[Mesa-dev] [PATCH 2/3] nir/algebraic: support for power-of-two optimizations
Kenneth Graunke
kenneth at whitecape.org
Tue May 10 19:16:12 UTC 2016
On Tuesday, May 10, 2016 2:57:03 PM PDT Rob Clark wrote:
> From: Rob Clark <robclark at freedesktop.org>
>
> Some optimizations, like converting integer multiply/divide into left/
> right shifts, have additional constraints on the search expression.
> Like requiring that a variable is a constant power of two. Support
> these cases by allowing a fxn name to be appended to the search var
> expression (ie. "a#32(is_power_of_two)").
>
> TODO update doc/comment explaining search var syntax
> TODO the eagle-eyed viewer might have noticed that this could also
> replace the existing const syntax (ie. "#a"). Not sure if we should
> keep that.. we could make it syntactic sugar (ie '#' automatically sets
> the cond fxn ptr to 'is_const') or just get rid of it entirely? Maybe
> that is a follow-on clean-up patch?
>
> Signed-off-by: Rob Clark <robclark at freedesktop.org>
> ---
> src/compiler/nir/nir_algebraic.py | 8 +++--
> src/compiler/nir/nir_opt_algebraic.py | 5 +++
> src/compiler/nir/nir_search.c | 3 ++
> src/compiler/nir/nir_search.h | 10 ++++++
> src/compiler/nir/nir_search_helpers.h | 66 ++++++++++++++++++++++++++++++
+++++
> 5 files changed, 90 insertions(+), 2 deletions(-)
> create mode 100644 src/compiler/nir/nir_search_helpers.h
>
> diff --git a/src/compiler/nir/nir_algebraic.py b/src/compiler/nir/
nir_algebraic.py
> index 285f853..19ac6ee 100644
> --- a/src/compiler/nir/nir_algebraic.py
> +++ b/src/compiler/nir/nir_algebraic.py
> @@ -76,6 +76,7 @@ class Value(object):
> return Constant(val, name_base)
>
> __template = mako.template.Template("""
> +#include "compiler/nir/nir_search_helpers.h"
> static const ${val.c_type} ${val.name} = {
> { ${val.type_enum}, ${val.bit_size} },
> % if isinstance(val, Constant):
> @@ -84,6 +85,7 @@ static const ${val.c_type} ${val.name} = {
> ${val.index}, /* ${val.var_name} */
> ${'true' if val.is_constant else 'false'},
> ${val.type() or 'nir_type_invalid' },
> + ${val.cond if val.cond else 'NULL'},
> % elif isinstance(val, Expression):
> ${'true' if val.inexact else 'false'},
> nir_op_${val.opcode},
> @@ -113,7 +115,7 @@ static const ${val.c_type} ${val.name} = {
> Variable=Variable,
> Expression=Expression)
>
> -_constant_re = re.compile(r"(?P<value>[^@]+)(?:@(?P<bits>\d+))?")
> +_constant_re = re.compile(r"(?P<value>[^@\(]+)(?:@(?P<bits>\d+))?")
>
> class Constant(Value):
> def __init__(self, val, name):
> @@ -150,7 +152,8 @@ class Constant(Value):
> return "nir_type_float"
>
> _var_name_re = re.compile(r"(?P<const>#)?(?P<name>\w+)"
> - r"(?:@(?P<type>int|uint|bool|float)?(?P<bits>\d
+)?)?")
> + r"(?:@(?P<type>int|uint|bool|float)?(?P<bits>\d
+)?)?"
> + r"(?P<cond>\([^\)]+\))?")
>
> class Variable(Value):
> def __init__(self, val, name, varset):
> @@ -161,6 +164,7 @@ class Variable(Value):
>
> self.var_name = m.group('name')
> self.is_constant = m.group('const') is not None
> + self.cond = m.group('cond')
> self.required_type = m.group('type')
> self.bit_size = int(m.group('bits')) if m.group('bits') else 0
>
> diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/
nir_opt_algebraic.py
> index 0a95725..952a91a 100644
> --- a/src/compiler/nir/nir_opt_algebraic.py
> +++ b/src/compiler/nir/nir_opt_algebraic.py
> @@ -62,6 +62,11 @@ d = 'd'
> # constructed value should have that bit-size.
>
> optimizations = [
> +
> + (('imul', a, '#b at 32(is_power_of_two)'), ('ishl', a, ('find_lsb', b))),
> + (('udiv', a, '#b at 32(is_power_of_two)'), ('ushr', a, ('find_lsb', b))),
> + (('umod', a, '#b(is_power_of_two)'), ('iand', a, ('isub', b, 1))),
> +
> (('fneg', ('fneg', a)), a),
> (('ineg', ('ineg', a)), a),
> (('fabs', ('fabs', a)), ('fabs', a)),
> diff --git a/src/compiler/nir/nir_search.c b/src/compiler/nir/nir_search.c
> index 2c2fd92..b21fb2c 100644
> --- a/src/compiler/nir/nir_search.c
> +++ b/src/compiler/nir/nir_search.c
> @@ -127,6 +127,9 @@ match_value(const nir_search_value *value, nir_alu_instr
*instr, unsigned src,
> instr->src[src].src.ssa->parent_instr->type !=
nir_instr_type_load_const)
> return false;
>
> + if (var->cond && !var->cond(instr, src, num_components,
new_swizzle))
> + return false;
> +
> if (var->type != nir_type_invalid) {
> if (instr->src[src].src.ssa->parent_instr->type !=
nir_instr_type_alu)
> return false;
> diff --git a/src/compiler/nir/nir_search.h b/src/compiler/nir/nir_search.h
> index a500feb..f55d797 100644
> --- a/src/compiler/nir/nir_search.h
> +++ b/src/compiler/nir/nir_search.h
> @@ -68,6 +68,16 @@ typedef struct {
> * never match anything.
> */
> nir_alu_type type;
> +
> + /** Optional condition fxn ptr
> + *
> + * This is only allowed in search expressions, and allows additional
> + * constraints to be placed on the match. Typically used for
'is_constant'
> + * variables to require, for example, power-of-two in order for the
search
> + * to match.
> + */
> + bool (*cond)(nir_alu_instr *instr, unsigned src,
> + unsigned num_components, const uint8_t *swizzle);
> } nir_search_variable;
>
> typedef struct {
> diff --git a/src/compiler/nir/nir_search_helpers.h b/src/compiler/nir/
nir_search_helpers.h
> new file mode 100644
> index 0000000..8ed2ca0
> --- /dev/null
> +++ b/src/compiler/nir/nir_search_helpers.h
> @@ -0,0 +1,66 @@
> +/*
> + * Copyright © 2016 Red Hat
> + *
> + * 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:
> + * Rob Clark <robclark at freedesktop.org>
> + */
> +
> +#ifndef _NIR_SEARCH_HELPERS_
> +#define _NIR_SEARCH_HELPERS_
> +
> +#include "nir.h"
> +
> +static inline bool
> +__is_power_of_two(unsigned int x)
> +{
> + return ((x != 0) && !(x & (x - 1)));
> +}
> +
> +static inline bool
> +is_power_of_two(nir_alu_instr *instr, unsigned src, unsigned
num_components,
> + const uint8_t *swizzle)
> +{
> + nir_const_value *val = nir_src_as_const_value(instr->src[src].src);
> +
> + /* only constant src's: */
> + if (!val)
> + return false;
> +
> + for (unsigned i = 0; i < num_components; i++) {
> + switch (nir_op_infos[instr->op].input_types[src]) {
> + case nir_type_int:
> + if (!__is_power_of_two(val->i32[swizzle[i]]))
> + return false;
> + break;
> + case nir_type_uint:
> + if (!__is_power_of_two(val->u32[swizzle[i]]))
> + return false;
> + break;
> + default:
> + return false;
> + }
> + }
> +
> + return true;
> +}
> +
> +#endif /* _NIR_SEARCH_ */
>
FWIW, this is:
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
I'll defer to Jason's Ack/Nak though.
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