src/panfrost/midgard/midgard_opt_copy_prop.c

   1 /*
   2  * Copyright (C) 2018 Alyssa Rosenzweig
   3  * Copyright (C) 2019 Collabora, Ltd.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include "compiler.h"
  26 #include "midgard_ops.h"
  27
  28 bool
  29 midgard_opt_copy_prop(compiler_context *ctx, midgard_block *block)
  30 {
  31         bool progress = false;
  32
  33         mir_foreach_instr_in_block_safe(block, ins) {
  34                 if (ins->type != TAG_ALU_4) continue;
  35                 if (!OP_IS_MOVE(ins->alu.op)) continue;
  36
  37                 unsigned from = ins->src[1];
  38                 unsigned to = ins->dest;
  39
  40                 /* We only work on pure SSA */
  41
  42                 if (to >= SSA_FIXED_MINIMUM) continue;
  43                 if (from >= SSA_FIXED_MINIMUM) continue;
  44                 if (to & IS_REG) continue;
  45                 if (from & IS_REG) continue;
  46
  47                 /* Constant propagation is not handled here, either */
  48                 if (ins->has_inline_constant) continue;
  49                 if (ins->has_constants) continue;
  50
  51                 /* Modifier propagation is not handled here */
  52                 if (mir_nontrivial_source2_mod_simple(ins)) continue;
  53                 if (mir_nontrivial_outmod(ins)) continue;
  54
  55                 /* Shortened arguments (bias for textures, extra load/store
  56                  * arguments, etc.) do not get a swizzle, only a start
  57                  * component and even that is restricted. Fragment writeout
  58                  * doesn't even get that much */
  59
  60                 bool skip = false;
  61
  62                 mir_foreach_instr_global(ctx, q) {
  63                         bool is_tex = q->type == TAG_TEXTURE_4;
  64                         bool is_ldst = q->type == TAG_LOAD_STORE_4;
  65                         bool is_writeout = q->compact_branch && q->writeout;
  66
  67                         if (!(is_tex || is_ldst || is_writeout)) continue;
  68
  69                         /* For textures, we get one real swizzle. For stores,
  70                          * we also get one. For loads, we get none. */
  71
  72                         unsigned start =
  73                                 is_tex ? 1 :
  74                                 OP_IS_STORE(q->load_store.op) ? 1 : 0;
  75
  76                         mir_foreach_src(q, s) {
  77                                 if ((s >= start) && q->src[s] == to) {
  78                                         skip = true;
  79                                         break;
  80                                 }
  81                         }
  82                 }
  83
  84                 if (skip)
  85                         continue;
  86
  87                 /* We're clear -- rewrite, composing the swizzle */
  88                 midgard_vector_alu_src src2 =
  89                         vector_alu_from_unsigned(ins->alu.src2);
  90
  91                 mir_rewrite_index_src_swizzle(ctx, to, from, src2.swizzle);
  92                 mir_remove_instruction(ins);
  93                 progress |= true;
  94         }
  95
  96         return progress;
  97 }