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nir/opt_uniform_atomics: don't optimize atomics twice

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Applications sometimes already do this optimization themselves.

fossil-db (Navi):
Totals from 51 (0.04% of 135946) affected shaders:
CodeSize: 507484 -> 501860 (-1.11%)
Instrs: 99635 -> 98471 (-1.17%)
Cycles: 2421944 -> 2414780 (-0.30%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6558>
This commit is contained in:
Rhys Perry
2020-09-01 17:39:35 +01:00
committed by Marge Bot
parent bc43650522
commit a7114f3f46
1 changed files with 76 additions and 0 deletions
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src/compiler/nir/nir_opt_uniform_atomics.c
+76
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@@ -82,6 +82,79 @@ parse_atomic_op(nir_intrinsic_op op, unsigned *offset_src, unsigned *data_src)
}
}
/* Returns a bitmask of invocation indices that are compared against a subgroup
* uniform value.
*/
static unsigned
match_invocation_comparison(nir_ssa_scalar scalar)
{
if (!nir_ssa_scalar_is_alu(scalar))
return 0;
if (nir_ssa_scalar_alu_op(scalar) == nir_op_iand) {
return match_invocation_comparison(nir_ssa_scalar_chase_alu_src(scalar, 0)) |
match_invocation_comparison(nir_ssa_scalar_chase_alu_src(scalar, 1));
} else if (nir_ssa_scalar_alu_op(scalar) == nir_op_ieq) {
unsigned dims = 0;
for (unsigned i = 0; i < 2; i++) {
nir_ssa_scalar src = nir_ssa_scalar_chase_alu_src(scalar, i);
if (src.def->parent_instr->type != nir_instr_type_intrinsic)
continue;
if (nir_ssa_scalar_chase_alu_src(scalar, !i).def->divergent)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(src.def->parent_instr);
if (intrin->intrinsic == nir_intrinsic_load_subgroup_invocation)
dims = 0x8;
else if (intrin->intrinsic == nir_intrinsic_load_local_invocation_index)
dims = 0x7;
else if (intrin->intrinsic == nir_intrinsic_load_local_invocation_id)
dims = 1 << src.comp;
else if (intrin->intrinsic == nir_intrinsic_load_global_invocation_index)
dims = 0x7;
else if (intrin->intrinsic == nir_intrinsic_load_global_invocation_id)
dims = 1 << src.comp;
}
return dims;
} else if (scalar.def->parent_instr->type == nir_instr_type_intrinsic) {
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(scalar.def->parent_instr);
if (intrin->intrinsic == nir_intrinsic_elect)
return 0x8;
return 0;
} else {
return 0;
}
}
/* Returns true if the intrinsic is already conditional so that at most one
* invocation in the subgroup does the atomic.
*/
static bool
is_atomic_already_optimized(nir_shader *shader, nir_intrinsic_instr *instr)
{
unsigned dims = 0;
for (nir_cf_node *cf = &instr->instr.block->cf_node; cf; cf = cf->parent) {
if (cf->type == nir_cf_node_if) {
nir_block *first_then = nir_if_first_then_block(nir_cf_node_as_if(cf));
nir_block *last_then = nir_if_last_then_block(nir_cf_node_as_if(cf));
bool within_then = instr->instr.block->index >= first_then->index;
within_then = within_then && instr->instr.block->index <= last_then->index;
if (!within_then)
continue;
nir_ssa_scalar cond = {nir_cf_node_as_if(cf)->condition.ssa, 0};
dims |= match_invocation_comparison(cond);
}
}
unsigned dims_needed = 0;
for (unsigned i = 0; i < 3; i++)
dims_needed |= (shader->info.cs.local_size[i] > 1) << i;
return (dims & dims_needed) == dims_needed || dims & 0x8;
}
static nir_ssa_def *
emit_scalar_intrinsic(nir_builder *b, nir_intrinsic_op op, unsigned bit_size)
{
@@ -228,6 +301,9 @@ opt_uniform_atomics(nir_function_impl *impl)
if (nir_src_is_divergent(intrin->src[offset_src]))
continue;
if (is_atomic_already_optimized(b.shader, intrin))
continue;
b.cursor = nir_before_instr(instr);
optimize_and_rewrite_atomic(&b, intrin);
progress = true;