src/gallium/drivers/freedreno/a2xx/ir2_cp.c

   1 /*
   2  * Copyright (C) 2018 Jonathan Marek <jonathan@marek.ca>
   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  * Authors:
  24  *    Jonathan Marek <jonathan@marek.ca>
  25  */
  26
  27 #include "ir2_private.h"
  28
  29 static bool is_mov(struct ir2_instr *instr)
  30 {
  31         return instr->type == IR2_ALU && instr->alu.vector_opc == MAXv &&
  32                 instr->src_count == 1;
  33 }
  34
  35 static void src_combine(struct ir2_src *src, struct ir2_src b)
  36 {
  37         src->num = b.num;
  38         src->type = b.type;
  39         src->swizzle = swiz_merge(b.swizzle, src->swizzle);
  40         if (!src->abs) /* if we have abs we don't care about previous negate */
  41                 src->negate ^= b.negate;
  42         src->abs |= b.abs;
  43 }
  44
  45 /* cp_src: replace src regs when they refer to a mov instruction
  46  * example:
  47  *      ALU:      MAXv    R7 = C7, C7
  48  *      ALU:      MULADDv R7 = R7, R10, R0.xxxx
  49  * becomes:
  50  *      ALU:      MULADDv R7 = C7, R10, R0.xxxx
  51  */
  52 void cp_src(struct ir2_context *ctx)
  53 {
  54         struct ir2_instr *p;
  55
  56         ir2_foreach_instr(instr, ctx) {
  57                 ir2_foreach_src(src, instr) {
  58                         /* loop to replace recursively */
  59                         do {
  60                                 if (src->type != IR2_SRC_SSA)
  61                                         break;
  62
  63                                 p = &ctx->instr[src->num];
  64                                 /* don't work across blocks to avoid possible issues */
  65                                 if (p->block_idx != instr->block_idx)
  66                                         break;
  67
  68                                 if (!is_mov(p))
  69                                         break;
  70
  71                                 /* cant apply abs to const src, const src only for alu */
  72                                 if (p->src[0].type == IR2_SRC_CONST &&
  73                                         (src->abs || instr->type != IR2_ALU))
  74                                         break;
  75
  76                                 src_combine(src, p->src[0]);
  77                         } while (1);
  78                 }
  79         }
  80 }
  81
  82 /* cp_export: replace mov to export when possible
  83  * in the cp_src pass we bypass any mov instructions related
  84  * to the src registers, but for exports for need something different
  85  * example:
  86  *      ALU:      MAXv    R3.x___ = C9.x???, C9.x???
  87  *      ALU:      MAXv    R3._y__ = R0.?x??, C8.?x??
  88  *      ALU:      MAXv    export0 = R3.yyyx, R3.yyyx
  89  * becomes:
  90  *      ALU:      MAXv    export0.___w = C9.???x, C9.???x
  91  *      ALU:      MAXv    export0.xyz_ = R0.xxx?, C8.xxx?
  92  *
  93  */
  94 void cp_export(struct ir2_context *ctx)
  95 {
  96         struct ir2_instr *c[4], *ins[4];
  97         struct ir2_src *src;
  98         struct ir2_reg *reg;
  99         unsigned ncomp;
 100
 101         ir2_foreach_instr(instr, ctx) {
 102                 if (!is_export(instr)) /* TODO */
 103                         continue;
 104
 105                 if (!is_mov(instr))
 106                         continue;
 107
 108                 src = &instr->src[0];
 109
 110                 if (src->negate || src->abs) /* TODO handle these cases */
 111                         continue;
 112
 113                 if (src->type == IR2_SRC_INPUT || src->type == IR2_SRC_CONST)
 114                         continue;
 115
 116                 reg = get_reg_src(ctx, src);
 117                 ncomp = dst_ncomp(instr);
 118
 119                 unsigned reswiz[4] = {};
 120                 unsigned num_instr = 0;
 121
 122                 /* fill array c with pointers to instrs that write each component */
 123                 if (src->type == IR2_SRC_SSA) {
 124                         struct ir2_instr *instr = &ctx->instr[src->num];
 125
 126                         if (instr->type != IR2_ALU)
 127                                 continue;
 128
 129                         for (int i = 0; i < ncomp; i++)
 130                                 c[i] = instr;
 131
 132                         ins[num_instr++] = instr;
 133                         reswiz[0] = src->swizzle;
 134                 } else {
 135                         bool ok = true;
 136                         unsigned write_mask = 0;
 137
 138                         ir2_foreach_instr(instr, ctx) {
 139                                 if (instr->is_ssa || instr->reg != reg)
 140                                         continue;
 141
 142                                 /* set by non-ALU */
 143                                 if (instr->type != IR2_ALU) {
 144                                         ok = false;
 145                                         break;
 146                                 }
 147
 148                                 /* component written more than once */
 149                                 if (write_mask & instr->alu.write_mask) {
 150                                         ok = false;
 151                                         break;
 152                                 }
 153
 154                                 write_mask |= instr->alu.write_mask;
 155
 156                                 /* src pointers for components */
 157                                 for (int i = 0, j = 0; i < 4; i++) {
 158                                         unsigned k = swiz_get(src->swizzle, i);
 159                                         if (instr->alu.write_mask & 1 << k) {
 160                                                 c[i] = instr;
 161
 162                                                 /* reswiz = compressed src->swizzle */
 163                                                 unsigned x = 0;
 164                                                 for (int i = 0; i < k; i++)
 165                                                         x += !!(instr->alu.write_mask & 1 << i);
 166
 167                                                 assert(src->swizzle || x == j);
 168                                                 reswiz[num_instr] |= swiz_set(x, j++);
 169                                         }
 170                                 }
 171                                 ins[num_instr++] = instr;
 172                         }
 173                         if (!ok)
 174                                 continue;
 175                 }
 176
 177                 bool redirect = true;
 178
 179                 /* must all be in same block */
 180                 for (int i = 0; i < ncomp; i++)
 181                         redirect &= (c[i]->block_idx == instr->block_idx);
 182
 183                 /* no other instr using the value */
 184                 ir2_foreach_instr(p, ctx) {
 185                         if (p == instr)
 186                                 continue;
 187                         ir2_foreach_src(src, p)
 188                                 redirect &= reg != get_reg_src(ctx, src);
 189                 }
 190
 191                 if (!redirect)
 192                         continue;
 193
 194                 /* redirect the instructions writing to the register */
 195                 for (int i = 0; i < num_instr; i++) {
 196                         struct ir2_instr *p = ins[i];
 197
 198                         p->alu.export = instr->alu.export;
 199                         p->alu.write_mask = 0;
 200                         p->is_ssa = true;
 201                         p->ssa.ncomp = 0;
 202                         memset(p->ssa.comp, 0, sizeof(p->ssa.comp));
 203
 204                         switch (instr->alu.vector_opc) {
 205                         case PRED_SETE_PUSHv ... PRED_SETGTE_PUSHv:
 206                         case DOT2ADDv:
 207                         case DOT3v:
 208                         case DOT4v:
 209                         case CUBEv:
 210                                 continue;
 211                         default:
 212                                 break;
 213                         }
 214                         ir2_foreach_src(s, p)
 215                                 swiz_merge_p(&s->swizzle, reswiz[i]);
 216                 }
 217
 218                 for (int i = 0; i < ncomp; i++) {
 219                         c[i]->alu.write_mask |= (1 << i);
 220                         c[i]->ssa.ncomp++;
 221                 }
 222                 instr->type = IR2_NONE;
 223                 instr->need_emit = false;
 224         }
 225 }