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
lower_d2x()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 }
77