[Mesa-dev] [PATCH 31/56] nir: Add new SPIR-V ballot ALU intrinsics and lowering
Jason Ekstrand
jason at jlekstrand.net
Wed Mar 7 14:35:19 UTC 2018
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>
---
src/compiler/nir/nir_intrinsics.h | 19 ++++++++++++
src/compiler/nir/nir_lower_subgroups.c | 57 ++++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/src/compiler/nir/nir_intrinsics.h b/src/compiler/nir/nir_intrinsics.h
index ede2927..b8a6735 100644
--- a/src/compiler/nir/nir_intrinsics.h
+++ b/src/compiler/nir/nir_intrinsics.h
@@ -125,6 +125,25 @@ INTRINSIC(vote_any, 1, ARR(1), true, 1, 0, 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIM
INTRINSIC(vote_all, 1, ARR(1), true, 1, 0, 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
INTRINSIC(vote_eq, 1, ARR(1), true, 1, 0, 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+/** Ballot ALU operations from SPIR-V.
+ *
+ * These operations work like their ALU counterparts except that the operate
+ * on a uvec4 which is treated as a 128bit integer. Also, they are, in
+ * general, free to ignore any bits which are above the subgroup size.
+ */
+INTRINSIC(ballot_bitfield_extract, 2, ARR(4, 1), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+INTRINSIC(ballot_bit_count_reduce, 1, ARR(4), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+INTRINSIC(ballot_bit_count_inclusive, 1, ARR(4), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+INTRINSIC(ballot_bit_count_exclusive, 1, ARR(4), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+INTRINSIC(ballot_find_lsb, 1, ARR(4), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+INTRINSIC(ballot_find_msb, 1, ARR(4), true, 1, 0,
+ 0, xx, xx, xx, NIR_INTRINSIC_CAN_ELIMINATE)
+
/**
* Basic Geometry Shader intrinsics.
*
diff --git a/src/compiler/nir/nir_lower_subgroups.c b/src/compiler/nir/nir_lower_subgroups.c
index a99ffe2..acc6ed9 100644
--- a/src/compiler/nir/nir_lower_subgroups.c
+++ b/src/compiler/nir/nir_lower_subgroups.c
@@ -28,6 +28,21 @@
* \file nir_opt_intrinsics.c
*/
+static nir_ssa_def *
+ballot_type_to_uint(nir_builder *b, nir_ssa_def *value, unsigned bit_size)
+{
+ /* We only use this on uvec4 types */
+ assert(value->num_components == 4 && value->bit_size == 32);
+
+ if (bit_size == 32) {
+ return nir_channel(b, value, 0);
+ } else {
+ assert(bit_size == 64);
+ return nir_pack_64_2x32_split(b, nir_channel(b, value, 0),
+ nir_channel(b, value, 1));
+ }
+}
+
/* Converts a uint32_t or uint64_t value to uint64_t or uvec4 */
static nir_ssa_def *
uint_to_ballot_type(nir_builder *b, nir_ssa_def *value,
@@ -187,6 +202,48 @@ lower_subgroups_intrin(nir_builder *b, nir_intrinsic_instr *intrin,
intrin->dest.ssa.bit_size);
}
+ case nir_intrinsic_ballot_bitfield_extract:
+ case nir_intrinsic_ballot_bit_count_reduce:
+ case nir_intrinsic_ballot_find_lsb:
+ case nir_intrinsic_ballot_find_msb: {
+ assert(intrin->src[0].is_ssa);
+ nir_ssa_def *int_val = ballot_type_to_uint(b, intrin->src[0].ssa,
+ options->ballot_bit_size);
+ switch (intrin->intrinsic) {
+ case nir_intrinsic_ballot_bitfield_extract:
+ assert(intrin->src[1].is_ssa);
+ return nir_i2b(b, nir_iand(b, nir_ushr(b, int_val,
+ intrin->src[1].ssa),
+ nir_imm_int(b, 1)));
+ case nir_intrinsic_ballot_bit_count_reduce:
+ return nir_bit_count(b, int_val);
+ case nir_intrinsic_ballot_find_lsb:
+ return nir_find_lsb(b, int_val);
+ case nir_intrinsic_ballot_find_msb:
+ return nir_ufind_msb(b, int_val);
+ default:
+ unreachable("you seriously can't tell this is unreachable?");
+ }
+ }
+
+ case nir_intrinsic_ballot_bit_count_exclusive:
+ case nir_intrinsic_ballot_bit_count_inclusive: {
+ nir_ssa_def *count = nir_load_subgroup_invocation(b);
+ nir_ssa_def *mask = nir_imm_intN_t(b, ~0ull, options->ballot_bit_size);
+ if (intrin->intrinsic == nir_intrinsic_ballot_bit_count_inclusive) {
+ const unsigned bits = options->ballot_bit_size;
+ mask = nir_ushr(b, mask, nir_isub(b, nir_imm_int(b, bits - 1), count));
+ } else {
+ mask = nir_inot(b, nir_ishl(b, mask, count));
+ }
+
+ assert(intrin->src[0].is_ssa);
+ nir_ssa_def *int_val = ballot_type_to_uint(b, intrin->src[0].ssa,
+ options->ballot_bit_size);
+
+ return nir_bit_count(b, nir_iand(b, int_val, mask));
+ }
+
default:
break;
}
--
2.5.0.400.gff86faf
More information about the mesa-dev
mailing list