1 /* 2 * Copyright 2016 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 21 * DEALINGS IN THE SOFTWARE. 22 */ 23 24 #include "nir.h" 25 26 static void 27 add_src(nir_src *src, struct set *invariants) 28 { 29 if (src->is_ssa) { 30 _mesa_set_add(invariants, src->ssa); 31 } else { 32 _mesa_set_add(invariants, src->reg.reg); 33 } 34 } 35 36 static bool 37 add_src_cb(nir_src *src, void *state) 38 { 39 add_src(src, state); 40 return true; 41 } 42 43 static bool 44 dest_is_invariant(nir_dest *dest, struct set *invariants) 45 { 46 if (dest->is_ssa) { 47 return _mesa_set_search(invariants, &dest->ssa); 48 } else { 49 return _mesa_set_search(invariants, dest->reg.reg); 50 } 51 } 52 53 static void 54 add_cf_node(nir_cf_node *cf, struct set *invariants) 55 { 56 if (cf->type == nir_cf_node_if) { 57 nir_if *if_stmt = nir_cf_node_as_if(cf); 58 add_src(&if_stmt->condition, invariants); 59 } 60 61 if (cf->parent) 62 add_cf_node(cf->parent, invariants); 63 } 64 65 static void 66 add_var(nir_variable *var, struct set *invariants) 67 { 68 _mesa_set_add(invariants, var); 69 } 70 71 static bool 72 var_is_invariant(nir_variable *var, struct set * invariants) 73 { 74 return var->data.invariant || _mesa_set_search(invariants, var); 75 } 76 77 static void 78 propagate_invariant_instr(nir_instr *instr, struct set *invariants) 79 { 80 switch (instr->type) { 81 case nir_instr_type_alu: { 82 nir_alu_instr *alu = nir_instr_as_alu(instr); 83 if (!dest_is_invariant(&alu->dest.dest, invariants)) 84 break; 85 86 alu->exact = true; 87 nir_foreach_src(instr, add_src_cb, invariants); 88 break; 89 } 90 91 case nir_instr_type_tex: { 92 nir_tex_instr *tex = nir_instr_as_tex(instr); 93 if (dest_is_invariant(&tex->dest, invariants)) 94 nir_foreach_src(instr, add_src_cb, invariants); 95 break; 96 } 97 98 case nir_instr_type_intrinsic: { 99 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); 100 switch (intrin->intrinsic) { 101 case nir_intrinsic_copy_var: 102 /* If the destination is invariant then so is the source */ 103 if (var_is_invariant(intrin->variables[0]->var, invariants)) 104 add_var(intrin->variables[1]->var, invariants); 105 break; 106 107 case nir_intrinsic_load_var: 108 if (dest_is_invariant(&intrin->dest, invariants)) 109 add_var(intrin->variables[0]->var, invariants); 110 break; 111 112 case nir_intrinsic_store_var: 113 if (var_is_invariant(intrin->variables[0]->var, invariants)) 114 add_src(&intrin->src[0], invariants); 115 break; 116 117 default: 118 /* Nothing to do */ 119 break; 120 } 121 } 122 123 case nir_instr_type_jump: 124 case nir_instr_type_ssa_undef: 125 case nir_instr_type_load_const: 126 break; /* Nothing to do */ 127 128 case nir_instr_type_phi: { 129 nir_phi_instr *phi = nir_instr_as_phi(instr); 130 if (!dest_is_invariant(&phi->dest, invariants)) 131 break; 132 133 nir_foreach_phi_src(src, phi) { 134 add_src(&src->src, invariants); 135 add_cf_node(&src->pred->cf_node, invariants); 136 } 137 break; 138 } 139 140 case nir_instr_type_call: 141 unreachable("This pass must be run after function inlining"); 142 143 case nir_instr_type_parallel_copy: 144 default: 145 unreachable("Cannot have this instruction type"); 146 } 147 } 148 149 static bool 150 propagate_invariant_impl(nir_function_impl *impl, struct set *invariants) 151 { 152 bool progress = false; 153 154 while (true) { 155 uint32_t prev_entries = invariants->entries; 156 157 nir_foreach_block_reverse(block, impl) { 158 nir_foreach_instr_reverse(instr, block) 159 propagate_invariant_instr(instr, invariants); 160 } 161 162 /* Keep running until we make no more progress. */ 163 if (invariants->entries > prev_entries) { 164 progress = true; 165 continue; 166 } else { 167 break; 168 } 169 } 170 171 if (progress) { 172 nir_metadata_preserve(impl, nir_metadata_block_index | 173 nir_metadata_dominance | 174 nir_metadata_live_ssa_defs); 175 } 176 177 return progress; 178 } 179 180 bool 181 nir_propagate_invariant(nir_shader *shader) 182 { 183 /* Hash set of invariant things */ 184 struct set *invariants = _mesa_set_create(NULL, _mesa_hash_pointer, 185 _mesa_key_pointer_equal); 186 187 bool progress = false; 188 nir_foreach_function(function, shader) { 189 if (function->impl && propagate_invariant_impl(function->impl, invariants)) 190 progress = true; 191 } 192 193 _mesa_set_destroy(invariants, NULL); 194 195 return progress; 196 } 197