src/compiler/nir/nir_search.h

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Jason Ekstrand (jason@jlekstrand.net)
  25  *
  26  */
  27
  28 #ifndef _NIR_SEARCH_
  29 #define _NIR_SEARCH_
  30
  31 #include "nir.h"
  32 #include "util/u_dynarray.h"
  33
  34 #define NIR_SEARCH_MAX_VARIABLES 16
  35
  36 struct nir_builder;
  37
  38 typedef enum {
  39    nir_search_value_expression,
  40    nir_search_value_variable,
  41    nir_search_value_constant,
  42 } nir_search_value_type;
  43
  44 typedef struct {
  45    nir_search_value_type type;
  46
  47    /**
  48     * Bit size of the value. It is interpreted as follows:
  49     *
  50     * For a search expression:
  51     * - If bit_size > 0, then the value only matches an SSA value with the
  52     *   given bit size.
  53     * - If bit_size <= 0, then the value matches any size SSA value.
  54     *
  55     * For a replace expression:
  56     * - If bit_size > 0, then the value is constructed with the given bit size.
  57     * - If bit_size == 0, then the value is constructed with the same bit size
  58     *   as the search value.
  59     * - If bit_size < 0, then the value is constructed with the same bit size
  60     *   as variable (-bit_size - 1).
  61     */
  62    int bit_size;
  63 } nir_search_value;
  64
  65 typedef struct {
  66    nir_search_value value;
  67
  68    /** The variable index;  Must be less than NIR_SEARCH_MAX_VARIABLES */
  69    unsigned variable;
  70
  71    /** Indicates that the given variable must be a constant
  72     *
  73     * This is only allowed in search expressions and indicates that the
  74     * given variable is only allowed to match constant values.
  75     */
  76    bool is_constant;
  77
  78    /** Indicates that the given variable must have a certain type
  79     *
  80     * This is only allowed in search expressions and indicates that the
  81     * given variable is only allowed to match values that come from an ALU
  82     * instruction with the given output type.  A type of nir_type_void
  83     * means it can match any type.
  84     *
  85     * Note: A variable that is both constant and has a non-void type will
  86     * never match anything.
  87     */
  88    nir_alu_type type;
  89
  90    /** Optional condition fxn ptr
  91     *
  92     * This is only allowed in search expressions, and allows additional
  93     * constraints to be placed on the match.  Typically used for 'is_constant'
  94     * variables to require, for example, power-of-two in order for the search
  95     * to match.
  96     */
  97    bool (*cond)(struct hash_table *range_ht, nir_alu_instr *instr, unsigned src,
  98                 unsigned num_components, const uint8_t *swizzle);
  99
 100    /** Swizzle (for replace only) */
 101    uint8_t swizzle[NIR_MAX_VEC_COMPONENTS];
 102 } nir_search_variable;
 103
 104 typedef struct {
 105    nir_search_value value;
 106
 107    nir_alu_type type;
 108
 109    union {
 110       uint64_t u;
 111       int64_t i;
 112       double d;
 113    } data;
 114 } nir_search_constant;
 115
 116 enum nir_search_op {
 117    nir_search_op_i2f = nir_last_opcode + 1,
 118    nir_search_op_u2f,
 119    nir_search_op_f2f,
 120    nir_search_op_f2u,
 121    nir_search_op_f2i,
 122    nir_search_op_u2u,
 123    nir_search_op_i2i,
 124    nir_search_op_b2f,
 125    nir_search_op_b2i,
 126    nir_search_op_i2b,
 127    nir_search_op_f2b,
 128    nir_num_search_ops,
 129 };
 130
 131 uint16_t nir_search_op_for_nir_op(nir_op op);
 132
 133 typedef struct {
 134    nir_search_value value;
 135
 136    /* When set on a search expression, the expression will only match an SSA
 137     * value that does *not* have the exact bit set.  If unset, the exact bit
 138     * on the SSA value is ignored.
 139     */
 140    bool inexact;
 141
 142    /** In a replacement, requests that the instruction be marked exact. */
 143    bool exact;
 144
 145    /* Commutative expression index.  This is assigned by opt_algebraic.py when
 146     * search structures are constructed and is a unique (to this structure)
 147     * index within the commutative operation bitfield used for searching for
 148     * all combinations of expressions containing commutative operations.
 149     */
 150    int8_t comm_expr_idx;
 151
 152    /* Number of commutative expressions in this expression including this one
 153     * (if it is commutative).
 154     */
 155    uint8_t comm_exprs;
 156
 157    /* One of nir_op or nir_search_op */
 158    uint16_t opcode;
 159    const nir_search_value *srcs[4];
 160
 161    /** Optional condition fxn ptr
 162     *
 163     * This allows additional constraints on expression matching, it is
 164     * typically used to match an expressions uses such as the number of times
 165     * the expression is used, and whether its used by an if.
 166     */
 167    bool (*cond)(nir_alu_instr *instr);
 168 } nir_search_expression;
 169
 170 struct per_op_table {
 171    const uint16_t *filter;
 172    unsigned num_filtered_states;
 173    const uint16_t *table;
 174 };
 175
 176 struct transform {
 177    const nir_search_expression *search;
 178    const nir_search_value *replace;
 179    unsigned condition_offset;
 180 };
 181
 182 /* Note: these must match the start states created in
 183  * TreeAutomaton._build_table()
 184  */
 185
 186 /* WILDCARD_STATE = 0 is set by zeroing the state array */
 187 static const uint16_t CONST_STATE = 1;
 188
 189 NIR_DEFINE_CAST(nir_search_value_as_variable, nir_search_value,
 190                 nir_search_variable, value,
 191                 type, nir_search_value_variable)
 192 NIR_DEFINE_CAST(nir_search_value_as_constant, nir_search_value,
 193                 nir_search_constant, value,
 194                 type, nir_search_value_constant)
 195 NIR_DEFINE_CAST(nir_search_value_as_expression, nir_search_value,
 196                 nir_search_expression, value,
 197                 type, nir_search_value_expression)
 198
 199 nir_ssa_def *
 200 nir_replace_instr(struct nir_builder *b, nir_alu_instr *instr,
 201                   struct hash_table *range_ht,
 202                   struct util_dynarray *states,
 203                   const struct per_op_table *pass_op_table,
 204                   const nir_search_expression *search,
 205                   const nir_search_value *replace);
 206 bool
 207 nir_algebraic_impl(nir_function_impl *impl,
 208                    const bool *condition_flags,
 209                    const struct transform **transforms,
 210                    const uint16_t *transform_counts,
 211                    const struct per_op_table *pass_op_table);
 212
 213 #endif /* _NIR_SEARCH_ */