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brw/copy: Copy prop -X into Y&1

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This commit prevents code quality regressions in the next
commit. Without this, some fragment shaders in Batman: Arkham Origins
have code like:

    shr(8)          g51<1>UW        g1.28<1,8,0>UB  0x76543210V
    ...
    and(8)          g52<1>UD        ~g51<8,8,1>UW   0x0001UW
    ...
    add(8)          g56<1>D         -g52<8,8,1>D    1D

transformed to

    shr(8)          g51<1>UW        g1.28<1,8,0>UB  0x76543210V
    ...
    and(8)          g52<1>UD        ~g51<8,8,1>UW   0x0001UW
    ...
    mov(8)          g56<1>D         -g52<8,8,1>D
    ...
    and(8)          g57<1>UD        ~g56<8,8,1>D    0x00000001UD

Propagating through the negation allows the added MOV to be deleted.

shader-db:

All Intel platforms had simlar results. (Lunar Lake shown)
total instructions in shared programs: 16968020 -> 16968019 (<.01%)
instructions in affected programs: 281 -> 280 (-0.36%)
helped: 1 / HURT: 0

total cycles in shared programs: 914598850 -> 914598832 (<.01%)
cycles in affected programs: 5398 -> 5380 (-0.33%)
helped: 1 / HURT: 0

A single Blender vertex shader was affected.

fossil-db:

Lunar Lake, Tiger Lake, Ice Lake, and Skylake had similar results. (Lunar Lake shown)
Totals:
Instrs: 209894650 -> 209894651 (+0.00%)
Cycle count: 30545958586 -> 30545952860 (-0.00%)

Totals from 2 (0.00% of 706657) affected shaders:
Instrs: 3582 -> 3583 (+0.03%)
Cycle count: 1875100 -> 1869374 (-0.31%)

Meteor Lake and DG2 had similar results. (Meteor Lake shown)
Totals:
Subgroup size: 9906400 -> 9906416 (+0.00%)

Totals from 2 (0.00% of 805770) affected shaders:
Subgroup size: 16 -> 32 (+100.00%)

Two compute shaders in Hogwarts Legacy were affected.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33931>
This commit is contained in:
Ian Romanick 2025-02-27 15:10:25 -08:00 • committed by Marge Bot
parent e82464e6e0
commit 3d23496fd9
1 changed files with 12 additions and 4 deletions
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16
src/intel/compiler/brw_opt_copy_propagation.cpp
View file

@ -862,7 +862,11 @@ try_copy_propagate(brw_shader &s, brw_inst *inst,
return false;
if (is_logic_op(inst->opcode)) {
return false;
/* For any value of X, X & 1 = -X & 1. In this case, source modifiers
* from entry will not be applied to inst (far below).
*/
if (inst->opcode != BRW_OPCODE_AND || !inst->src[1 - arg].is_one())
return false;
} else if (entry->dst.type != inst->src[arg].type &&
!inst->can_change_types()) {
/* Since semantics of source modifiers are type-dependent we need to
@ -921,7 +925,7 @@ try_copy_propagate(brw_shader &s, brw_inst *inst,
inst->src[arg] = byte_offset(inst->src[arg],
component * entry_stride * brw_type_size_bytes(entry->src.type) + suboffset);
if (has_source_modifiers) {
if (has_source_modifiers && !is_logic_op(inst->opcode)) {
if (entry->dst.type != inst->src[arg].type) {
/* We are propagating source modifiers from a MOV with a different
* type. If we got here, then we can just change the source and
@ -1599,7 +1603,11 @@ try_copy_propagate_def(brw_shader &s,
}
if (is_logic_op(inst->opcode)) {
return false;
/* For any value of X, X & 1 = -X & 1. In this case, source modifiers
* from entry will not be applied to inst (far below).
*/
if (inst->opcode != BRW_OPCODE_AND || !inst->src[1 - arg].is_one())
return false;
} else if (def->dst.type != inst->src[arg].type &&
!inst->can_change_types()) {
/* Since semantics of source modifiers are type-dependent we need to
@ -1790,7 +1798,7 @@ try_copy_propagate_def(brw_shader &s,
inst->exec_size = def->exec_size;
}
if (has_source_modifiers) {
if (has_source_modifiers && !is_logic_op(inst->opcode)) {
if (def->dst.type != inst->src[arg].type) {
/* We are propagating source modifiers from a MOV with a different
* type. If we got here, then we can just change the source and