[Mesa-dev] [PATCH 01/11] intel/compiler: lower 16-bit integer extended math instructions
Jason Ekstrand
jason at jlekstrand.net
Tue Apr 24 21:45:00 UTC 2018
On Tue, Apr 24, 2018 at 7:38 AM, Rob Clark <robdclark at gmail.com> wrote:
> side-note, not sure if it really effects what you are doing here, but
> karol ran into some cases, like 8bit signed imax, which needs to be
> "lowered" to 16b (or 32b) and converted back for hw that doesn't
> support smaller than 16b (or 32b). I think I have the same case with
> ir3, which also has 16b but no 8b, (but he is a bit further along cl
> cts than I am)..
>
> I think there will be more of this sort of thing coming for more
> instructions and for more than just 16b vs 32b. So not sure if
> writing rules for each in nir_opt_algebraic.py will be so fun..
>
Yeah, it may be that what we want is a generic "lower this to something
with more bits" pass. If this is a problem for the CL people, maybe we
just want some way to make it configurable and put it in core NIR. I don't
really have a huge preference. I'm just trying to make sure we explore the
solution space.
--Jason
BR,
> -R
>
> On Tue, Apr 24, 2018 at 9:56 AM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
> > It may be useful to just use nir_algebraic for this. We already do for
> trig
> > workarounds. It's more painful from a build-system perspective but, in
> > general, the fewer hand-rolled algebraic lowering passes we have, the
> > better.
> >
> > On Wed, Apr 11, 2018 at 12:20 AM, Iago Toral Quiroga <itoral at igalia.com>
> > wrote:
> >>
> >> The hardware doesn't support 16-bit integer types, so we need to
> implement
> >> these using 32-bit integer instructions and then convert the result back
> >> to 16-bit.
> >> ---
> >> src/intel/Makefile.sources | 1 +
> >> src/intel/compiler/brw_nir.c | 2 +
> >> src/intel/compiler/brw_nir.h | 2 +
> >> src/intel/compiler/brw_nir_lower_16bit_int_math.c | 108
> >> ++++++++++++++++++++++
> >> src/intel/compiler/meson.build | 1 +
> >> 5 files changed, 114 insertions(+)
> >> create mode 100644 src/intel/compiler/brw_nir_lower_16bit_int_math.c
> >>
> >> diff --git a/src/intel/Makefile.sources b/src/intel/Makefile.sources
> >> index 91c71a8dfaf..2cd76961ea4 100644
> >> --- a/src/intel/Makefile.sources
> >> +++ b/src/intel/Makefile.sources
> >> @@ -79,6 +79,7 @@ COMPILER_FILES = \
> >> compiler/brw_nir_analyze_boolean_resolves.c \
> >> compiler/brw_nir_analyze_ubo_ranges.c \
> >> compiler/brw_nir_attribute_workarounds.c \
> >> + compiler/brw_nir_lower_16bit_int_math.c \
> >> compiler/brw_nir_lower_cs_intrinsics.c \
> >> compiler/brw_nir_opt_peephole_ffma.c \
> >> compiler/brw_nir_tcs_workarounds.c \
> >> diff --git a/src/intel/compiler/brw_nir.c b/src/intel/compiler/brw_nir.c
> >> index 69ab162f888..2e5754076ed 100644
> >> --- a/src/intel/compiler/brw_nir.c
> >> +++ b/src/intel/compiler/brw_nir.c
> >> @@ -638,6 +638,8 @@ brw_preprocess_nir(const struct brw_compiler
> >> *compiler, nir_shader *nir)
> >> nir_lower_isign64 |
> >> nir_lower_divmod64);
> >>
> >> + brw_nir_lower_16bit_int_math(nir);
> >> +
> >> nir = brw_nir_optimize(nir, compiler, is_scalar);
> >>
> >> if (is_scalar) {
> >> diff --git a/src/intel/compiler/brw_nir.h b/src/intel/compiler/brw_nir.h
> >> index 03f52da08e5..6ba1a8bc654 100644
> >> --- a/src/intel/compiler/brw_nir.h
> >> +++ b/src/intel/compiler/brw_nir.h
> >> @@ -152,6 +152,8 @@ void brw_nir_analyze_ubo_ranges(const struct
> >> brw_compiler *compiler,
> >>
> >> bool brw_nir_opt_peephole_ffma(nir_shader *shader);
> >>
> >> +bool brw_nir_lower_16bit_int_math(nir_shader *shader);
> >> +
> >> nir_shader *brw_nir_optimize(nir_shader *nir,
> >> const struct brw_compiler *compiler,
> >> bool is_scalar);
> >> diff --git a/src/intel/compiler/brw_nir_lower_16bit_int_math.c
> >> b/src/intel/compiler/brw_nir_lower_16bit_int_math.c
> >> new file mode 100644
> >> index 00000000000..6876309a822
> >> --- /dev/null
> >> +++ b/src/intel/compiler/brw_nir_lower_16bit_int_math.c
> >> @@ -0,0 +1,108 @@
> >> +/*
> >> + * Copyright © 2018 Intel Corporation
> >> + *
> >> + * 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 "brw_nir.h"
> >> +#include "nir_builder.h"
> >> +
> >> +/**
> >> + * Intel hardware doesn't support 16-bit integer Math instructions so
> >> this
> >> + * pass implements them in 32-bit and then converts the result back to
> >> 16-bit.
> >> + */
> >> +static void
> >> +lower_math_instr(nir_builder *bld, nir_alu_instr *alu, bool is_signed)
> >> +{
> >> + const nir_op op = alu->op;
> >> +
> >> + bld->cursor = nir_before_instr(&alu->instr);
> >> +
> >> + nir_ssa_def *srcs_32[4] = { NULL, NULL, NULL, NULL };
> >> + const uint32_t num_inputs = nir_op_infos[op].num_inputs;
> >> + for (uint32_t i = 0; i < num_inputs; i++) {
> >> + nir_ssa_def *src = nir_ssa_for_alu_src(bld, alu, i);
> >> + srcs_32[i] = is_signed ? nir_i2i32(bld, src) : nir_u2u32(bld,
> src);
> >> + }
> >> +
> >> + nir_ssa_def *dst_32 =
> >> + nir_build_alu(bld, op, srcs_32[0], srcs_32[1], srcs_32[2],
> >> srcs_32[3]);
> >> +
> >> + nir_ssa_def *dst_16 =
> >> + is_signed ? nir_i2i16(bld, dst_32) : nir_u2u16(bld, dst_32);
> >> +
> >> + nir_ssa_def_rewrite_uses(&alu->dest.dest.ssa,
> >> nir_src_for_ssa(dst_16));
> >> +}
> >> +
> >> +static bool
> >> +lower_instr(nir_builder *bld, nir_alu_instr *alu)
> >> +{
> >> + assert(alu->dest.dest.is_ssa);
> >> + if (alu->dest.dest.ssa.bit_size != 16)
> >> + return false;
> >> +
> >> + bool is_signed = false;
> >> + switch (alu->op) {
> >> + case nir_op_idiv:
> >> + case nir_op_imod:
> >> + is_signed = true;
> >
> >
> > You can get is_signed from nit_op_infos
> >
> >>
> >> + /* Fallthrough */
> >> + case nir_op_udiv:
> >> + case nir_op_umod:
> >> + case nir_op_irem:
> >
> >
> > How is irem unsigned?
> >
> >>
> >> + lower_math_instr(bld, alu, is_signed);
> >> + return true;
> >> + default:
> >> + return false;
> >> + }
> >> +}
> >> +
> >> +static bool
> >> +lower_impl(nir_function_impl *impl)
> >> +{
> >> + nir_builder b;
> >> + nir_builder_init(&b, impl);
> >> + bool progress = false;
> >> +
> >> + nir_foreach_block(block, impl) {
> >> + nir_foreach_instr_safe(instr, block) {
> >> + if (instr->type == nir_instr_type_alu)
> >> + progress |= lower_instr(&b, nir_instr_as_alu(instr));
> >> + }
> >> + }
> >> +
> >> + nir_metadata_preserve(impl, nir_metadata_block_index |
> >> + nir_metadata_dominance);
> >> +
> >> + return progress;
> >> +}
> >> +
> >> +bool
> >> +brw_nir_lower_16bit_int_math(nir_shader *shader)
> >> +{
> >> + bool progress = false;
> >> +
> >> + nir_foreach_function(function, shader) {
> >> + if (function->impl)
> >> + progress |= lower_impl(function->impl);
> >> + }
> >> +
> >> + return progress;
> >> +}
> >> diff --git a/src/intel/compiler/meson.build
> >> b/src/intel/compiler/meson.build
> >> index 72b7a6796cb..d80fcd6e31b 100644
> >> --- a/src/intel/compiler/meson.build
> >> +++ b/src/intel/compiler/meson.build
> >> @@ -76,6 +76,7 @@ libintel_compiler_files = files(
> >> 'brw_nir_analyze_boolean_resolves.c',
> >> 'brw_nir_analyze_ubo_ranges.c',
> >> 'brw_nir_attribute_workarounds.c',
> >> + 'brw_nir_lower_16bit_int_math.c',
> >> 'brw_nir_lower_cs_intrinsics.c',
> >> 'brw_nir_opt_peephole_ffma.c',
> >> 'brw_nir_tcs_workarounds.c',
> >> --
> >> 2.14.1
> >>
> >> _______________________________________________
> >> mesa-dev mailing list
> >> mesa-dev at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
> >
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
>
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