src/mesa/drivers/dri/i965/brw_fs_lower_d2x.cpp

   1 /*
   2  * Copyright © 2015 Connor Abbott
   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 #include "brw_fs.h"
  25 #include "brw_cfg.h"
  26 #include "brw_fs_builder.h"
  27
  28 using namespace brw;
  29
  30 bool
  31 fs_visitor::lower_d2x()
  32 {
  33    bool progress = false;
  34
  35    foreach_block_and_inst_safe(block, fs_inst, inst, cfg) {
  36       if (inst->opcode != BRW_OPCODE_MOV)
  37          continue;
  38
  39       if (inst->dst.type != BRW_REGISTER_TYPE_F &&
  40           inst->dst.type != BRW_REGISTER_TYPE_D &&
  41           inst->dst.type != BRW_REGISTER_TYPE_UD)
  42          continue;
  43
  44       if (inst->src[0].type != BRW_REGISTER_TYPE_DF)
  45          continue;
  46
  47       assert(inst->dst.file == VGRF);
  48       assert(inst->saturate == false);
  49       fs_reg dst = inst->dst;
  50
  51       const fs_builder ibld(this, block, inst);
  52
  53       /* From the Broadwell PRM, 3D Media GPGPU, "Double Precision Float to
  54        * Single Precision Float":
  55        *
  56        *    The upper Dword of every Qword will be written with undefined
  57        *    value when converting DF to F.
  58        *
  59        * So we need to allocate a temporary that's two registers, and then do
  60        * a strided MOV to get the lower DWord of every Qword that has the
  61        * result.
  62        */
  63       fs_reg temp = ibld.vgrf(inst->src[0].type, 1);
  64       fs_reg strided_temp = subscript(temp, inst->dst.type, 0);
  65       ibld.MOV(strided_temp, inst->src[0]);
  66       ibld.MOV(dst, strided_temp);
  67
  68       inst->remove(block);
  69       progress = true;
  70    }
  71
  72    if (progress)
  73       invalidate_live_intervals();
  74
  75    return progress;
  76 }