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 "nir_worklist.h"
  33 #include "util/u_dynarray.h"
  34
  35 #define NIR_SEARCH_MAX_VARIABLES 16
  36
  37 struct nir_builder;
  38
  39 typedef enum {
  40    nir_search_value_expression,
  41    nir_search_value_variable,
  42    nir_search_value_constant,
  43 } nir_search_value_type;
  44
  45 typedef struct {
  46    nir_search_value_type type;
  47
  48    /**
  49     * Bit size of the value. It is interpreted as follows:
  50     *
  51     * For a search expression:
  52     * - If bit_size > 0, then the value only matches an SSA value with the
  53     *   given bit size.
  54     * - If bit_size <= 0, then the value matches any size SSA value.
  55     *
  56     * For a replace expression:
  57     * - If bit_size > 0, then the value is constructed with the given bit size.
  58     * - If bit_size == 0, then the value is constructed with the same bit size
  59     *   as the search value.
  60     * - If bit_size < 0, then the value is constructed with the same bit size
  61     *   as variable (-bit_size - 1).
  62     */
  63    int bit_size;
  64 } nir_search_value;
  65
  66 typedef struct {
  67    nir_search_value value;
  68
  69    /** The variable index;  Must be less than NIR_SEARCH_MAX_VARIABLES */
  70    unsigned variable;
  71
  72    /** Indicates that the given variable must be a constant
  73     *
  74     * This is only allowed in search expressions and indicates that the
  75     * given variable is only allowed to match constant values.
  76     */
  77    bool is_constant;
  78
  79    /** Indicates that the given variable must have a certain type
  80     *
  81     * This is only allowed in search expressions and indicates that the
  82     * given variable is only allowed to match values that come from an ALU
  83     * instruction with the given output type.  A type of nir_type_void
  84     * means it can match any type.
  85     *
  86     * Note: A variable that is both constant and has a non-void type will
  87     * never match anything.
  88     */
  89    nir_alu_type type;
  90
  91    /** Optional condition fxn ptr
  92     *
  93     * This is only allowed in search expressions, and allows additional
  94     * constraints to be placed on the match.  Typically used for 'is_constant'
  95     * variables to require, for example, power-of-two in order for the search
  96     * to match.
  97     */
  98    bool (*cond)(struct hash_table *range_ht, nir_alu_instr *instr, unsigned src,
  99                 unsigned num_components, const uint8_t *swizzle);
 100
 101    /** Swizzle (for replace only) */
 102    uint8_t swizzle[NIR_MAX_VEC_COMPONENTS];
 103 } nir_search_variable;
 104
 105 typedef struct {
 106    nir_search_value value;
 107
 108    nir_alu_type type;
 109
 110    union {
 111       uint64_t u;
 112       int64_t i;
 113       double d;
 114    } data;
 115 } nir_search_constant;
 116
 117 enum nir_search_op {
 118    nir_search_op_i2f = nir_last_opcode + 1,
 119    nir_search_op_u2f,
 120    nir_search_op_f2f,
 121    nir_search_op_f2u,
 122    nir_search_op_f2i,
 123    nir_search_op_u2u,
 124    nir_search_op_i2i,
 125    nir_search_op_b2f,
 126    nir_search_op_b2i,
 127    nir_search_op_i2b,
 128    nir_search_op_f2b,
 129    nir_num_search_ops,
 130 };
 131
 132 uint16_t nir_search_op_for_nir_op(nir_op op);
 133
 134 typedef struct {
 135    nir_search_value value;
 136
 137    /* When set on a search expression, the expression will only match an SSA
 138     * value that does *not* have the exact bit set.  If unset, the exact bit
 139     * on the SSA value is ignored.
 140     */
 141    bool inexact;
 142
 143    /** In a replacement, requests that the instruction be marked exact. */
 144    bool exact;
 145
 146    /* Commutative expression index.  This is assigned by opt_algebraic.py when
 147     * search structures are constructed and is a unique (to this structure)
 148     * index within the commutative operation bitfield used for searching for
 149     * all combinations of expressions containing commutative operations.
 150     */
 151    int8_t comm_expr_idx;
 152
 153    /* Number of commutative expressions in this expression including this one
 154     * (if it is commutative).
 155     */
 156    uint8_t comm_exprs;
 157
 158    /* One of nir_op or nir_search_op */
 159    uint16_t opcode;
 160    const nir_search_value *srcs[4];
 161
 162    /** Optional condition fxn ptr
 163     *
 164     * This allows additional constraints on expression matching, it is
 165     * typically used to match an expressions uses such as the number of times
 166     * the expression is used, and whether its used by an if.
 167     */
 168    bool (*cond)(nir_alu_instr *instr);
 169 } nir_search_expression;
 170
 171 struct per_op_table {
 172    const uint16_t *filter;
 173    unsigned num_filtered_states;
 174    const uint16_t *table;
 175 };
 176
 177 struct transform {
 178    const nir_search_expression *search;
 179    const nir_search_value *replace;
 180    unsigned condition_offset;
 181 };
 182
 183 /* Note: these must match the start states created in
 184  * TreeAutomaton._build_table()
 185  */
 186
 187 /* WILDCARD_STATE = 0 is set by zeroing the state array */
 188 static const uint16_t CONST_STATE = 1;
 189
 190 NIR_DEFINE_CAST(nir_search_value_as_variable, nir_search_value,
 191                 nir_search_variable, value,
 192                 type, nir_search_value_variable)
 193 NIR_DEFINE_CAST(nir_search_value_as_constant, nir_search_value,
 194                 nir_search_constant, value,
 195                 type, nir_search_value_constant)
 196 NIR_DEFINE_CAST(nir_search_value_as_expression, nir_search_value,
 197                 nir_search_expression, value,
 198                 type, nir_search_value_expression)
 199
 200 nir_ssa_def *
 201 nir_replace_instr(struct nir_builder *b, nir_alu_instr *instr,
 202                   struct hash_table *range_ht,
 203                   struct util_dynarray *states,
 204                   const struct per_op_table *pass_op_table,
 205                   const nir_search_expression *search,
 206                   const nir_search_value *replace,
 207                   nir_instr_worklist *algebraic_worklist);
 208 bool
 209 nir_algebraic_impl(nir_function_impl *impl,
 210                    const bool *condition_flags,
 211                    const struct transform **transforms,
 212                    const uint16_t *transform_counts,
 213                    const struct per_op_table *pass_op_table);
 214
 215 #endif /* _NIR_SEARCH_ */