src/panfrost/midgard/mir.c

   1 /*
   2  * Copyright (C) 2019 Alyssa Rosenzweig <alyssa@rosenzweig.io>
   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 FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  */
  23
  24 #include "compiler.h"
  25 #include "midgard_ops.h"
  26
  27 void mir_rewrite_index_src_single(midgard_instruction *ins, unsigned old, unsigned new)
  28 {
  29         if (ins->ssa_args.src0 == old)
  30                 ins->ssa_args.src0 = new;
  31
  32         if (ins->ssa_args.src1 == old &&
  33             !ins->ssa_args.inline_constant)
  34                 ins->ssa_args.src1 = new;
  35 }
  36
  37
  38 void
  39 mir_rewrite_index_src(compiler_context *ctx, unsigned old, unsigned new)
  40 {
  41         mir_foreach_instr_global(ctx, ins) {
  42                 mir_rewrite_index_src_single(ins, old, new);
  43         }
  44 }
  45
  46 void
  47 mir_rewrite_index_src_tag(compiler_context *ctx, unsigned old, unsigned new, unsigned tag)
  48 {
  49         mir_foreach_instr_global(ctx, ins) {
  50                 if (ins->type != tag)
  51                         continue;
  52
  53                 mir_rewrite_index_src_single(ins, old, new);
  54         }
  55 }
  56
  57
  58
  59 void
  60 mir_rewrite_index_dst(compiler_context *ctx, unsigned old, unsigned new)
  61 {
  62         mir_foreach_instr_global(ctx, ins) {
  63                 if (ins->ssa_args.dest == old)
  64                         ins->ssa_args.dest = new;
  65         }
  66 }
  67
  68 void
  69 mir_rewrite_index_dst_tag(compiler_context *ctx, unsigned old, unsigned new, unsigned tag)
  70 {
  71         mir_foreach_instr_global(ctx, ins) {
  72                 if (ins->type != tag)
  73                         continue;
  74
  75                 if (ins->ssa_args.dest == old)
  76                         ins->ssa_args.dest = new;
  77         }
  78 }
  79
  80
  81
  82 void
  83 mir_rewrite_index(compiler_context *ctx, unsigned old, unsigned new)
  84 {
  85         mir_rewrite_index_src(ctx, old, new);
  86         mir_rewrite_index_dst(ctx, old, new);
  87 }
  88
  89 unsigned
  90 mir_use_count(compiler_context *ctx, unsigned value)
  91 {
  92         unsigned used_count = 0;
  93
  94         mir_foreach_instr_global(ctx, ins) {
  95                 if (mir_has_arg(ins, value))
  96                         ++used_count;
  97         }
  98
  99         return used_count;
 100 }
 101
 102 /* Checks if a value is used only once (or totally dead), which is an important
 103  * heuristic to figure out if certain optimizations are Worth It (TM) */
 104
 105 bool
 106 mir_single_use(compiler_context *ctx, unsigned value)
 107 {
 108         return mir_use_count(ctx, value) <= 1;
 109 }
 110
 111 bool
 112 mir_nontrivial_raw_mod(midgard_vector_alu_src src, bool is_int)
 113 {
 114         if (is_int)
 115                 return src.mod == midgard_int_shift;
 116         else
 117                 return src.mod;
 118 }
 119
 120 bool
 121 mir_nontrivial_mod(midgard_vector_alu_src src, bool is_int, unsigned mask)
 122 {
 123         if (mir_nontrivial_raw_mod(src, is_int)) return true;
 124
 125         /* size-conversion */
 126         if (src.half) return true;
 127
 128         /* swizzle */
 129         for (unsigned c = 0; c < 4; ++c) {
 130                 if (!(mask & (1 << c))) continue;
 131                 if (((src.swizzle >> (2*c)) & 3) != c) return true;
 132         }
 133
 134         return false;
 135 }
 136 bool
 137 mir_nontrivial_source2_mod(midgard_instruction *ins)
 138 {
 139         bool is_int = midgard_is_integer_op(ins->alu.op);
 140
 141         midgard_vector_alu_src src2 =
 142                 vector_alu_from_unsigned(ins->alu.src2);
 143
 144         return mir_nontrivial_mod(src2, is_int, ins->mask);
 145 }
 146
 147 bool
 148 mir_nontrivial_outmod(midgard_instruction *ins)
 149 {
 150         bool is_int = midgard_is_integer_op(ins->alu.op);
 151         unsigned mod = ins->alu.outmod;
 152
 153         /* Pseudo-outmod */
 154         if (ins->invert)
 155                 return true;
 156
 157         /* Type conversion is a sort of outmod */
 158         if (ins->alu.dest_override != midgard_dest_override_none)
 159                 return true;
 160
 161         if (is_int)
 162                 return mod != midgard_outmod_int_wrap;
 163         else
 164                 return mod != midgard_outmod_none;
 165 }
 166
 167 /* Checks if an index will be used as a special register -- basically, if we're
 168  * used as the input to a non-ALU op */
 169
 170 bool
 171 mir_special_index(compiler_context *ctx, unsigned idx)
 172 {
 173         mir_foreach_instr_global(ctx, ins) {
 174                 bool is_ldst = ins->type == TAG_LOAD_STORE_4;
 175                 bool is_tex = ins->type == TAG_TEXTURE_4;
 176
 177                 if (!(is_ldst || is_tex))
 178                         continue;
 179
 180                 if (mir_has_arg(ins, idx))
 181                         return true;
 182         }
 183
 184         return false;
 185 }
 186
 187 /* Is a node written before a given instruction? */
 188
 189 bool
 190 mir_is_written_before(compiler_context *ctx, midgard_instruction *ins, unsigned node)
 191 {
 192         if ((node < 0) || (node >= SSA_FIXED_MINIMUM))
 193                 return true;
 194
 195         mir_foreach_instr_global(ctx, q) {
 196                 if (q == ins)
 197                         break;
 198
 199                 if (q->ssa_args.dest == node)
 200                         return true;
 201         }
 202
 203         return false;
 204 }
 205
 206 /* Creates a mask of the components of a node read by an instruction, by
 207  * analyzing the swizzle with respect to the instruction's mask. E.g.:
 208  *
 209  *  fadd r0.xz, r1.yyyy, r2.zwyx
 210  *
 211  * will return a mask of Z/Y for r2
 212  */
 213
 214 static unsigned
 215 mir_mask_of_read_components_single(unsigned src, unsigned outmask)
 216 {
 217         midgard_vector_alu_src s = vector_alu_from_unsigned(src);
 218         unsigned mask = 0;
 219
 220         for (unsigned c = 0; c < 4; ++c) {
 221                 if (!(outmask & (1 << c))) continue;
 222
 223                 unsigned comp = (s.swizzle >> (2*c)) & 3;
 224                 mask |= (1 << comp);
 225         }
 226
 227         return mask;
 228 }
 229
 230 unsigned
 231 mir_mask_of_read_components(midgard_instruction *ins, unsigned node)
 232 {
 233         assert(ins->type == TAG_ALU_4);
 234
 235         unsigned mask = 0;
 236
 237         if (ins->ssa_args.src0 == node)
 238                 mask |= mir_mask_of_read_components_single(ins->alu.src1, ins->mask);
 239
 240         if (ins->ssa_args.src1 == node && !ins->ssa_args.inline_constant)
 241                 mask |= mir_mask_of_read_components_single(ins->alu.src2, ins->mask);
 242
 243         return mask;
 244 }