[Mesa-dev] [PATCH] nir/algebraic: support for power-of-two optimizations
Rob Clark
robdclark at gmail.com
Tue May 24 21:41:48 UTC 2016
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)").
Signed-off-by: Rob Clark <robclark at freedesktop.org>
[for an earlier version:]
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
---
R-b's were on earlier version, before splitting out positive and
negative PoT condition functions and handling idiv in addition to
udiv.
The idiv rules do seem to work properly for case where 'a' is MIN_INT.
(Tested on both i965 and freedreno).
src/compiler/nir/nir.h | 3 ++
src/compiler/nir/nir_algebraic.py | 8 ++-
src/compiler/nir/nir_opt_algebraic.py | 15 ++++--
src/compiler/nir/nir_search.c | 3 ++
src/compiler/nir/nir_search.h | 10 ++++
src/compiler/nir/nir_search_helpers.h | 94 +++++++++++++++++++++++++++++++++++
6 files changed, 128 insertions(+), 5 deletions(-)
create mode 100644 src/compiler/nir/nir_search_helpers.h
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index dab0404..9b5d088 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -1652,6 +1652,9 @@ typedef struct nir_shader_compiler_options {
/* lower {slt,sge,seq,sne} to {flt,fge,feq,fne} + b2f: */
bool lower_scmp;
+ /** enables rules to lower idiv by power-of-two: */
+ bool lower_idiv;
+
/* Does the native fdot instruction replicate its result for four
* components? If so, then opt_algebraic_late will turn all fdotN
* instructions into fdot_replicatedN instructions.
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 f8db2b6..011263a 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -45,10 +45,11 @@ d = 'd'
# however, be used for backend-requested lowering operations as those need to
# happen regardless of precision.
#
-# Variable names are specified as "[#]name[@type]" where "#" inicates that
-# the given variable will only match constants and the type indicates that
+# Variable names are specified as "[#]name[@type][(cond)]" where "#" inicates
+# that the given variable will only match constants and the type indicates that
# the given variable will only match values from ALU instructions with the
-# given output type.
+# given output type, and (cond) specifies an additional condition function
+# (see nir_search_helpers.h).
#
# For constants, you have to be careful to make sure that it is the right
# type because python is unaware of the source and destination types of the
@@ -62,6 +63,14 @@ d = 'd'
# constructed value should have that bit-size.
optimizations = [
+
+ (('imul', a, '#b at 32(is_pos_power_of_two)'), ('ishl', a, ('find_lsb', b))),
+ (('imul', a, '#b at 32(is_neg_power_of_two)'), ('ineg', ('ishl', a, ('find_lsb', ('iabs', b))))),
+ (('udiv', a, '#b at 32(is_pos_power_of_two)'), ('ushr', a, ('find_lsb', b))),
+ (('idiv', a, '#b at 32(is_pos_power_of_two)'), ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', b))), 'options->lower_idiv'),
+ (('idiv', a, '#b at 32(is_neg_power_of_two)'), ('ineg', ('imul', ('isign', a), ('ushr', ('iabs', a), ('find_lsb', ('iabs', b))))), 'options->lower_idiv'),
+ (('umod', a, '#b(is_pos_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..5037944
--- /dev/null
+++ b/src/compiler/nir/nir_search_helpers.h
@@ -0,0 +1,94 @@
+/*
+ * 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_pos_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 (val->i32[swizzle[i]] < 0)
+ return false;
+ 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;
+}
+
+static inline bool
+is_neg_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 (val->i32[swizzle[i]] > 0)
+ return false;
+ if (!__is_power_of_two(abs(val->i32[swizzle[i]])))
+ return false;
+ break;
+ default:
+ return false;
+ }
+ }
+
+ return true;
+}
+
+#endif /* _NIR_SEARCH_ */
--
2.5.5
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