[Mesa-dev] [PATCH 03/16] ac/nir: Add vote_ieq/vote_feq lowering pass.
Jason Ekstrand
jason at jlekstrand.net
Sat Mar 10 17:26:38 UTC 2018
On Wed, Mar 7, 2018 at 6:47 AM, Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
wrote:
> The old vote_eq implementation supported only booleans, but now
> we have to support arbitrary values, so use the read_first_invocation
> intrinsic + ballot.
>
> I took this as an opportunity to figure out how easy it was to do this
> in nir instead of in the nir_to_llvm pass, and it actually turned out
> pretty okay IMO. Only creating the pass is some extra code.
>
We have nir_lower_subgroups for exactly this sort of thing. You might as
well put it in common code in case anyone else wants it. Also, it means
you can drop the boiler-plate. :-) Just put it behind a flag
lower_vote_to_cmp or something.
> Reviewed-by: Dave Airlie <airlied at redhat.com>
> ---
> src/amd/Makefile.sources | 1 +
> src/amd/common/ac_lower_subgroups.c | 92 ++++++++++++++++++++++++++++++
> +++++++
> src/amd/common/ac_nir_to_llvm.c | 8 ++--
> src/amd/common/ac_nir_to_llvm.h | 2 +
> src/amd/common/meson.build | 1 +
> 5 files changed, 99 insertions(+), 5 deletions(-)
> create mode 100644 src/amd/common/ac_lower_subgroups.c
>
> diff --git a/src/amd/Makefile.sources b/src/amd/Makefile.sources
> index 10c4827e19..f57dd403c5 100644
> --- a/src/amd/Makefile.sources
> +++ b/src/amd/Makefile.sources
> @@ -44,6 +44,7 @@ AMD_COMPILER_FILES = \
> common/ac_llvm_helper.cpp \
> common/ac_llvm_util.c \
> common/ac_llvm_util.h \
> + common/ac_lower_subgroups.c \
> common/ac_shader_abi.h \
> common/ac_shader_info.c \
> common/ac_shader_info.h \
> diff --git a/src/amd/common/ac_lower_subgroups.c
> b/src/amd/common/ac_lower_subgroups.c
> new file mode 100644
> index 0000000000..d0782b481b
> --- /dev/null
> +++ b/src/amd/common/ac_lower_subgroups.c
> @@ -0,0 +1,92 @@
> +/*
> + * Copyright © 2018 Google Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> "Software"),
> + * to deal in the Software without restriction, including without
> limitation
> + * the rights to use, copy, modify, merge, publish, distribute,
> sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> next
> + * paragraph) shall be included in all copies or substantial portions of
> the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
> SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include "nir/nir.h"
> +#include "nir/nir_builder.h"
> +
> +#include "ac_nir_to_llvm.h"
> +
> +static nir_ssa_def *ac_lower_subgroups_intrin(nir_builder *b,
> nir_intrinsic_instr *intrin)
> +{
> + switch(intrin->intrinsic) {
> + case nir_intrinsic_vote_ieq:
> + case nir_intrinsic_vote_feq: {
> + nir_intrinsic_instr *rfi =
> + nir_intrinsic_instr_create(b->shader,
> nir_intrinsic_read_first_invocation);
> + nir_ssa_dest_init(&rfi->instr, &rfi->dest,
> + 1, intrin->src[0].ssa->bit_size, NULL);
> + nir_src_copy(&rfi->src[0], &intrin->src[0], rfi);
> + rfi->num_components = 1;
> +
> + nir_ssa_def *is_ne;
> + if (intrin->intrinsic == nir_intrinsic_vote_feq)
> + is_ne = nir_fne(b, &rfi->dest.ssa,
> intrin->src[0].ssa);
> + else
> + is_ne = nir_ine(b, &rfi->dest.ssa,
> intrin->src[0].ssa);
> +
> + nir_intrinsic_instr *ballot =
> + nir_intrinsic_instr_create(b->shader,
> nir_intrinsic_ballot);
> + nir_ssa_dest_init(&ballot->instr, &ballot->dest,
> + 1, 64, NULL);
> + ballot->src[0] = nir_src_for_ssa(is_ne);
> + ballot->num_components = 1;
> +
> + return nir_ieq(b, &ballot->dest.ssa, nir_imm_int64(b, 0));
> + }
> + default:
> + return NULL;
> + }
> +}
> +
> +bool ac_lower_subgroups(struct nir_shader *shader)
> +{
> + bool progress = false;
> +
> + nir_foreach_function(function, shader) {
> + if (!function->impl)
> + continue;
> +
> + nir_builder b;
> + nir_builder_init(&b, function->impl);
> +
> + nir_foreach_block(block, function->impl) {
> + nir_foreach_instr_safe(instr, block) {
> + if (instr->type !=
> nir_instr_type_intrinsic)
> + continue;
> +
> + nir_intrinsic_instr *intrin =
> nir_instr_as_intrinsic(instr);
> + b.cursor = nir_before_instr(instr);
> +
> + nir_ssa_def *lower =
> ac_lower_subgroups_intrin(&b, intrin);
> + if (!lower)
> + continue;
> +
> + nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
> nir_src_for_ssa(lower));
> + nir_instr_remove(instr);
> + progress = true;
> + }
> + }
> + }
> +
> + return progress;
> +}
> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_
> llvm.c
> index d2df2837c8..3bf1a4ba3c 100644
> --- a/src/amd/common/ac_nir_to_llvm.c
> +++ b/src/amd/common/ac_nir_to_llvm.c
> @@ -4563,11 +4563,6 @@ static void visit_intrinsic(struct ac_nir_context
> *ctx,
> result = LLVMBuildSExt(ctx->ac.builder, tmp, ctx->ac.i32,
> "");
> break;
> }
> - case nir_intrinsic_vote_eq: {
> - LLVMValueRef tmp = ac_build_vote_eq(&ctx->ac, get_src(ctx,
> instr->src[0]));
> - result = LLVMBuildSExt(ctx->ac.builder, tmp, ctx->ac.i32,
> "");
> - break;
> - }
> default:
> fprintf(stderr, "Unknown intrinsic: ");
> nir_print_instr(&instr->instr, stderr);
> @@ -6737,6 +6732,9 @@ void ac_nir_translate(struct ac_llvm_context *ac,
> struct ac_shader_abi *abi,
> struct ac_nir_context ctx = {};
> struct nir_function *func;
>
> + /* Last minute passes for both radv & radeonsi */
> + ac_lower_subgroups(nir);
> +
> ctx.ac = *ac;
> ctx.abi = abi;
>
> diff --git a/src/amd/common/ac_nir_to_llvm.h b/src/amd/common/ac_nir_to_
> llvm.h
> index eea393a9c2..306039aecf 100644
> --- a/src/amd/common/ac_nir_to_llvm.h
> +++ b/src/amd/common/ac_nir_to_llvm.h
> @@ -234,4 +234,6 @@ void ac_lower_indirect_derefs(struct nir_shader *nir,
> enum chip_class);
> void ac_nir_translate(struct ac_llvm_context *ac, struct ac_shader_abi
> *abi,
> struct nir_shader *nir);
>
> +bool ac_lower_subgroups(struct nir_shader *shader);
> +
> #endif /* AC_NIR_TO_LLVM_H */
> diff --git a/src/amd/common/meson.build b/src/amd/common/meson.build
> index 22c13b955f..6c5c2f45ac 100644
> --- a/src/amd/common/meson.build
> +++ b/src/amd/common/meson.build
> @@ -35,6 +35,7 @@ amd_common_files = files(
> 'ac_llvm_helper.cpp',
> 'ac_llvm_util.c',
> 'ac_llvm_util.h',
> + 'ac_lower_subgroups.c',
> 'ac_shader_abi.h',
> 'ac_shader_info.c',
> 'ac_shader_info.h',
> --
> 2.16.1
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20180310/3dd64ac0/attachment-0001.html>
More information about the mesa-dev
mailing list