[Mesa-dev] [PATCH 01/11] intel/compiler: lower 16-bit integer extended math instructions
Iago Toral
itoral at igalia.com
Thu Apr 26 06:01:42 UTC 2018
On Wed, 2018-04-25 at 07:05 -0700, Jason Ekstrand wrote:
> Some of these comments may be duplicates of ones I made the first
> time through.
>
> On Wed, Apr 11, 2018 at 12:20 AM, Iago Toral Quiroga <itoral at igalia.c
> om> 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);
>
> For float16, we'll need f2f32.
Yes, I have that (in a separate pass for float16), I suppose merging
both makes more sense that having them be separate.
> Also, is_signed can be derived from nir_op_infos[op].input_types so
> it doesn't need to be passed in. If we want to make it fully
> general, we probably also want to only do the conversion if the
> source type is unsized.
Good point.
> > + }
> >
> > +
> >
> > + 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);
>
> Again, we can pull this from the destination type.
>
> > +
> >
> > + 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)
> >
> > +{
>
> As mentioned in previous discussions, we may want to have a control
> function such as
>
> unsigned (*lower_bit_size)(const nir_alu_instr *, void *)
>
> where the void * is something you pass in when you call the
> optimization pass. I'm usually not a huge fan of making a super-
> general thing before we need it. However, we already have two
> different drivers that need it for different things so let's just do
> it, make sure it works for all the use-cases, and get it right the
> first time.
Yes, I agree.
> > + 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;
> >
> > + /* Fallthrough */
> >
> > + case nir_op_udiv:
> >
> > + case nir_op_umod:
> >
> > + case nir_op_irem:
>
> irem is sgned.
Oops, right.
> > + 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);
>
> Probably only want to call this if (progress)
Ok.
> > +
> >
> > + return progress;
> >
> > +}
> >
> > +
> >
> > +bool
> >
> > +brw_nir_lower_16bit_int_math(nir_shader *shader)
>
> If we want this to handle 8-bit things, maybe it needs a different
> name. :-)
Yes, and also if we want this to handle floats.
Iago
> > +{
> >
> > + 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
> >
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