1 /* 2 * Copyright 2012 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 */ 23 24 #include "brw_fs.h" 25 #include "brw_fs_cfg.h" 26 27 namespace { /* avoid conflict with opt_copy_propagation_elements */ 28 struct acp_entry : public exec_node { 29 fs_reg dst; 30 fs_reg src; 31 }; 32 } 33 34 bool 35 fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry) 36 { 37 if (inst->src[arg].file != entry->dst.file || 38 inst->src[arg].reg != entry->dst.reg || 39 inst->src[arg].reg_offset != entry->dst.reg_offset) { 40 return false; 41 } 42 43 /* See resolve_ud_negate() and comment in brw_fs_emit.cpp. */ 44 if (inst->conditional_mod && 45 inst->src[arg].type == BRW_REGISTER_TYPE_UD && 46 entry->src.negate) 47 return false; 48 49 bool has_source_modifiers = entry->src.abs || entry->src.negate; 50 51 if (intel->gen == 6 && inst->is_math() && 52 (has_source_modifiers || entry->src.file == UNIFORM)) 53 return false; 54 55 inst->src[arg].file = entry->src.file; 56 inst->src[arg].reg = entry->src.reg; 57 inst->src[arg].reg_offset = entry->src.reg_offset; 58 59 if (!inst->src[arg].abs) { 60 inst->src[arg].abs = entry->src.abs; 61 inst->src[arg].negate ^= entry->src.negate; 62 } 63 64 return true; 65 } 66 67 /** @file brw_fs_copy_propagation.cpp 68 * 69 * Support for local copy propagation by walking the list of instructions 70 * and maintaining the ACP table of available copies for propagation. 71 * 72 * See Muchnik's Advanced Compiler Design and Implementation, section 73 * 12.5 (p356). 74 */ 75 76 /* Walks a basic block and does copy propagation on it using the acp 77 * list. 78 */ 79 bool 80 fs_visitor::opt_copy_propagate_local(void *mem_ctx, 81 fs_bblock *block, exec_list *acp) 82 { 83 bool progress = false; 84 85 for (fs_inst *inst = block->start; 86 inst != block->end->next; 87 inst = (fs_inst *)inst->next) { 88 89 /* Try propagating into this instruction. */ 90 foreach_list(entry_node, acp) { 91 acp_entry *entry = (acp_entry *)entry_node; 92 93 for (int i = 0; i < 3; i++) { 94 if (try_copy_propagate(inst, i, entry)) 95 progress = true; 96 } 97 } 98 99 /* kill the destination from the ACP */ 100 if (inst->dst.file == GRF) { 101 foreach_list_safe(entry_node, acp) { 102 acp_entry *entry = (acp_entry *)entry_node; 103 104 if (inst->overwrites_reg(entry->dst) || 105 inst->overwrites_reg(entry->src)) { 106 entry->remove(); 107 } 108 } 109 } 110 111 /* If this instruction is a raw copy, add it to the ACP. */ 112 if (inst->opcode == BRW_OPCODE_MOV && 113 inst->dst.file == GRF && 114 ((inst->src[0].file == GRF && 115 (inst->src[0].reg != inst->dst.reg || 116 inst->src[0].reg_offset != inst->dst.reg_offset)) || 117 inst->src[0].file == UNIFORM) && 118 inst->src[0].type == inst->dst.type && 119 !inst->saturate && 120 !inst->predicated && 121 !inst->force_uncompressed && 122 !inst->force_sechalf && 123 inst->src[0].smear == -1) { 124 acp_entry *entry = ralloc(mem_ctx, acp_entry); 125 entry->dst = inst->dst; 126 entry->src = inst->src[0]; 127 acp->push_tail(entry); 128 } 129 } 130 131 return progress; 132 } 133 134 bool 135 fs_visitor::opt_copy_propagate() 136 { 137 bool progress = false; 138 void *mem_ctx = ralloc_context(this->mem_ctx); 139 140 fs_cfg cfg(this); 141 142 for (int b = 0; b < cfg.num_blocks; b++) { 143 fs_bblock *block = cfg.blocks[b]; 144 exec_list acp; 145 146 progress = opt_copy_propagate_local(mem_ctx, block, &acp) || progress; 147 } 148 149 ralloc_free(mem_ctx); 150 151 if (progress) 152 live_intervals_valid = false; 153 154 return progress; 155 } 156
