gcc/config/i386/x86-tune-sched.c

   1 /* Scheduler hooks for IA-32 which implement CPU specific logic.
   2    Copyright (C) 1988-2017 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 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "backend.h"
  24 #include "rtl.h"
  25 #include "tree.h"
  26 #include "cfghooks.h"
  27 #include "tm_p.h"
  28 #include "insn-config.h"
  29 #include "insn-attr.h"
  30 #include "recog.h"
  31 #include "target.h"
  32
  33 /* Return the maximum number of instructions a cpu can issue.  */
  34
  35 int
  36 ix86_issue_rate (void)
  37 {
  38   switch (ix86_tune)
  39     {
  40     case PROCESSOR_PENTIUM:
  41     case PROCESSOR_LAKEMONT:
  42     case PROCESSOR_BONNELL:
  43     case PROCESSOR_SILVERMONT:
  44     case PROCESSOR_KNL:
  45     case PROCESSOR_KNM:
  46     case PROCESSOR_INTEL:
  47     case PROCESSOR_K6:
  48     case PROCESSOR_BTVER2:
  49     case PROCESSOR_PENTIUM4:
  50     case PROCESSOR_NOCONA:
  51       return 2;
  52
  53     case PROCESSOR_PENTIUMPRO:
  54     case PROCESSOR_ATHLON:
  55     case PROCESSOR_K8:
  56     case PROCESSOR_AMDFAM10:
  57     case PROCESSOR_BTVER1:
  58       return 3;
  59
  60     case PROCESSOR_BDVER1:
  61     case PROCESSOR_BDVER2:
  62     case PROCESSOR_BDVER3:
  63     case PROCESSOR_BDVER4:
  64     case PROCESSOR_ZNVER1:
  65     case PROCESSOR_CORE2:
  66     case PROCESSOR_NEHALEM:
  67     case PROCESSOR_SANDYBRIDGE:
  68     case PROCESSOR_HASWELL:
  69     case PROCESSOR_GENERIC:
  70       return 4;
  71
  72     default:
  73       return 1;
  74     }
  75 }
  76
  77 /* Return true iff USE_INSN has a memory address with operands set by
  78    SET_INSN.  */
  79
  80 bool
  81 ix86_agi_dependent (rtx_insn *set_insn, rtx_insn *use_insn)
  82 {
  83   int i;
  84   extract_insn_cached (use_insn);
  85   for (i = recog_data.n_operands - 1; i >= 0; --i)
  86     if (MEM_P (recog_data.operand[i]))
  87       {
  88         rtx addr = XEXP (recog_data.operand[i], 0);
  89         if (modified_in_p (addr, set_insn) != 0)
  90           {
  91             /* No AGI stall if SET_INSN is a push or pop and USE_INSN
  92                has SP based memory (unless index reg is modified in a pop).  */
  93             rtx set = single_set (set_insn);
  94             if (set
  95                 && (push_operand (SET_DEST (set), GET_MODE (SET_DEST (set)))
  96                     || pop_operand (SET_SRC (set), GET_MODE (SET_SRC (set)))))
  97               {
  98                 struct ix86_address parts;
  99                 if (ix86_decompose_address (addr, &parts)
 100                     && parts.base == stack_pointer_rtx
 101                     && (parts.index == NULL_RTX
 102                         || MEM_P (SET_DEST (set))
 103                         || !modified_in_p (parts.index, set_insn)))
 104                   return false;
 105               }
 106             return true;
 107           }
 108         return false;
 109       }
 110   return false;
 111 }
 112
 113 /* A subroutine of ix86_adjust_cost -- return TRUE iff INSN reads flags set
 114    by DEP_INSN and nothing set by DEP_INSN.  */
 115
 116 static bool
 117 ix86_flags_dependent (rtx_insn *insn, rtx_insn *dep_insn, enum attr_type insn_type)
 118 {
 119   rtx set, set2;
 120
 121   /* Simplify the test for uninteresting insns.  */
 122   if (insn_type != TYPE_SETCC
 123       && insn_type != TYPE_ICMOV
 124       && insn_type != TYPE_FCMOV
 125       && insn_type != TYPE_IBR)
 126     return false;
 127
 128   if ((set = single_set (dep_insn)) != 0)
 129     {
 130       set = SET_DEST (set);
 131       set2 = NULL_RTX;
 132     }
 133   else if (GET_CODE (PATTERN (dep_insn)) == PARALLEL
 134            && XVECLEN (PATTERN (dep_insn), 0) == 2
 135            && GET_CODE (XVECEXP (PATTERN (dep_insn), 0, 0)) == SET
 136            && GET_CODE (XVECEXP (PATTERN (dep_insn), 0, 1)) == SET)
 137     {
 138       set = SET_DEST (XVECEXP (PATTERN (dep_insn), 0, 0));
 139       set2 = SET_DEST (XVECEXP (PATTERN (dep_insn), 0, 0));
 140     }
 141   else
 142     return false;
 143
 144   if (!REG_P (set) || REGNO (set) != FLAGS_REG)
 145     return false;
 146
 147   /* This test is true if the dependent insn reads the flags but
 148      not any other potentially set register.  */
 149   if (!reg_overlap_mentioned_p (set, PATTERN (insn)))
 150     return false;
 151
 152   if (set2 && reg_overlap_mentioned_p (set2, PATTERN (insn)))
 153     return false;
 154
 155   return true;
 156 }
 157
 158 /* Helper function for exact_store_load_dependency.
 159    Return true if addr is found in insn.  */
 160 static bool
 161 exact_dependency_1 (rtx addr, rtx insn)
 162 {
 163   enum rtx_code code;
 164   const char *format_ptr;
 165   int i, j;
 166
 167   code = GET_CODE (insn);
 168   switch (code)
 169     {
 170     case MEM:
 171       if (rtx_equal_p (addr, insn))
 172         return true;
 173       break;
 174     case REG:
 175     CASE_CONST_ANY:
 176     case SYMBOL_REF:
 177     case CODE_LABEL:
 178     case PC:
 179     case CC0:
 180     case EXPR_LIST:
 181       return false;
 182     default:
 183       break;
 184     }
 185
 186   format_ptr = GET_RTX_FORMAT (code);
 187   for (i = 0; i < GET_RTX_LENGTH (code); i++)
 188     {
 189       switch (*format_ptr++)
 190         {
 191         case 'e':
 192           if (exact_dependency_1 (addr, XEXP (insn, i)))
 193             return true;
 194           break;
 195         case 'E':
 196           for (j = 0; j < XVECLEN (insn, i); j++)
 197             if (exact_dependency_1 (addr, XVECEXP (insn, i, j)))
 198               return true;
 199           break;
 200         }
 201     }
 202   return false;
 203 }
 204
 205 /* Return true if there exists exact dependency for store & load, i.e.
 206    the same memory address is used in them.  */
 207 static bool
 208 exact_store_load_dependency (rtx_insn *store, rtx_insn *load)
 209 {
 210   rtx set1, set2;
 211
 212   set1 = single_set (store);
 213   if (!set1)
 214     return false;
 215   if (!MEM_P (SET_DEST (set1)))
 216     return false;
 217   set2 = single_set (load);
 218   if (!set2)
 219     return false;
 220   if (exact_dependency_1 (SET_DEST (set1), SET_SRC (set2)))
 221     return true;
 222   return false;
 223 }
 224
 225
 226 /* This function corrects the value of COST (latency) based on the relationship
 227    between INSN and DEP_INSN through a dependence of type DEP_TYPE, and strength
 228    DW.  It should return the new value.
 229
 230    On x86 CPUs this is most commonly used to model the fact that valus of
 231    registers used to compute address of memory operand  needs to be ready
 232    earlier than values of registers used in the actual operation.  */
 233
 234 int
 235 ix86_adjust_cost (rtx_insn *insn, int dep_type, rtx_insn *dep_insn, int cost,
 236                   unsigned int)
 237 {
 238   enum attr_type insn_type, dep_insn_type;
 239   enum attr_memory memory;
 240   rtx set, set2;
 241   int dep_insn_code_number;
 242
 243   /* Anti and output dependencies have zero cost on all CPUs.  */
 244   if (dep_type != 0)
 245     return 0;
 246
 247   dep_insn_code_number = recog_memoized (dep_insn);
 248
 249   /* If we can't recognize the insns, we can't really do anything.  */
 250   if (dep_insn_code_number < 0 || recog_memoized (insn) < 0)
 251     return cost;
 252
 253   insn_type = get_attr_type (insn);
 254   dep_insn_type = get_attr_type (dep_insn);
 255
 256   switch (ix86_tune)
 257     {
 258     case PROCESSOR_PENTIUM:
 259     case PROCESSOR_LAKEMONT:
 260       /* Address Generation Interlock adds a cycle of latency.  */
 261       if (insn_type == TYPE_LEA)
 262         {
 263           rtx addr = PATTERN (insn);
 264
 265           if (GET_CODE (addr) == PARALLEL)
 266             addr = XVECEXP (addr, 0, 0);
 267
 268           gcc_assert (GET_CODE (addr) == SET);
 269
 270           addr = SET_SRC (addr);
 271           if (modified_in_p (addr, dep_insn))
 272             cost += 1;
 273         }
 274       else if (ix86_agi_dependent (dep_insn, insn))
 275         cost += 1;
 276
 277       /* ??? Compares pair with jump/setcc.  */
 278       if (ix86_flags_dependent (insn, dep_insn, insn_type))
 279         cost = 0;
 280
 281       /* Floating point stores require value to be ready one cycle earlier.  */
 282       if (insn_type == TYPE_FMOV
 283           && get_attr_memory (insn) == MEMORY_STORE
 284           && !ix86_agi_dependent (dep_insn, insn))
 285         cost += 1;
 286       break;
 287
 288     case PROCESSOR_PENTIUMPRO:
 289       /* INT->FP conversion is expensive.  */
 290       if (get_attr_fp_int_src (dep_insn))
 291         cost += 5;
 292
 293       /* There is one cycle extra latency between an FP op and a store.  */
 294       if (insn_type == TYPE_FMOV
 295           && (set = single_set (dep_insn)) != NULL_RTX
 296           && (set2 = single_set (insn)) != NULL_RTX
 297           && rtx_equal_p (SET_DEST (set), SET_SRC (set2))
 298           && MEM_P (SET_DEST (set2)))
 299         cost += 1;
 300
 301       memory = get_attr_memory (insn);
 302
 303       /* Show ability of reorder buffer to hide latency of load by executing
 304          in parallel with previous instruction in case
 305          previous instruction is not needed to compute the address.  */
 306       if ((memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 307           && !ix86_agi_dependent (dep_insn, insn))
 308         {
 309           /* Claim moves to take one cycle, as core can issue one load
 310              at time and the next load can start cycle later.  */
 311           if (dep_insn_type == TYPE_IMOV
 312               || dep_insn_type == TYPE_FMOV)
 313             cost = 1;
 314           else if (cost > 1)
 315             cost--;
 316         }
 317       break;
 318
 319     case PROCESSOR_K6:
 320      /* The esp dependency is resolved before
 321         the instruction is really finished.  */
 322       if ((insn_type == TYPE_PUSH || insn_type == TYPE_POP)
 323           && (dep_insn_type == TYPE_PUSH || dep_insn_type == TYPE_POP))
 324         return 1;
 325
 326       /* INT->FP conversion is expensive.  */
 327       if (get_attr_fp_int_src (dep_insn))
 328         cost += 5;
 329
 330       memory = get_attr_memory (insn);
 331
 332       /* Show ability of reorder buffer to hide latency of load by executing
 333          in parallel with previous instruction in case
 334          previous instruction is not needed to compute the address.  */
 335       if ((memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 336           && !ix86_agi_dependent (dep_insn, insn))
 337         {
 338           /* Claim moves to take one cycle, as core can issue one load
 339              at time and the next load can start cycle later.  */
 340           if (dep_insn_type == TYPE_IMOV
 341               || dep_insn_type == TYPE_FMOV)
 342             cost = 1;
 343           else if (cost > 2)
 344             cost -= 2;
 345           else
 346             cost = 1;
 347         }
 348       break;
 349
 350     case PROCESSOR_AMDFAM10:
 351     case PROCESSOR_BDVER1:
 352     case PROCESSOR_BDVER2:
 353     case PROCESSOR_BDVER3:
 354     case PROCESSOR_BDVER4:
 355     case PROCESSOR_BTVER1:
 356     case PROCESSOR_BTVER2:
 357       /* Stack engine allows to execute push&pop instructions in parall.  */
 358       if ((insn_type == TYPE_PUSH || insn_type == TYPE_POP)
 359           && (dep_insn_type == TYPE_PUSH || dep_insn_type == TYPE_POP))
 360         return 0;
 361       /* FALLTHRU */
 362
 363     case PROCESSOR_ATHLON:
 364     case PROCESSOR_K8:
 365       memory = get_attr_memory (insn);
 366
 367       /* Show ability of reorder buffer to hide latency of load by executing
 368          in parallel with previous instruction in case
 369          previous instruction is not needed to compute the address.  */
 370       if ((memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 371           && !ix86_agi_dependent (dep_insn, insn))
 372         {
 373           enum attr_unit unit = get_attr_unit (insn);
 374           int loadcost = 3;
 375
 376           /* Because of the difference between the length of integer and
 377              floating unit pipeline preparation stages, the memory operands
 378              for floating point are cheaper.
 379
 380              ??? For Athlon it the difference is most probably 2.  */
 381           if (unit == UNIT_INTEGER || unit == UNIT_UNKNOWN)
 382             loadcost = 3;
 383           else
 384             loadcost = TARGET_ATHLON ? 2 : 0;
 385
 386           if (cost >= loadcost)
 387             cost -= loadcost;
 388           else
 389             cost = 0;
 390         }
 391       break;
 392
 393     case PROCESSOR_ZNVER1:
 394       /* Stack engine allows to execute push&pop instructions in parall.  */
 395       if ((insn_type == TYPE_PUSH || insn_type == TYPE_POP)
 396           && (dep_insn_type == TYPE_PUSH || dep_insn_type == TYPE_POP))
 397         return 0;
 398
 399       memory = get_attr_memory (insn);
 400
 401       /* Show ability of reorder buffer to hide latency of load by executing
 402          in parallel with previous instruction in case
 403          previous instruction is not needed to compute the address.  */
 404       if ((memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 405           && !ix86_agi_dependent (dep_insn, insn))
 406         {
 407           enum attr_unit unit = get_attr_unit (insn);
 408           int loadcost;
 409
 410           if (unit == UNIT_INTEGER || unit == UNIT_UNKNOWN)
 411             loadcost = 4;
 412           else
 413             loadcost = 7;
 414
 415           if (cost >= loadcost)
 416             cost -= loadcost;
 417           else
 418             cost = 0;
 419         }
 420       break;
 421
 422     case PROCESSOR_CORE2:
 423     case PROCESSOR_NEHALEM:
 424     case PROCESSOR_SANDYBRIDGE:
 425     case PROCESSOR_HASWELL:
 426     case PROCESSOR_GENERIC:
 427       /* Stack engine allows to execute push&pop instructions in parall.  */
 428       if ((insn_type == TYPE_PUSH || insn_type == TYPE_POP)
 429           && (dep_insn_type == TYPE_PUSH || dep_insn_type == TYPE_POP))
 430         return 0;
 431
 432       memory = get_attr_memory (insn);
 433
 434       /* Show ability of reorder buffer to hide latency of load by executing
 435          in parallel with previous instruction in case
 436          previous instruction is not needed to compute the address.  */
 437       if ((memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 438           && !ix86_agi_dependent (dep_insn, insn))
 439         {
 440           if (cost >= 4)
 441             cost -= 4;
 442           else
 443             cost = 0;
 444         }
 445       break;
 446
 447     case PROCESSOR_SILVERMONT:
 448     case PROCESSOR_KNL:
 449     case PROCESSOR_KNM:
 450     case PROCESSOR_INTEL:
 451       if (!reload_completed)
 452         return cost;
 453
 454       /* Increase cost of integer loads.  */
 455       memory = get_attr_memory (dep_insn);
 456       if (memory == MEMORY_LOAD || memory == MEMORY_BOTH)
 457         {
 458           enum attr_unit unit = get_attr_unit (dep_insn);
 459           if (unit == UNIT_INTEGER && cost == 1)
 460             {
 461               if (memory == MEMORY_LOAD)
 462                 cost = 3;
 463               else
 464                 {
 465                   /* Increase cost of ld/st for short int types only
 466                      because of store forwarding issue.  */
 467                   rtx set = single_set (dep_insn);
 468                   if (set && (GET_MODE (SET_DEST (set)) == QImode
 469                               || GET_MODE (SET_DEST (set)) == HImode))
 470                     {
 471                       /* Increase cost of store/load insn if exact
 472                          dependence exists and it is load insn.  */
 473                       enum attr_memory insn_memory = get_attr_memory (insn);
 474                       if (insn_memory == MEMORY_LOAD
 475                           && exact_store_load_dependency (dep_insn, insn))
 476                         cost = 3;
 477                     }
 478                 }
 479             }
 480         }
 481
 482     default:
 483       break;
 484     }
 485
 486   return cost;
 487 }
 488
 489 /* How many alternative schedules to try.  This should be as wide as the
 490    scheduling freedom in the DFA, but no wider.  Making this value too
 491    large results extra work for the scheduler.  */
 492
 493 int
 494 ia32_multipass_dfa_lookahead (void)
 495 {
 496   /* Generally, we want haifa-sched:max_issue() to look ahead as far
 497      as many instructions can be executed on a cycle, i.e.,
 498      issue_rate.  */
 499   if (reload_completed)
 500     return ix86_issue_rate ();
 501   /* Don't use lookahead for pre-reload schedule to save compile time.  */
 502   return 0;
 503 }
 504
 505 /* Return true if target platform supports macro-fusion.  */
 506
 507 bool
 508 ix86_macro_fusion_p ()
 509 {
 510   return TARGET_FUSE_CMP_AND_BRANCH;
 511 }
 512
 513 /* Check whether current microarchitecture support macro fusion
 514    for insn pair "CONDGEN + CONDJMP". Refer to
 515    "Intel Architectures Optimization Reference Manual". */
 516
 517 bool
 518 ix86_macro_fusion_pair_p (rtx_insn *condgen, rtx_insn *condjmp)
 519 {
 520   rtx src, dest;
 521   enum rtx_code ccode;
 522   rtx compare_set = NULL_RTX, test_if, cond;
 523   rtx alu_set = NULL_RTX, addr = NULL_RTX;
 524
 525   if (!any_condjump_p (condjmp))
 526     return false;
 527
 528   unsigned int condreg1, condreg2;
 529   rtx cc_reg_1;
 530   targetm.fixed_condition_code_regs (&condreg1, &condreg2);
 531   cc_reg_1 = gen_rtx_REG (CCmode, condreg1);
 532   if (!reg_referenced_p (cc_reg_1, PATTERN (condjmp))
 533       || !condgen
 534       || !modified_in_p (cc_reg_1, condgen))
 535     return false;
 536
 537   if (get_attr_type (condgen) != TYPE_TEST
 538       && get_attr_type (condgen) != TYPE_ICMP
 539       && get_attr_type (condgen) != TYPE_INCDEC
 540       && get_attr_type (condgen) != TYPE_ALU)
 541     return false;
 542
 543   compare_set = single_set (condgen);
 544   if (compare_set == NULL_RTX
 545       && !TARGET_FUSE_ALU_AND_BRANCH)
 546     return false;
 547
 548   if (compare_set == NULL_RTX)
 549     {
 550       int i;
 551       rtx pat = PATTERN (condgen);
 552       for (i = 0; i < XVECLEN (pat, 0); i++)
 553         if (GET_CODE (XVECEXP (pat, 0, i)) == SET)
 554           {
 555             rtx set_src = SET_SRC (XVECEXP (pat, 0, i));
 556             if (GET_CODE (set_src) == COMPARE)
 557               compare_set = XVECEXP (pat, 0, i);
 558             else
 559               alu_set = XVECEXP (pat, 0, i);
 560           }
 561     }
 562   if (compare_set == NULL_RTX)
 563     return false;
 564   src = SET_SRC (compare_set);
 565   if (GET_CODE (src) != COMPARE)
 566     return false;
 567
 568   /* Macro-fusion for cmp/test MEM-IMM + conditional jmp is not
 569      supported.  */
 570   if ((MEM_P (XEXP (src, 0))
 571        && CONST_INT_P (XEXP (src, 1)))
 572       || (MEM_P (XEXP (src, 1))
 573           && CONST_INT_P (XEXP (src, 0))))
 574     return false;
 575
 576   /* No fusion for RIP-relative address.  */
 577   if (MEM_P (XEXP (src, 0)))
 578     addr = XEXP (XEXP (src, 0), 0);
 579   else if (MEM_P (XEXP (src, 1)))
 580     addr = XEXP (XEXP (src, 1), 0);
 581
 582   if (addr) {
 583     ix86_address parts;
 584     int ok = ix86_decompose_address (addr, &parts);
 585     gcc_assert (ok);
 586
 587     if (ix86_rip_relative_addr_p (&parts))
 588       return false;
 589   }
 590
 591   test_if = SET_SRC (pc_set (condjmp));
 592   cond = XEXP (test_if, 0);
 593   ccode = GET_CODE (cond);
 594   /* Check whether conditional jump use Sign or Overflow Flags.  */
 595   if (!TARGET_FUSE_CMP_AND_BRANCH_SOFLAGS
 596       && (ccode == GE
 597           || ccode == GT
 598           || ccode == LE
 599           || ccode == LT))
 600     return false;
 601
 602   /* Return true for TYPE_TEST and TYPE_ICMP.  */
 603   if (get_attr_type (condgen) == TYPE_TEST
 604       || get_attr_type (condgen) == TYPE_ICMP)
 605     return true;
 606
 607   /* The following is the case that macro-fusion for alu + jmp.  */
 608   if (!TARGET_FUSE_ALU_AND_BRANCH || !alu_set)
 609     return false;
 610
 611   /* No fusion for alu op with memory destination operand.  */
 612   dest = SET_DEST (alu_set);
 613   if (MEM_P (dest))
 614     return false;
 615
 616   /* Macro-fusion for inc/dec + unsigned conditional jump is not
 617      supported.  */
 618   if (get_attr_type (condgen) == TYPE_INCDEC
 619       && (ccode == GEU
 620           || ccode == GTU
 621           || ccode == LEU
 622           || ccode == LTU))
 623     return false;
 624
 625   return true;
 626 }
 627