_discard(); 1401591693c7b415e9869157c711fe11263c95d74eDavid Li if (ir != NULL) 1411591693c7b415e9869157c711fe11263c95d74eDavid Li return ir; 1421591693c7b415e9869157c711fe11263c95d74eDavid Li } 1431591693c7b415e9869157c711fe11263c95d74eDavid Li return NULL; 1441591693c7b415e9869157c711fe11263c95d74eDavid Li} 1451591693c7b415e9869157c711fe11263c95d74eDavid Li 1461591693c7b415e9869157c711fe11263c95d74eDavid Li 1471591693c7b415e9869157c711fe11263c95d74eDavid Listatic void 1481591693c7b415e9869157c711fe11263c95d74eDavid Lireplace_discard(void *mem_ctx, ir_variable *var, ir_discard *ir) 1491591693c7b415e9869157c711fe11263c95d74eDavid Li{ 1501591693c7b415e9869157c711fe11263c95d74eDavid Li ir_rvalue *condition = ir->condition; 1511591693c7b415e9869157c711fe11263c95d74eDavid Li 1521591693c7b415e9869157c711fe11263c95d74eDavid Li /* For unconditional discards, use "true" as the condition. */ 1531591693c7b415e9869157c711fe11263c95d74eDavid Li if (condition == NULL) 1541591693c7b415e9869157c711fe11263c95d74eDavid Li condition = new(mem_ctx) ir_constant(true); 1551591693c7b415e9869157c711fe11263c95d74eDavid Li 1561591693c7b415e9869157c711fe11263c95d74eDavid Li ir_assignment *assignment = 1571591693c7b415e9869157c711fe11263c95d74eDavid Li new(mem_ctx) ir_assignment(new(mem_ctx) ir_dereference_variable(var), 1581591693c7b415e9869157c711fe11263c95d74eDavid Li condition, NULL); 1591591693c7b415e9869157c711fe11263c95d74eDavid Li 1601591693c7b415e9869157c711fe11263c95d74eDavid Li ir->replace_with(assignment); 1611591693c7b415e9869157c711fe11263c95d74eDavid Li} 1621591693c7b415e9869157c711fe11263c95d74eDavid Li 1631591693c7b415e9869157c711fe11263c95d74eDavid Li 1641591693c7b415e9869157c711fe11263c95d74eDavid Liir_visitor_status 1651591693c7b415e9869157c711fe11263c95d74eDavid Lilower_discard_visitor::visit_leave(ir_if *ir) 1661591693c7b415e9869157c711fe11263c95d74eDavid Li{ 1671591693c7b415e9869157c711fe11263c95d74eDavid Li ir_discard *then_discard = find_discard(ir->then_instructions); 1681591693c7b415e9869157c711fe11263c95d74eDavid Li ir_discard *else_discard = find_discard(ir->else_instructions); 1691591693c7b415e9869157c711fe11263c95d74eDavid Li 1701591693c7b415e9869157c711fe11263c95d74eDavid Li if (then_discard == NULL && else_discard == NULL) 1711591693c7b415e9869157c711fe11263c95d74eDavid Li return visit_continue; 1721591693c7b415e9869157c711fe11263c95d74eDavid Li 173d50d9a90a0df4d706421850e17c0fbd85bf710eeDavid Li void *mem_ctx = hieralloc_parent(ir); 1741591693c7b415e9869157c711fe11263c95d74eDavid Li 1751591693c7b415e9869157c711fe11263c95d74eDavid Li ir_variable *temp = new(mem_ctx) ir_variable(glsl_type::bool_type, 1761591693c7b415e9869157c711fe11263c95d74eDavid Li "discard_cond_temp", 1771591693c7b415e9869157c711fe11263c95d74eDavid Li ir_var_temporary); 1781591693c7b415e9869157c711fe11263c95d74eDavid Li ir_assignment *temp_initializer = 1791591693c7b415e9869157c711fe11263c95d74eDavid Li new(mem_ctx) ir_assignment(new(mem_ctx) ir_dereference_variable(temp), 1801591693c7b415e9869157c711fe11263c95d74eDavid Li new(mem_ctx) ir_constant(false), NULL); 1811591693c7b415e9869157c711fe11263c95d74eDavid Li 1821591693c7b415e9869157c711fe11263c95d74eDavid Li ir->insert_before(temp); 1831591693c7b415e9869157c711fe11263c95d74eDavid Li ir->insert_before(temp_initializer); 1841591693c7b415e9869157c711fe11263c95d74eDavid Li 1851591693c7b415e9869157c711fe11263c95d74eDavid Li if (then_discard != NULL) 1861591693c7b415e9869157c711fe11263c95d74eDavid Li replace_discard(mem_ctx, temp, then_discard); 1871591693c7b415e9869157c711fe11263c95d74eDavid Li 1881591693c7b415e9869157c711fe11263c95d74eDavid Li if (else_discard != NULL) 1891591693c7b415e9869157c711fe11263c95d74eDavid Li replace_discard(mem_ctx, temp, else_discard); 1901591693c7b415e9869157c711fe11263c95d74eDavid Li 1911591693c7b415e9869157c711fe11263c95d74eDavid Li ir_discard *discard = then_discard != NULL ? then_discard : else_discard; 1921591693c7b415e9869157c711fe11263c95d74eDavid Li discard->condition = new(mem_ctx) ir_dereference_variable(temp); 1931591693c7b415e9869157c711fe11263c95d74eDavid Li ir->insert_after(discard); 1941591693c7b415e9869157c711fe11263c95d74eDavid Li 1951591693c7b415e9869157c711fe11263c95d74eDavid Li this->progress = true; 1961591693c7b415e9869157c711fe11263c95d74eDavid Li 1971591693c7b415e9869157c711fe11263c95d74eDavid Li return visit_continue; 1981591693c7b415e9869157c711fe11263c95d74eDavid Li} 199