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
  33 #define NIR_SEARCH_MAX_VARIABLES 16
  34
  35 struct nir_builder;
  36
  37 typedef enum {
  38    nir_search_value_expression,
  39    nir_search_value_variable,
  40    nir_search_value_constant,
  41 } nir_search_value_type;
  42
  43 typedef struct {
  44    nir_search_value_type type;
  45
  46    /**
  47     * Bit size of the value. It is interpreted as follows:
  48     *
  49     * For a search expression:
  50     * - If bit_size > 0, then the value only matches an SSA value with the
  51     *   given bit size.
  52     * - If bit_size <= 0, then the value matches any size SSA value.
  53     *
  54     * For a replace expression:
  55     * - If bit_size > 0, then the value is constructed with the given bit size.
  56     * - If bit_size == 0, then the value is constructed with the same bit size
  57     *   as the search value.
  58     * - If bit_size < 0, then the value is constructed with the same bit size
  59     *   as variable (-bit_size - 1).
  60     */
  61    int bit_size;
  62 } nir_search_value;
  63
  64 typedef struct {
  65    nir_search_value value;
  66
  67    /** The variable index;  Must be less than NIR_SEARCH_MAX_VARIABLES */
  68    unsigned variable;
  69
  70    /** Indicates that the given variable must be a constant
  71     *
  72     * This is only allowed in search expressions and indicates that the
  73     * given variable is only allowed to match constant values.
  74     */
  75    bool is_constant;
  76
  77    /** Indicates that the given variable must have a certain type
  78     *
  79     * This is only allowed in search expressions and indicates that the
  80     * given variable is only allowed to match values that come from an ALU
  81     * instruction with the given output type.  A type of nir_type_void
  82     * means it can match any type.
  83     *
  84     * Note: A variable that is both constant and has a non-void type will
  85     * never match anything.
  86     */
  87    nir_alu_type type;
  88
  89    /** Optional condition fxn ptr
  90     *
  91     * This is only allowed in search expressions, and allows additional
  92     * constraints to be placed on the match.  Typically used for 'is_constant'
  93     * variables to require, for example, power-of-two in order for the search
  94     * to match.
  95     */
  96    bool (*cond)(struct hash_table *range_ht, nir_alu_instr *instr, unsigned src,
  97                 unsigned num_components, const uint8_t *swizzle);
  98
  99    /** Swizzle (for replace only) */
 100    uint8_t swizzle[NIR_MAX_VEC_COMPONENTS];
 101 } nir_search_variable;
 102
 103 typedef struct {
 104    nir_search_value value;
 105
 106    nir_alu_type type;
 107
 108    union {
 109       uint64_t u;
 110       int64_t i;
 111       double d;
 112    } data;
 113 } nir_search_constant;
 114
 115 enum nir_search_op {
 116    nir_search_op_i2f = nir_last_opcode + 1,
 117    nir_search_op_u2f,
 118    nir_search_op_f2f,
 119    nir_search_op_f2u,
 120    nir_search_op_f2i,
 121    nir_search_op_u2u,
 122    nir_search_op_i2i,
 123    nir_search_op_b2f,
 124    nir_search_op_b2i,
 125    nir_search_op_i2b,
 126    nir_search_op_f2b,
 127    nir_num_search_ops,
 128 };
 129
 130 uint16_t nir_search_op_for_nir_op(nir_op op);
 131
 132 typedef struct {
 133    nir_search_value value;
 134
 135    /* When set on a search expression, the expression will only match an SSA
 136     * value that does *not* have the exact bit set.  If unset, the exact bit
 137     * on the SSA value is ignored.
 138     */
 139    bool inexact;
 140
 141    /* Commutative expression index.  This is assigned by opt_algebraic.py when
 142     * search structures are constructed and is a unique (to this structure)
 143     * index within the commutative operation bitfield used for searching for
 144     * all combinations of expressions containing commutative operations.
 145     */
 146    int8_t comm_expr_idx;
 147
 148    /* Number of commutative expressions in this expression including this one
 149     * (if it is commutative).
 150     */
 151    uint8_t comm_exprs;
 152
 153    /* One of nir_op or nir_search_op */
 154    uint16_t opcode;
 155    const nir_search_value *srcs[4];
 156
 157    /** Optional condition fxn ptr
 158     *
 159     * This allows additional constraints on expression matching, it is
 160     * typically used to match an expressions uses such as the number of times
 161     * the expression is used, and whether its used by an if.
 162     */
 163    bool (*cond)(nir_alu_instr *instr);
 164 } nir_search_expression;
 165
 166 struct per_op_table {
 167    const uint16_t *filter;
 168    unsigned num_filtered_states;
 169    const uint16_t *table;
 170 };
 171
 172 struct transform {
 173    const nir_search_expression *search;
 174    const nir_search_value *replace;
 175    unsigned condition_offset;
 176 };
 177
 178 /* Note: these must match the start states created in
 179  * TreeAutomaton._build_table()
 180  */
 181
 182 /* WILDCARD_STATE = 0 is set by zeroing the state array */
 183 static const uint16_t CONST_STATE = 1;
 184
 185 NIR_DEFINE_CAST(nir_search_value_as_variable, nir_search_value,
 186                 nir_search_variable, value,
 187                 type, nir_search_value_variable)
 188 NIR_DEFINE_CAST(nir_search_value_as_constant, nir_search_value,
 189                 nir_search_constant, value,
 190                 type, nir_search_value_constant)
 191 NIR_DEFINE_CAST(nir_search_value_as_expression, nir_search_value,
 192                 nir_search_expression, value,
 193                 type, nir_search_value_expression)
 194
 195 nir_ssa_def *
 196 nir_replace_instr(struct nir_builder *b, nir_alu_instr *instr,
 197                   struct hash_table *range_ht,
 198                   const nir_search_expression *search,
 199                   const nir_search_value *replace);
 200 bool
 201 nir_algebraic_impl(nir_function_impl *impl,
 202                    const bool *condition_flags,
 203                    const struct transform **transforms,
 204                    const uint16_t *transform_counts,
 205                    const struct per_op_table *pass_op_table);
 206
 207 #endif /* _NIR_SEARCH_ */