fdo-mirrors/mesa
1
0
Fork 0
mirror of https://gitlab.freedesktop.org/mesa/mesa.git synced 2026-03-21 22:40:35 +01:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

brw/algebraic: Convert some NOT to MOV

Browse source 
On Xe platforms, many fragment shaders have patterns like:

    asr(8)          g21<2>W         g1.2<0,1,0>W    15D
    ...
    mov(8)          g11<1>UW        g21<16,8,2>UW
    ...
    not.nz.f0.0(8)  null<1>D        g11<8,8,1>W

Converting the NOT.NZ to MOV.Z enables copy propagation to eliminate the
original MOV. Then cmod propagation is able to eliminate the
NOT-converted-to-MOV.

It might be possible to cover this case by adding more opcodes to the
list NOT can propagate to. The next commit will show that just
converting to MOV is a better approach anyway.

v2: Fix a bad squash. Changes that were supposed to be in this commit
were accidentally in the next commit. Noticed by Ivan.

shader-db:

Meteor Lake, DG2, and Tiger Lake had similar results. (Meteor Lake shown)
total instructions in shared programs: 20069804 -> 20065167 (-0.02%)
instructions in affected programs: 592450 -> 587813 (-0.78%)
helped: 2300 / HURT: 0

total cycles in shared programs: 884534032 -> 884496201 (<.01%)
cycles in affected programs: 13064194 -> 13026363 (-0.29%)
helped: 1285 / HURT: 790

LOST:   18
GAINED: 15

fossil-db:

Meteor Lake, DG2, and Tiger Lake had similar results. (Meteor Lake shown)
Totals:
Instrs: 234506495 -> 234468664 (-0.02%)
Cycle count: 24444825202 -> 24445710703 (+0.00%); split: -0.01%, +0.01%
Max live registers: 42349793 -> 42349789 (-0.00%)
Max dispatch width: 7131344 -> 7131744 (+0.01%); split: +0.05%, -0.04%

Totals from 16673 (2.07% of 805781) affected shaders:
Instrs: 6497669 -> 6459838 (-0.58%)
Cycle count: 435877770 -> 436763271 (+0.20%); split: -0.54%, +0.74%
Max live registers: 1122972 -> 1122968 (-0.00%)
Max dispatch width: 151528 -> 151928 (+0.26%); split: +2.19%, -1.92%

No shader-db or fossil-db on any other Intel platforms.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34509>
This commit is contained in:
Ian Romanick 2024-11-08 08:46:13 -08:00 • committed by Marge Bot
parent 9ce869aef5
commit 08fe7988d7
1 changed files with 23 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

23
src/intel/compiler/brw_opt_algebraic.cpp
View file

@ -489,6 +489,29 @@ brw_opt_algebraic(brw_shader &s)
}
}
break;
case BRW_OPCODE_NOT:
/* not.nz null, g17
*
* becomes
*
* mov.z null, g17
*
* These are equivalent, but the latter is easier for cmod prop.
*/
if (inst->dst.is_null() &&
inst->conditional_mod != BRW_CONDITIONAL_NONE) {
assert(!inst->src[0].abs);
if (!inst->src[0].negate)
inst->conditional_mod = brw_negate_cmod(inst->conditional_mod);
inst->opcode = BRW_OPCODE_MOV;
inst->src[0].negate = false;
progress = true;
}
break;
case BRW_OPCODE_OR:
if (inst->src[0].equals(inst->src[1]) || inst->src[1].is_zero()) {
/* On Gfx8+, the OR instruction can have a source modifier that