[Mesa-dev] [PATCH 2/3] nir/algebraic: support for power-of-two optimizations
Rob Clark
robdclark at gmail.com
Tue May 10 18:57:03 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)").
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_ */
--
2.5.5
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