[Mesa-dev] [PATCH 110/133] nir: Add an expression matching framework
Jason Ekstrand
jason at jlekstrand.net
Tue Jan 6 14:21:27 PST 2015
On Mon, Jan 5, 2015 at 10:00 PM, Jason Ekstrand <jason at jlekstrand.net>
wrote:
>
>
> On Mon, Jan 5, 2015 at 9:12 PM, Connor Abbott <cwabbott0 at gmail.com> wrote:
>
>> Hi,
>>
>> Was it your intention to not support non-per-component things like dot
>> product at all? I've made a few inline comments about how to do it,
>> and it doesn't seem like it's that hard.
>>
>
> No, It was just never tested on them. All your comments seem valid
> enough. I'll try and incorperate them.
>
>
>>
>> On Tue, Dec 16, 2014 at 1:12 AM, Jason Ekstrand <jason at jlekstrand.net>
>> wrote:
>> >
>> > This framework provides a simple way to do simple search-and-replace
>> > operations on NIR code. The nir_search.h header provides four simple
>> data
>> > structures for representing expressions: nir_value and four subtypes:
>> > nir_variable, nir_constant, and nir_expression. An expression tree can
>>
>> Make these be the actual names (nir_search_value, nir_search_variable,
>> etc.)
>>
>
> Yeah, no problem.
>
>
>>
>> > then be represented by nesting these data structures as needed. The
>> > nir_replace_instr function takes an instruction, an expression, and a
>> > value; if the instruction matches the expression, it is replaced with a
>> new
>> > chain of instructions to generate the given replacement value. The
>> > framework keeps track of swizzles on sources and automatically generates
>> > the currect swizzles for the replacement value.
>> > ---
>> > src/glsl/Makefile.sources | 2 +
>> > src/glsl/nir/nir_search.c | 337
>> ++++++++++++++++++++++++++++++++++++++++++++++
>> > src/glsl/nir/nir_search.h | 80 +++++++++++
>> > 3 files changed, 419 insertions(+)
>> > create mode 100644 src/glsl/nir/nir_search.c
>> > create mode 100644 src/glsl/nir/nir_search.h
>> >
>> > diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
>> > index 12c1d83..201330d 100644
>> > --- a/src/glsl/Makefile.sources
>> > +++ b/src/glsl/Makefile.sources
>> > @@ -41,6 +41,8 @@ NIR_FILES = \
>> > $(GLSL_SRCDIR)/nir/nir_opt_peephole_select.c \
>> > $(GLSL_SRCDIR)/nir/nir_print.c \
>> > $(GLSL_SRCDIR)/nir/nir_remove_dead_variables.c \
>> > + $(GLSL_SRCDIR)/nir/nir_search.c \
>> > + $(GLSL_SRCDIR)/nir/nir_search.h \
>> > $(GLSL_SRCDIR)/nir/nir_split_var_copies.c \
>> > $(GLSL_SRCDIR)/nir/nir_to_ssa.c \
>> > $(GLSL_SRCDIR)/nir/nir_validate.c \
>> > diff --git a/src/glsl/nir/nir_search.c b/src/glsl/nir/nir_search.c
>> > new file mode 100644
>> > index 0000000..257a53b
>> > --- /dev/null
>> > +++ b/src/glsl/nir/nir_search.c
>> > @@ -0,0 +1,337 @@
>> > +/*
>> > + * Copyright © 2014 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.
>> > + *
>> > + * Authors:
>> > + * Jason Ekstrand (jason at jlekstrand.net)
>> > + *
>> > + */
>> > +
>> > +#include "nir_search.h"
>> > +
>> > +struct match_state {
>> > + unsigned variables_seen;
>> > + nir_alu_src variables[NIR_SEARCH_MAX_VARIABLES];
>> > +};
>> > +
>> > +static bool
>> > +is_commutative_binop(nir_op op)
>> > +{
>> > + switch (op) {
>> > + case nir_op_fadd:
>> > + case nir_op_iadd:
>> > + case nir_op_fmul:
>> > + case nir_op_imul:
>> > + case nir_op_imul_high:
>> > + case nir_op_umul_high:
>> > + case nir_op_feq:
>> > + case nir_op_fne:
>> > + case nir_op_ieq:
>> > + case nir_op_ine:
>> > + case nir_op_fand:
>> > + case nir_op_for:
>> > + case nir_op_fxor:
>> > + case nir_op_iand:
>> > + case nir_op_ior:
>> > + case nir_op_ixor:
>> > + case nir_op_fmin:
>> > + case nir_op_fmax:
>> > + case nir_op_imin:
>> > + case nir_op_imax:
>> > + case nir_op_umin:
>> > + case nir_op_umax:
>> > + return true;
>> > + default:
>> > + return false;
>> > + }
>> > +}
>> > +
>> > +static bool
>> > +match_expression(const nir_search_expression *expr, nir_alu_instr
>> *instr,
>> > + unsigned num_components, const uint8_t *swizzle,
>> > + struct match_state *state);
>> > +
>> > +static bool
>> > +match_value(const nir_search_value *value, nir_alu_instr *instr,
>> unsigned src,
>> > + unsigned num_components, const uint8_t *swizzle,
>> > + struct match_state *state)
>> > +{
>> > + uint8_t new_swizzle[4];
>> > +
>> > + for (int i = 0; i < num_components; ++i)
>> > + new_swizzle[i] = instr->src[src].swizzle[swizzle[i]];
>> > +
>> > + switch (value->type) {
>> > + case nir_search_value_expression:
>> > + if (!instr->src[src].src.is_ssa)
>> > + return false;
>> > +
>> > + if (instr->src[src].src.ssa->parent_instr->type !=
>> nir_instr_type_alu)
>> > + return false;
>> > +
>> > + return match_expression(nir_search_value_as_expression(value),
>> > +
>> nir_instr_as_alu(instr->src[src].src.ssa->parent_instr),
>> > + num_components, new_swizzle, state);
>> > +
>> > + case nir_search_value_variable: {
>> > + nir_search_variable *var = nir_search_value_as_variable(value);
>> > +
>> > + if (state->variables_seen & (1 << var->variable)) {
>> > + if (!nir_srcs_equal(state->variables[0].src,
>> instr->src[src].src))
>>
>> I think you meant state->variables[var->variable].src here.
>>
>
> Yes, I think you're right. Kind of curious that this worked...
>
>
>>
>> >
>> > + return false;
>> >
>> > +
>> > + assert(!instr->src[src].abs && !instr->src[src].negate);
>> > +
>> > + for (int i = 0; i < num_components; ++i) {
>> > + if (state->variables[var->variable].swizzle[i] !=
>> new_swizzle[i])
>> > + return false;
>> > + }
>> > +
>> > + return true;
>> > + } else {
>> > + state->variables_seen |= (1 << var->variable);
>> > + state->variables[var->variable].src = instr->src[src].src;
>> > + state->variables[var->variable].abs = false;
>> > + state->variables[var->variable].negate = false;
>> > +
>> > + for (int i = 0; i < 4; ++i) {
>> > + if (i < num_components)
>> > + state->variables[var->variable].swizzle[i] =
>> new_swizzle[i];
>> > + else
>> > + state->variables[var->variable].swizzle[i] = 0;
>> > + }
>> > +
>> > + return true;
>> > + }
>> > + }
>> > +
>> > + case nir_search_value_constant: {
>> > + nir_search_constant *const_val =
>> nir_search_value_as_constant(value);
>> > +
>> > + if (!instr->src[src].src.is_ssa)
>> > + return false;
>> > +
>> > + if (instr->src[src].src.ssa->parent_instr->type !=
>> nir_instr_type_load_const)
>> > + return false;
>> > +
>> > + nir_load_const_instr *load =
>> > +
>> nir_instr_as_load_const(instr->src[src].src.ssa->parent_instr);
>> > +
>> > + switch (nir_op_infos[instr->op].input_types[src]) {
>> > + case nir_type_float:
>> > + for (unsigned i = 0; i < num_components; ++i) {
>> > + if (load->value.f[new_swizzle[i]] != const_val->data.f)
>> > + return false;
>> > + }
>> > + return true;
>> > + case nir_type_int:
>> > + case nir_type_unsigned:
>> > + case nir_type_bool:
>> > + for (unsigned i = 0; i < num_components; ++i) {
>> > + if (load->value.i[new_swizzle[i]] != const_val->data.i)
>> > + return false;
>> > + }
>> > + return true;
>> > + default:
>> > + unreachable("Invalid alu source type");
>> > + }
>> > + }
>> > +
>> > + default:
>> > + unreachable("Invalid search value type");
>> > + }
>> > +}
>> > +
>> > +static bool
>> > +match_expression(const nir_search_expression *expr, nir_alu_instr
>> *instr,
>> > + unsigned num_components, const uint8_t *swizzle,
>> > + struct match_state *state)
>> > +{
>> > + if (instr->op != expr->opcode)
>> > + return false;
>> > +
>> > + assert(!instr->dest.saturate);
>> > + assert(nir_op_infos[instr->op].num_inputs > 0);
>>
>>
>> If the instruction has a sized destination, we ought to bail out if
>> the swizzle isn't the identity or num_components isn't equal to the
>> identity for those components. Alternately, we could assert that the
>> only instructions with non-per-component destinations are at the root,
>> since it doesn't seem like there are that many optimizations with a
>> non-per-component instruction like "dot" or "any" that's not at the
>> root of the tree.
>>
>
> Good point.
>
Yes, we do need to bail on a non-trivial swizzle. However, I think not
using all the components is probably fine. The validator will ensure that
it doesn't use more components and not using all of them shouldn't be a
problem.
>
>
>> > +
>> > + bool matched = true;
>> > + for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
>> > + if (!match_value(expr->srcs[i], instr, i, num_components,
>> > + swizzle, state)) {
>>
>>
>> I think we need to pass in the correct number of components if the
>> source isn't per-component, since if we don't any optimizations
>> involving dot products will be totally broken. Similarly, I think we
>> need to reset the swizzle to the identity here for non-per-component
>> inputs.
>>
>
> Right
>
>
>>
>> >
>> > + matched = false;
>> > + break;
>> > + }
>> > + }
>> > +
>> > + if (matched)
>> > + return true;
>> > +
>> > + if (is_commutative_binop(instr->op)) {
>> > + if (!match_value(expr->srcs[0], instr, 1, num_components,
>> > + swizzle, state))
>> > + return false;
>> > +
>> > + return match_value(expr->srcs[1], instr, 0, num_components,
>> > + swizzle, state);
>> > + } else {
>> > + return false;
>> > + }
>> > +}
>> > +
>> > +static nir_alu_src
>> > +construct_value(const nir_search_value *value, nir_alu_type type,
>> > + unsigned num_components, struct match_state *state,
>> > + nir_instr *instr, void *mem_ctx)
>> > +{
>> > + switch (value->type) {
>> > + case nir_search_value_expression: {
>> > + const nir_search_expression *expr =
>> nir_search_value_as_expression(value);
>> > +
>> > + nir_alu_instr *alu = nir_alu_instr_create(mem_ctx, expr->opcode);
>> > + alu->dest.dest.is_ssa = true;
>> > + nir_ssa_def_init(&alu->instr, &alu->dest.dest.ssa,
>> num_components, NULL);
>> > + alu->dest.write_mask = (1 << num_components) - 1;
>> > + alu->dest.saturate = false;
>> > +
>> > + for (unsigned i = 0; i < nir_op_infos[expr->opcode].num_inputs;
>> i++) {
>> > + alu->src[i] = construct_value(expr->srcs[i],
>> > +
>> nir_op_infos[alu->op].input_types[i],
>> > + num_components,
>> > + state, instr, mem_ctx);
>>
>> Similarly to my earlier comment, we need to set num_components
>> correctly here if the source is not per-component.
>>
>
> Yup
>
>
>>
>> > + }
>> > +
>> > + nir_instr_insert_before(instr, &alu->instr);
>> > +
>> > + nir_alu_src val = {
>> > + .src.is_ssa = true,
>> > + .src.ssa = &alu->dest.dest.ssa,
>> > + .negate = false,
>> > + .abs = false,
>> > + .swizzle = { 0, 0, 0, 0 }
>> > + };
>> > +
>> > + /* No swizzling, but we can't have a swizzle value higher than
>> > + * num_components or the validator will get cranky.
>> > + */
>> > + for (unsigned i = 0; i < num_components; ++i)
>> > + val.swizzle[i] = i;
>>
>>
>> The validator only checks swizzle values that are actually being used,
>> so we can just do
>>
>> .swizzle = {0, 1, 2, 3}
>>
>> here and it should be fine.
>>
>
> Yeah, that should be ok.
>
>
>>
>> >
>> > +
>> > + return val;
>> > + }
>> > +
>> > + case nir_search_value_variable: {
>> > + const nir_search_variable *var =
>> nir_search_value_as_variable(value);
>> > + assert(state->variables_seen & (1 << var->variable));
>> > +
>> > + nir_alu_src val = state->variables[var->variable];
>> > + val.src = nir_src_copy(val.src, mem_ctx);
>> > +
>> > + return val;
>> > + }
>> > +
>> > + case nir_search_value_constant: {
>> > + const nir_search_constant *c =
>> nir_search_value_as_constant(value);
>> > + nir_load_const_instr *load =
>> nir_load_const_instr_create(mem_ctx);
>> > + load->dest.is_ssa = true;
>> > + nir_ssa_def_init(&load->instr, &load->dest.ssa, 1, NULL);
>> > +
>> > + switch (type) {
>> > + case nir_type_float:
>> > + load->dest.ssa.name = ralloc_asprintf(mem_ctx, "%f",
>> c->data.f);
>> > + load->value.f[0] = c->data.f;
>> > + break;
>> > + case nir_type_int:
>> > + load->dest.ssa.name = ralloc_asprintf(mem_ctx, "%d",
>> c->data.i);
>> > + load->value.i[0] = c->data.i;
>> > + break;
>> > + case nir_type_unsigned:
>> > + case nir_type_bool:
>> > + load->value.u[0] = c->data.u;
>> > + break;
>> > + default:
>> > + unreachable("Invalid alu source type");
>> > + }
>> > +
>> > + nir_instr_insert_before(instr, &load->instr);
>> > +
>> > + nir_alu_src val = {
>> > + .src.is_ssa = true,
>> > + .src.ssa = &load->dest.ssa,
>> > + .negate = false,
>> > + .abs = false,
>> > + .swizzle = { 0, 0, 0, 0 } /* Splatted scalar */
>> > + };
>> > +
>> > + return val;
>> > + }
>> > +
>> > + default:
>> > + unreachable("Invalid search value type");
>> > + }
>> > +}
>> > +
>> > +nir_alu_instr *
>> > +nir_replace_instr(nir_alu_instr *instr, const nir_search_expression
>> *search,
>> > + const nir_search_value *replace, void *mem_ctx)
>> > +{
>> > + uint8_t swizzle[4] = { 0, 0, 0, 0 };
>> > +
>> > + for (unsigned i = 0; i < instr->dest.dest.ssa.num_components; ++i)
>> > + swizzle[i] = i;
>> > +
>> > + assert(instr->dest.dest.is_ssa);
>> > +
>> > + struct match_state state;
>> > + state.variables_seen = 0;
>> > +
>> > + if (!match_expression(search, instr,
>> instr->dest.dest.ssa.num_components,
>> > + swizzle, &state))
>> > + return NULL;
>> > +
>> > + /* Inserting a mov may be unnecessary. However, it's much easier to
>> > + * simply let copy propagation clean this up than to try to go
>> through
>> > + * and rewrite swizzles ourselves.
>> > + */
>> > + nir_alu_instr *mov = nir_alu_instr_create(mem_ctx, nir_op_imov);
>> > + mov->dest.write_mask = instr->dest.write_mask;
>> > + mov->dest.dest.is_ssa = true;
>> > + nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa,
>> > + instr->dest.dest.ssa.num_components, NULL);
>> > +
>> > + mov->src[0] = construct_value(replace,
>> nir_op_infos[instr->op].output_type,
>> > + instr->dest.dest.ssa.num_components,
>> &state,
>> > + &instr->instr, mem_ctx);
>> > + nir_instr_insert_before(&instr->instr, &mov->instr);
>> > +
>> > + nir_src replace_src = {
>> > + .is_ssa = true,
>> > + .ssa = &mov->dest.dest.ssa,
>> > + };
>> > +
>> > + nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, replace_src,
>> mem_ctx);
>> > +
>> > + /* We know this one has no more uses because we just rewrote them
>> all,
>> > + * so we can remove it. The rest of the matched expression,
>> however, we
>> > + * don't know so much about. We'll just let dead code clean them
>> up.
>> > + */
>> > + nir_instr_remove(&instr->instr);
>> > +
>> > + return mov;
>> > +}
>> > diff --git a/src/glsl/nir/nir_search.h b/src/glsl/nir/nir_search.h
>> > new file mode 100644
>> > index 0000000..8ec58b0
>> > --- /dev/null
>> > +++ b/src/glsl/nir/nir_search.h
>> > @@ -0,0 +1,80 @@
>> > +/*
>> > + * Copyright © 2014 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.
>> > + *
>> > + * Authors:
>> > + * Jason Ekstrand (jason at jlekstrand.net)
>> > + *
>> > + */
>> > +
>> > +#ifndef _NIR_SEARCH_
>> > +#define _NIR_SEARCH_
>> > +
>> > +#include "nir.h"
>> > +
>> > +#define NIR_SEARCH_MAX_VARIABLES 16
>> > +
>> > +typedef enum {
>> > + nir_search_value_expression,
>> > + nir_search_value_variable,
>> > + nir_search_value_constant,
>> > +} nir_search_value_type;
>> > +
>> > +typedef struct {
>> > + nir_search_value_type type;
>> > +} nir_search_value;
>> > +
>> > +typedef struct {
>> > + nir_search_value value;
>> > +
>> > + /** The variable index; Must be less than NIR_SEARCH_MAX_VARIABLES
>> */
>> > + unsigned variable;
>> > +} nir_search_variable;
>> > +
>> > +typedef struct {
>> > + nir_search_value value;
>> > +
>> > + union {
>> > + uint32_t u;
>> > + int32_t i;
>> > + float f;
>> > + } data;
>> > +} nir_search_constant;
>> > +
>> > +typedef struct {
>> > + nir_search_value value;
>> > +
>> > + nir_op opcode;
>> > + const nir_search_value *srcs[4];
>> > +} nir_search_expression;
>> > +
>> > +NIR_DEFINE_CAST(nir_search_value_as_variable, nir_search_value,
>> > + nir_search_variable, value)
>> > +NIR_DEFINE_CAST(nir_search_value_as_constant, nir_search_value,
>> > + nir_search_constant, value)
>> > +NIR_DEFINE_CAST(nir_search_value_as_expression, nir_search_value,
>> > + nir_search_expression, value)
>> > +
>> > +nir_alu_instr *
>> > +nir_replace_instr(nir_alu_instr *instr, const nir_search_expression
>> *search,
>> > + const nir_search_value *replace, void *mem_ctx);
>> > +
>> > +#endif /* _NIR_SEARCH_ */
>> > --
>> > 2.2.0
>> >
>> > _______________________________________________
>> > mesa-dev mailing list
>> > mesa-dev at lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>
>
>
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