src/broadcom/compiler/vir_opt_small_immediates.c

   1 /*
   2  * Copyright © 2014 Broadcom
   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 /**
  25  * @file v3d_opt_small_immediates.c
  26  *
  27  * Turns references to small constant uniform values into small immediates
  28  * fields.
  29  */
  30
  31 #include "v3d_compiler.h"
  32
  33 static bool debug;
  34
  35 bool
  36 vir_opt_small_immediates(struct v3d_compile *c)
  37 {
  38         bool progress = false;
  39
  40         vir_for_each_inst_inorder(inst, c) {
  41                 if (inst->qpu.type != V3D_QPU_INSTR_TYPE_ALU)
  42                         continue;
  43
  44                 /* The small immediate value sits in the raddr B field, so we
  45                  * can't have 2 small immediates in one instruction (unless
  46                  * they're the same value, but that should be optimized away
  47                  * elsewhere).
  48                  */
  49                 bool uses_small_imm = false;
  50                 for (int i = 0; i < vir_get_nsrc(inst); i++) {
  51                         if (inst->src[i].file == QFILE_SMALL_IMM)
  52                                 uses_small_imm = true;
  53                 }
  54                 if (uses_small_imm)
  55                         continue;
  56
  57                 for (int i = 0; i < vir_get_nsrc(inst); i++) {
  58                         if (inst->src[i].file != QFILE_TEMP)
  59                                 continue;
  60
  61                         /* See if it's a uniform load. */
  62                         struct qinst *src_def = c->defs[inst->src[i].index];
  63                         if (!src_def || !src_def->qpu.sig.ldunif)
  64                                 continue;
  65                         int uniform = src_def->uniform;
  66
  67                         if (c->uniform_contents[uniform] != QUNIFORM_CONSTANT)
  68                                 continue;
  69
  70                         /* Check if the uniform is suitable as a small
  71                          * immediate.
  72                          */
  73                         uint32_t imm = c->uniform_data[uniform];
  74                         uint32_t packed;
  75                         if (!v3d_qpu_small_imm_pack(c->devinfo, imm, &packed))
  76                                 continue;
  77
  78                         /* Check that we don't have any other signals already
  79                          * that would be incompatible with small_imm.
  80                          */
  81                         struct v3d_qpu_sig new_sig = inst->qpu.sig;
  82                         uint32_t sig_packed;
  83                         new_sig.small_imm = true;
  84                         if (!v3d_qpu_sig_pack(c->devinfo, &new_sig, &sig_packed))
  85                                 continue;
  86
  87                         if (debug) {
  88                                 fprintf(stderr, "opt_small_immediate() from: ");
  89                                 vir_dump_inst(c, inst);
  90                                 fprintf(stderr, "\n");
  91                         }
  92                         inst->qpu.sig.small_imm = true;
  93                         inst->qpu.raddr_b = packed;
  94
  95                         inst->src[i].file = QFILE_SMALL_IMM;
  96                         inst->src[i].index = imm;
  97                         if (debug) {
  98                                 fprintf(stderr, "to: ");
  99                                 vir_dump_inst(c, inst);
 100                                 fprintf(stderr, "\n");
 101                         }
 102                         progress = true;
 103                         break;
 104                 }
 105         }
 106
 107         return progress;
 108 }