gcc/config/i386/k6.md

   1 ;; AMD K6/K6-2 Scheduling
   2 ;; Copyright (C) 2002-2020 Free Software Foundation, Inc.
   3 ;;
   4 ;; This file is part of GCC.
   5 ;;
   6 ;; GCC is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 3, or (at your option)
   9 ;; any later version.
  10 ;;
  11 ;; GCC is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15 ;;
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GCC; see the file COPYING3.  If not see
  18 ;; <http://www.gnu.org/licenses/>.
  19 ;;
  20 ;; The K6 architecture is quite similar to PPro.  Important difference is
  21 ;; that there are only two decoders and they seems to be much slower than
  22 ;; any of the execution units.  So we have to pay much more attention to
  23 ;; proper scheduling for the decoders.
  24 ;; FIXME: We don't do that right now.  A good start would be to sort the
  25 ;;        instructions based on length.
  26 ;;
  27 ;; This description is based on data from the following documents:
  28 ;;
  29 ;;    "AMD-K6 Processor Data Sheet (Preliminary information)"
  30 ;;    Advanced Micro Devices, Inc., 1998.
  31 ;;
  32 ;;    "AMD-K6 Processor Code Optimization Application Note"
  33 ;;    Advanced Micro Devices, Inc., 2000.
  34 ;;
  35 ;; CPU execution units of the K6:
  36 ;;
  37 ;; store        describes the Store unit.  This unit is not modelled
  38 ;;              completely and it is only used to model lea operation.
  39 ;;              Otherwise it lies outside of any critical path.
  40 ;; load         describes the Load unit
  41 ;; alux         describes the Integer X unit
  42 ;; mm           describes the Multimedia unit, which shares a pipe
  43 ;;              with the Integer X unit.  This unit is used for MMX,
  44 ;;              which is not implemented for K6.
  45 ;; aluy         describes the Integer Y unit
  46 ;; fpu          describes the FPU unit
  47 ;; branch       describes the Branch unit
  48 ;;
  49 ;; The fp unit is not pipelined, and it can only do one operation per two
  50 ;; cycles, including fxcg.
  51 ;;
  52 ;; Generally this is a very poor description, but at least no worse than
  53 ;; the old description, and a lot easier to extend to something more
  54 ;; reasonable if anyone still cares enough about this architecture in 2004.
  55 ;;
  56 ;; ??? fxch isn't handled; not an issue until sched3 after reg-stack is real.
  57
  58 (define_automaton "k6_decoder,k6_load_unit,k6_store_unit,k6_integer_units,k6_fpu_unit,k6_branch_unit")
  59
  60 ;; The K6 instruction decoding begins before the on-chip instruction cache is
  61 ;; filled.  Depending on the length of the instruction, two simple instructions
  62 ;; can be decoded in two parallel short decoders, or one complex instruction can
  63 ;; be decoded in either the long or the vector decoder.  For all practical
  64 ;; purposes, the long and vector decoder can be modelled as one decoder.
  65 (define_cpu_unit "k6_decode_short0" "k6_decoder")
  66 (define_cpu_unit "k6_decode_short1" "k6_decoder")
  67 (define_cpu_unit "k6_decode_long" "k6_decoder")
  68 (exclusion_set "k6_decode_long" "k6_decode_short0,k6_decode_short1")
  69 (define_reservation "k6_decode_short" "k6_decode_short0|k6_decode_short1")
  70 (define_reservation "k6_decode_vector" "k6_decode_long")
  71
  72 (define_cpu_unit "k6_store" "k6_store_unit")
  73 (define_cpu_unit "k6_load" "k6_load_unit")
  74 (define_cpu_unit "k6_alux,k6_aluy" "k6_integer_units")
  75 (define_cpu_unit "k6_fpu" "k6_fpu_unit")
  76 (define_cpu_unit "k6_branch" "k6_branch_unit")
  77
  78 ;; Shift instructions and certain arithmetic are issued only on Integer X.
  79 (define_insn_reservation "k6_alux_only" 1
  80                          (and (eq_attr "cpu" "k6")
  81                               (and (eq_attr "type" "ishift,ishift1,rotate,rotate1,alu1,negnot")
  82                                    (eq_attr "memory" "none")))
  83                          "k6_decode_short,k6_alux")
  84
  85 (define_insn_reservation "k6_alux_only_load" 3
  86                          (and (eq_attr "cpu" "k6")
  87                                (and (eq_attr "type" "ishift,ishift1,rotate,rotate1,alu1,negnot")
  88                                     (eq_attr "memory" "load")))
  89                          "k6_decode_short,k6_load,k6_alux")
  90
  91 (define_insn_reservation "k6_alux_only_store" 3
  92                          (and (eq_attr "cpu" "k6")
  93                                (and (eq_attr "type" "ishift,ishift1,rotate,rotate1,alu1,negnot")
  94                                     (eq_attr "memory" "store,both,unknown")))
  95                          "k6_decode_long,k6_load,k6_alux,k6_store")
  96
  97 ;; Integer divide and multiply can only be issued on Integer X, too.
  98 (define_insn_reservation "k6_alu_imul" 2
  99                          (and (eq_attr "cpu" "k6")
 100                               (eq_attr "type" "imul"))
 101                          "k6_decode_vector,k6_alux*3")
 102
 103 (define_insn_reservation "k6_alu_imul_load" 4
 104                          (and (eq_attr "cpu" "k6")
 105                               (and (eq_attr "type" "imul")
 106                                    (eq_attr "memory" "load")))
 107                          "k6_decode_vector,k6_load,k6_alux*3")
 108
 109 (define_insn_reservation "k6_alu_imul_store" 4
 110                          (and (eq_attr "cpu" "k6")
 111                               (and (eq_attr "type" "imul")
 112                                    (eq_attr "memory" "store,both,unknown")))
 113                          "k6_decode_vector,k6_load,k6_alux*3,k6_store")
 114
 115 ;; ??? Guessed latencies based on the old pipeline description.
 116 (define_insn_reservation "k6_alu_idiv" 17
 117                          (and (eq_attr "cpu" "k6")
 118                               (and (eq_attr "type" "idiv")
 119                                    (eq_attr "memory" "none")))
 120                          "k6_decode_vector,k6_alux*17")
 121
 122 (define_insn_reservation "k6_alu_idiv_mem" 19
 123                          (and (eq_attr "cpu" "k6")
 124                               (and (eq_attr "type" "idiv")
 125                                    (eq_attr "memory" "!none")))
 126                          "k6_decode_vector,k6_load,k6_alux*17")
 127
 128 ;; Basic word and doubleword ALU ops can be issued on both Integer units.
 129 (define_insn_reservation "k6_alu" 1
 130                          (and (eq_attr "cpu" "k6")
 131                               (and (eq_attr "type" "alu,alu1,negnot,icmp,test,imovx,incdec,setcc")
 132                                    (eq_attr "memory" "none")))
 133                          "k6_decode_short,k6_alux|k6_aluy")
 134
 135 (define_insn_reservation "k6_alu_load" 3
 136                          (and (eq_attr "cpu" "k6")
 137                               (and (eq_attr "type" "alu,alu1,negnot,icmp,test,imovx,incdec,setcc")
 138                                    (eq_attr "memory" "load")))
 139                          "k6_decode_short,k6_load,k6_alux|k6_aluy")
 140
 141 (define_insn_reservation "k6_alu_store" 3
 142                          (and (eq_attr "cpu" "k6")
 143                               (and (eq_attr "type" "alu,alu1,negnot,icmp,test,imovx,incdec,setcc")
 144                                    (eq_attr "memory" "store,both,unknown")))
 145                          "k6_decode_long,k6_load,k6_alux|k6_aluy,k6_store")
 146
 147 ;; A "load immediate" operation does not require execution at all,
 148 ;; it is available immediately after decoding.  Special-case this.
 149 (define_insn_reservation "k6_alu_imov" 1
 150                          (and (eq_attr "cpu" "k6")
 151                               (and (eq_attr "type" "imov")
 152                                    (and (eq_attr "memory" "none")
 153                                         (match_operand 1 "nonimmediate_operand"))))
 154                          "k6_decode_short,k6_alux|k6_aluy")
 155
 156 (define_insn_reservation "k6_alu_imov_imm" 0
 157                          (and (eq_attr "cpu" "k6")
 158                               (and (eq_attr "type" "imov")
 159                                    (and (eq_attr "memory" "none")
 160                                         (match_operand 1 "immediate_operand"))))
 161                          "k6_decode_short")
 162
 163 (define_insn_reservation "k6_alu_imov_load" 2
 164                          (and (eq_attr "cpu" "k6")
 165                               (and (eq_attr "type" "imov")
 166                                    (eq_attr "memory" "load")))
 167                          "k6_decode_short,k6_load")
 168
 169 (define_insn_reservation "k6_alu_imov_store" 1
 170                          (and (eq_attr "cpu" "k6")
 171                               (and (eq_attr "type" "imov")
 172                                    (eq_attr "memory" "store")))
 173                          "k6_decode_short,k6_store")
 174
 175 (define_insn_reservation "k6_alu_imov_both" 2
 176                          (and (eq_attr "cpu" "k6")
 177                               (and (eq_attr "type" "imov")
 178                                    (eq_attr "memory" "both,unknown")))
 179                          "k6_decode_long,k6_load,k6_alux|k6_aluy")
 180
 181 ;; The branch unit.
 182 (define_insn_reservation "k6_branch_call" 1
 183                          (and (eq_attr "cpu" "k6")
 184                               (eq_attr "type" "call,callv"))
 185                          "k6_decode_vector,k6_branch")
 186
 187 (define_insn_reservation "k6_branch_branch" 1
 188                          (and (eq_attr "cpu" "k6")
 189                               (eq_attr "type" "ibr"))
 190                          "k6_decode_short,k6_branch")
 191
 192 ;; The load and units have two pipeline stages.  The load latency is
 193 ;; two cycles.
 194 (define_insn_reservation "k6_load_pop" 3
 195                          (and (eq_attr "cpu" "k6")
 196                               (ior (eq_attr "type" "pop")
 197                                    (eq_attr "memory" "load,both")))
 198                          "k6_decode_short,k6_load")
 199
 200 (define_insn_reservation "k6_load_leave" 5
 201                          (and (eq_attr "cpu" "k6")
 202                               (eq_attr "type" "leave"))
 203                          "k6_decode_long,k6_load,(k6_alux|k6_aluy)*2")
 204
 205 ;; ??? From the old pipeline description.  Egad!
 206 ;; ??? Apparently we take care of this reservation in adjust_cost.
 207 (define_insn_reservation "k6_load_str" 10
 208                          (and (eq_attr "cpu" "k6")
 209                               (and (eq_attr "type" "str")
 210                                    (eq_attr "memory" "load,both")))
 211                          "k6_decode_vector,k6_load*10")
 212
 213 ;; The store unit handles lea and push.  It is otherwise unmodelled.
 214 (define_insn_reservation "k6_store_lea" 2
 215                          (and (eq_attr "cpu" "k6")
 216                               (eq_attr "type" "lea"))
 217                          "k6_decode_short,k6_store,k6_alux|k6_aluy")
 218
 219 (define_insn_reservation "k6_store_push" 2
 220                          (and (eq_attr "cpu" "k6")
 221                               (ior (eq_attr "type" "push")
 222                                    (eq_attr "memory" "store,both")))
 223                          "k6_decode_short,k6_store")
 224
 225 (define_insn_reservation "k6_store_str" 10
 226                          (and (eq_attr "cpu" "k6")
 227                               (eq_attr "type" "str"))
 228                          "k6_store*10")
 229
 230 ;; Most FPU instructions have latency 2 and throughput 2.
 231 (define_insn_reservation "k6_fpu" 2
 232                          (and (eq_attr "cpu" "k6")
 233                               (and (eq_attr "type" "fop,fmov,fcmp,fistp")
 234                                    (eq_attr "memory" "none")))
 235                          "k6_decode_vector,k6_fpu*2")
 236
 237 (define_insn_reservation "k6_fpu_load" 6
 238                          (and (eq_attr "cpu" "k6")
 239                               (and (eq_attr "type" "fop,fmov,fcmp,fistp")
 240                                    (eq_attr "memory" "load,both")))
 241                          "k6_decode_short,k6_load,k6_fpu*2")
 242
 243 (define_insn_reservation "k6_fpu_store" 6
 244                          (and (eq_attr "cpu" "k6")
 245                               (and (eq_attr "type" "fop,fmov,fcmp,fistp")
 246                                    (eq_attr "memory" "store")))
 247                          "k6_decode_short,k6_store,k6_fpu*2")
 248
 249 (define_insn_reservation "k6_fpu_fmul" 2
 250                          (and (eq_attr "cpu" "k6")
 251                               (and (eq_attr "type" "fmul")
 252                                    (eq_attr "memory" "none")))
 253                          "k6_decode_short,k6_fpu*2")
 254
 255 (define_insn_reservation "k6_fpu_fmul_load" 2
 256                          (and (eq_attr "cpu" "k6")
 257                               (and (eq_attr "type" "fmul")
 258                                    (eq_attr "memory" "load,both")))
 259                          "k6_decode_short,k6_load,k6_fpu*2")
 260
 261 ;; ??? Guessed latencies from the old pipeline description.
 262 (define_insn_reservation "k6_fpu_expensive" 56
 263                          (and (eq_attr "cpu" "k6")
 264                               (eq_attr "type" "fdiv,fpspc"))
 265                          "k6_decode_short,k6_fpu*56")
 266