gcc/config/i386/x86-tune.def

   1 /* Definitions of x86 tunable features.
   2    Copyright (C) 2013-2019 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 and
  17 a copy of the GCC Runtime Library Exception along with this program;
  18 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* Tuning for a given CPU XXXX consists of:
  22     - adding new CPU into:
  23         - adding PROCESSOR_XXX to processor_type (in i386.h)
  24         - possibly adding XXX into CPU attribute in i386.md
  25         - adding XXX to processor_alias_table (in i386.c)
  26     - introducing ix86_XXX_cost in i386.c
  27         - Stringop generation table can be build based on test_stringop
  28         - script (once rest of tuning is complete)
  29     - designing a scheduler model in
  30         - XXXX.md file
  31         - Updating ix86_issue_rate and ix86_adjust_cost in i386.md
  32         - possibly updating ia32_multipass_dfa_lookahead, ix86_sched_reorder
  33           and ix86_sched_init_global if those tricks are needed.
  34     - Tunning the flags bellow. Those are split into sections and each
  35       section is very roughly ordered by importance.  */
  36
  37 /*****************************************************************************/
  38 /* Scheduling flags.                                                         */
  39 /*****************************************************************************/
  40
  41 /* X86_TUNE_SCHEDULE: Enable scheduling.  */
  42 DEF_TUNE (X86_TUNE_SCHEDULE, "schedule",
  43           m_PENT | m_LAKEMONT | m_PPRO | m_CORE_ALL | m_BONNELL | m_SILVERMONT
  44           | m_INTEL | m_KNL | m_KNM | m_K6_GEODE | m_AMD_MULTIPLE | m_GOLDMONT
  45           | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC)
  46
  47 /* X86_TUNE_PARTIAL_REG_DEPENDENCY: Enable more register renaming
  48    on modern chips.  Preffer stores affecting whole integer register
  49    over partial stores.  For example preffer MOVZBL or MOVQ to load 8bit
  50    value over movb.  */
  51 DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency",
  52           m_P4_NOCONA | m_CORE2 | m_NEHALEM  | m_SANDYBRIDGE | m_CORE_AVX2
  53           | m_BONNELL | m_SILVERMONT | m_GOLDMONT | m_GOLDMONT_PLUS | m_INTEL
  54           | m_KNL | m_KNM | m_AMD_MULTIPLE | m_TREMONT
  55           | m_GENERIC)
  56
  57 /* X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY: This knob promotes all store
  58    destinations to be 128bit to allow register renaming on 128bit SSE units,
  59    but usually results in one extra microop on 64bit SSE units.
  60    Experimental results shows that disabling this option on P4 brings over 20%
  61    SPECfp regression, while enabling it on K8 brings roughly 2.4% regression
  62    that can be partly masked by careful scheduling of moves.  */
  63 DEF_TUNE (X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY, "sse_partial_reg_dependency",
  64           m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_AMDFAM10
  65           | m_BDVER | m_ZNVER | m_GENERIC)
  66
  67 /* X86_TUNE_SSE_SPLIT_REGS: Set for machines where the type and dependencies
  68    are resolved on SSE register parts instead of whole registers, so we may
  69    maintain just lower part of scalar values in proper format leaving the
  70    upper part undefined.  */
  71 DEF_TUNE (X86_TUNE_SSE_SPLIT_REGS, "sse_split_regs", m_ATHLON_K8)
  72
  73 /* X86_TUNE_PARTIAL_FLAG_REG_STALL: this flag disables use of of flags
  74    set by instructions affecting just some flags (in particular shifts).
  75    This is because Core2 resolves dependencies on whole flags register
  76    and such sequences introduce false dependency on previous instruction
  77    setting full flags.
  78
  79    The flags does not affect generation of INC and DEC that is controlled
  80    by X86_TUNE_USE_INCDEC.  */
  81
  82 DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL, "partial_flag_reg_stall",
  83           m_CORE2)
  84
  85 /* X86_TUNE_MOVX: Enable to zero extend integer registers to avoid
  86    partial dependencies.  */
  87 DEF_TUNE (X86_TUNE_MOVX, "movx",
  88           m_PPRO | m_P4_NOCONA | m_CORE2 | m_NEHALEM  | m_SANDYBRIDGE
  89           | m_BONNELL | m_SILVERMONT | m_GOLDMONT | m_KNL | m_KNM | m_INTEL
  90           | m_GOLDMONT_PLUS | m_GEODE | m_AMD_MULTIPLE
  91           | m_CORE_AVX2 | m_TREMONT | m_GENERIC)
  92
  93 /* X86_TUNE_MEMORY_MISMATCH_STALL: Avoid partial stores that are followed by
  94    full sized loads.  */
  95 DEF_TUNE (X86_TUNE_MEMORY_MISMATCH_STALL, "memory_mismatch_stall",
  96           m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_INTEL
  97           | m_KNL | m_KNM | m_GOLDMONT | m_GOLDMONT_PLUS | m_AMD_MULTIPLE
  98           | m_TREMONT | m_GENERIC)
  99
 100 /* X86_TUNE_FUSE_CMP_AND_BRANCH_32: Fuse compare with a subsequent
 101    conditional jump instruction for 32 bit TARGET.  */
 102 DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_32, "fuse_cmp_and_branch_32",
 103           m_CORE_ALL | m_BDVER | m_ZNVER | m_GENERIC)
 104
 105 /* X86_TUNE_FUSE_CMP_AND_BRANCH_64: Fuse compare with a subsequent
 106    conditional jump instruction for TARGET_64BIT.  */
 107 DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_64, "fuse_cmp_and_branch_64",
 108           m_NEHALEM | m_SANDYBRIDGE | m_CORE_AVX2 | m_BDVER
 109           | m_ZNVER | m_GENERIC)
 110
 111 /* X86_TUNE_FUSE_CMP_AND_BRANCH_SOFLAGS: Fuse compare with a
 112    subsequent conditional jump instruction when the condition jump
 113    check sign flag (SF) or overflow flag (OF).  */
 114 DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_SOFLAGS, "fuse_cmp_and_branch_soflags",
 115           m_NEHALEM | m_SANDYBRIDGE | m_CORE_AVX2 | m_BDVER
 116           | m_ZNVER | m_GENERIC)
 117
 118 /* X86_TUNE_FUSE_ALU_AND_BRANCH: Fuse alu with a subsequent conditional
 119    jump instruction when the alu instruction produces the CCFLAG consumed by
 120    the conditional jump instruction. */
 121 DEF_TUNE (X86_TUNE_FUSE_ALU_AND_BRANCH, "fuse_alu_and_branch",
 122           m_SANDYBRIDGE | m_CORE_AVX2 | m_GENERIC)
 123
 124
 125 /*****************************************************************************/
 126 /* Function prologue, epilogue and function calling sequences.               */
 127 /*****************************************************************************/
 128
 129 /* X86_TUNE_ACCUMULATE_OUTGOING_ARGS: Allocate stack space for outgoing
 130    arguments in prologue/epilogue instead of separately for each call
 131    by push/pop instructions.
 132    This increase code size by about 5% in 32bit mode, less so in 64bit mode
 133    because parameters are passed in registers.  It is considerable
 134    win for targets without stack engine that prevents multple push operations
 135    to happen in parallel.  */
 136
 137 DEF_TUNE (X86_TUNE_ACCUMULATE_OUTGOING_ARGS, "accumulate_outgoing_args",
 138           m_PPRO | m_P4_NOCONA | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL
 139           | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT | m_ATHLON_K8)
 140
 141 /* X86_TUNE_PROLOGUE_USING_MOVE: Do not use push/pop in prologues that are
 142    considered on critical path.  */
 143 DEF_TUNE (X86_TUNE_PROLOGUE_USING_MOVE, "prologue_using_move",
 144           m_PPRO | m_ATHLON_K8)
 145
 146 /* X86_TUNE_PROLOGUE_USING_MOVE: Do not use push/pop in epilogues that are
 147    considered on critical path.  */
 148 DEF_TUNE (X86_TUNE_EPILOGUE_USING_MOVE, "epilogue_using_move",
 149           m_PPRO | m_ATHLON_K8)
 150
 151 /* X86_TUNE_USE_LEAVE: Use "leave" instruction in epilogues where it fits.  */
 152 DEF_TUNE (X86_TUNE_USE_LEAVE, "use_leave",
 153           m_386 | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC)
 154
 155 /* X86_TUNE_PUSH_MEMORY: Enable generation of "push mem" instructions.
 156    Some chips, like 486 and Pentium works faster with separate load
 157    and push instructions.  */
 158 DEF_TUNE (X86_TUNE_PUSH_MEMORY, "push_memory",
 159           m_386 | m_P4_NOCONA | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE
 160           | m_GENERIC)
 161
 162 /* X86_TUNE_SINGLE_PUSH: Enable if single push insn is preferred
 163    over esp subtraction.  */
 164 DEF_TUNE (X86_TUNE_SINGLE_PUSH, "single_push", m_386 | m_486 | m_PENT
 165           | m_LAKEMONT | m_K6_GEODE)
 166
 167 /* X86_TUNE_DOUBLE_PUSH. Enable if double push insn is preferred
 168    over esp subtraction.  */
 169 DEF_TUNE (X86_TUNE_DOUBLE_PUSH, "double_push", m_PENT | m_LAKEMONT
 170           | m_K6_GEODE)
 171
 172 /* X86_TUNE_SINGLE_POP: Enable if single pop insn is preferred
 173    over esp addition.  */
 174 DEF_TUNE (X86_TUNE_SINGLE_POP, "single_pop", m_386 | m_486 | m_PENT
 175           | m_LAKEMONT | m_PPRO)
 176
 177 /* X86_TUNE_DOUBLE_POP: Enable if double pop insn is preferred
 178    over esp addition.  */
 179 DEF_TUNE (X86_TUNE_DOUBLE_POP, "double_pop", m_PENT | m_LAKEMONT)
 180
 181 /*****************************************************************************/
 182 /* Branch predictor tuning                                                   */
 183 /*****************************************************************************/
 184
 185 /* X86_TUNE_PAD_SHORT_FUNCTION: Make every function to be at least 4
 186    instructions long.  */
 187 DEF_TUNE (X86_TUNE_PAD_SHORT_FUNCTION, "pad_short_function", m_BONNELL)
 188
 189 /* X86_TUNE_PAD_RETURNS: Place NOP before every RET that is a destination
 190    of conditional jump or directly preceded by other jump instruction.
 191    This is important for AND K8-AMDFAM10 because the branch prediction
 192    architecture expect at most one jump per 2 byte window.  Failing to
 193    pad returns leads to misaligned return stack.  */
 194 DEF_TUNE (X86_TUNE_PAD_RETURNS, "pad_returns",
 195           m_ATHLON_K8 | m_AMDFAM10)
 196
 197 /* X86_TUNE_FOUR_JUMP_LIMIT: Some CPU cores are not able to predict more
 198    than 4 branch instructions in the 16 byte window.  */
 199 DEF_TUNE (X86_TUNE_FOUR_JUMP_LIMIT, "four_jump_limit",
 200           m_PPRO | m_P4_NOCONA | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM
 201           | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT | m_INTEL | m_ATHLON_K8
 202           | m_AMDFAM10)
 203
 204 /*****************************************************************************/
 205 /* Integer instruction selection tuning                                      */
 206 /*****************************************************************************/
 207
 208 /* X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL: Enable software prefetching
 209    at -O3.  For the moment, the prefetching seems badly tuned for Intel
 210    chips.  */
 211 DEF_TUNE (X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL, "software_prefetching_beneficial",
 212           m_K6_GEODE | m_ATHLON_K8 | m_AMDFAM10 | m_BDVER | m_BTVER)
 213
 214 /* X86_TUNE_LCP_STALL: Avoid an expensive length-changing prefix stall
 215    on 16-bit immediate moves into memory on Core2 and Corei7.  */
 216 DEF_TUNE (X86_TUNE_LCP_STALL, "lcp_stall", m_CORE_ALL | m_GENERIC)
 217
 218 /* X86_TUNE_READ_MODIFY: Enable use of read-modify instructions such
 219    as "add mem, reg".  */
 220 DEF_TUNE (X86_TUNE_READ_MODIFY, "read_modify", ~(m_PENT | m_LAKEMONT | m_PPRO))
 221
 222 /* X86_TUNE_USE_INCDEC: Enable use of inc/dec instructions.
 223
 224    Core2 and nehalem has stall of 7 cycles for partial flag register stalls.
 225    Sandy bridge and Ivy bridge generate extra uop.  On Haswell this extra uop
 226    is output only when the values needs to be really merged, which is not
 227    done by GCC generated code.  */
 228 DEF_TUNE (X86_TUNE_USE_INCDEC, "use_incdec",
 229           ~(m_P4_NOCONA | m_CORE2 | m_NEHALEM  | m_SANDYBRIDGE
 230             | m_BONNELL | m_SILVERMONT | m_INTEL |  m_KNL | m_KNM | m_GOLDMONT
 231             | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC))
 232
 233 /* X86_TUNE_INTEGER_DFMODE_MOVES: Enable if integer moves are preferred
 234    for DFmode copies */
 235 DEF_TUNE (X86_TUNE_INTEGER_DFMODE_MOVES, "integer_dfmode_moves",
 236           ~(m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT
 237             | m_KNL | m_KNM | m_INTEL | m_GEODE | m_AMD_MULTIPLE | m_GOLDMONT
 238             | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC))
 239
 240 /* X86_TUNE_OPT_AGU: Optimize for Address Generation Unit. This flag
 241    will impact LEA instruction selection. */
 242 DEF_TUNE (X86_TUNE_OPT_AGU, "opt_agu", m_BONNELL | m_SILVERMONT | m_KNL
 243          | m_KNM | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT | m_INTEL)
 244
 245 /* X86_TUNE_AVOID_LEA_FOR_ADDR: Avoid lea for address computation.  */
 246 DEF_TUNE (X86_TUNE_AVOID_LEA_FOR_ADDR, "avoid_lea_for_addr",
 247           m_BONNELL | m_SILVERMONT | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT
 248           | m_KNL | m_KNM)
 249
 250 /* X86_TUNE_SLOW_IMUL_IMM32_MEM: Imul of 32-bit constant and memory is
 251    vector path on AMD machines.
 252    FIXME: Do we need to enable this for core? */
 253 DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM32_MEM, "slow_imul_imm32_mem",
 254           m_K8 | m_AMDFAM10)
 255
 256 /* X86_TUNE_SLOW_IMUL_IMM8: Imul of 8-bit constant is vector path on AMD
 257    machines.
 258    FIXME: Do we need to enable this for core? */
 259 DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM8, "slow_imul_imm8",
 260           m_K8 | m_AMDFAM10)
 261
 262 /* X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE: Try to avoid memory operands for
 263    a conditional move.  */
 264 DEF_TUNE (X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE, "avoid_mem_opnd_for_cmove",
 265           m_BONNELL | m_SILVERMONT | m_GOLDMONT | m_GOLDMONT_PLUS | m_KNL
 266           | m_KNM | m_TREMONT | m_INTEL)
 267
 268 /* X86_TUNE_SINGLE_STRINGOP: Enable use of single string operations, such
 269    as MOVS and STOS (without a REP prefix) to move/set sequences of bytes.  */
 270 DEF_TUNE (X86_TUNE_SINGLE_STRINGOP, "single_stringop", m_386 | m_P4_NOCONA)
 271
 272 /* X86_TUNE_MISALIGNED_MOVE_STRING_PRO_EPILOGUES: Enable generation of
 273    compact prologues and epilogues by issuing a misaligned moves.  This
 274    requires target to handle misaligned moves and partial memory stalls
 275    reasonably well.
 276    FIXME: This may actualy be a win on more targets than listed here.  */
 277 DEF_TUNE (X86_TUNE_MISALIGNED_MOVE_STRING_PRO_EPILOGUES,
 278           "misaligned_move_string_pro_epilogues",
 279           m_386 | m_486 | m_CORE_ALL | m_AMD_MULTIPLE | m_GENERIC)
 280
 281 /* X86_TUNE_USE_SAHF: Controls use of SAHF.  */
 282 DEF_TUNE (X86_TUNE_USE_SAHF, "use_sahf",
 283           m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT
 284           | m_KNL | m_KNM | m_INTEL | m_K6_GEODE | m_K8 | m_AMDFAM10 | m_BDVER
 285           | m_BTVER | m_ZNVER | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT
 286           | m_GENERIC)
 287
 288 /* X86_TUNE_USE_CLTD: Controls use of CLTD and CTQO instructions.  */
 289 DEF_TUNE (X86_TUNE_USE_CLTD, "use_cltd",
 290           ~(m_PENT | m_LAKEMONT | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL
 291             | m_K6 | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT))
 292
 293 /* X86_TUNE_USE_BT: Enable use of BT (bit test) instructions.  */
 294 DEF_TUNE (X86_TUNE_USE_BT, "use_bt",
 295           m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_INTEL
 296           | m_LAKEMONT | m_AMD_MULTIPLE | m_GOLDMONT | m_GOLDMONT_PLUS
 297           | m_TREMONT | m_GENERIC)
 298
 299 /* X86_TUNE_AVOID_FALSE_DEP_FOR_BMI: Avoid false dependency
 300    for bit-manipulation instructions.  */
 301 DEF_TUNE (X86_TUNE_AVOID_FALSE_DEP_FOR_BMI, "avoid_false_dep_for_bmi",
 302           m_SANDYBRIDGE | m_CORE_AVX2 | m_GENERIC)
 303
 304 /* X86_TUNE_ADJUST_UNROLL: This enables adjusting the unroll factor based
 305    on hardware capabilities. Bdver3 hardware has a loop buffer which makes
 306    unrolling small loop less important. For, such architectures we adjust
 307    the unroll factor so that the unrolled loop fits the loop buffer.  */
 308 DEF_TUNE (X86_TUNE_ADJUST_UNROLL, "adjust_unroll_factor", m_BDVER3 | m_BDVER4)
 309
 310 /* X86_TUNE_ONE_IF_CONV_INSNS: Restrict a number of cmov insns in
 311    if-converted sequence to one.  */
 312 DEF_TUNE (X86_TUNE_ONE_IF_CONV_INSN, "one_if_conv_insn",
 313           m_SILVERMONT | m_KNL | m_KNM | m_INTEL | m_CORE_ALL | m_GOLDMONT
 314           | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC)
 315
 316 /*****************************************************************************/
 317 /* 387 instruction selection tuning                                          */
 318 /*****************************************************************************/
 319
 320 /* X86_TUNE_USE_HIMODE_FIOP: Enables use of x87 instructions with 16bit
 321    integer operand.
 322    FIXME: Why this is disabled for modern chips?  */
 323 DEF_TUNE (X86_TUNE_USE_HIMODE_FIOP, "use_himode_fiop",
 324           m_386 | m_486 | m_K6_GEODE)
 325
 326 /* X86_TUNE_USE_SIMODE_FIOP: Enables use of x87 instructions with 32bit
 327    integer operand.  */
 328 DEF_TUNE (X86_TUNE_USE_SIMODE_FIOP, "use_simode_fiop",
 329           ~(m_PENT | m_LAKEMONT | m_PPRO | m_CORE_ALL | m_BONNELL
 330             | m_SILVERMONT | m_KNL | m_KNM | m_INTEL | m_AMD_MULTIPLE
 331             | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC))
 332
 333 /* X86_TUNE_USE_FFREEP: Use freep instruction instead of fstp.  */
 334 DEF_TUNE (X86_TUNE_USE_FFREEP, "use_ffreep", m_AMD_MULTIPLE)
 335
 336 /* X86_TUNE_EXT_80387_CONSTANTS: Use fancy 80387 constants, such as PI.  */
 337 DEF_TUNE (X86_TUNE_EXT_80387_CONSTANTS, "ext_80387_constants",
 338           m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT
 339           | m_KNL | m_KNM | m_INTEL | m_K6_GEODE | m_ATHLON_K8 | m_GOLDMONT
 340           | m_GOLDMONT_PLUS | m_TREMONT | m_GENERIC)
 341
 342 /*****************************************************************************/
 343 /* SSE instruction selection tuning                                          */
 344 /*****************************************************************************/
 345
 346 /* X86_TUNE_GENERAL_REGS_SSE_SPILL: Try to spill general regs to SSE
 347    regs instead of memory.  */
 348 DEF_TUNE (X86_TUNE_GENERAL_REGS_SSE_SPILL, "general_regs_sse_spill",
 349           m_CORE_ALL)
 350
 351 /* X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL: Use movups for misaligned loads instead
 352    of a sequence loading registers by parts.  */
 353 DEF_TUNE (X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL, "sse_unaligned_load_optimal",
 354           m_NEHALEM | m_SANDYBRIDGE | m_CORE_AVX2 | m_SILVERMONT | m_KNL | m_KNM
 355           | m_INTEL | m_GOLDMONT | m_GOLDMONT_PLUS
 356           | m_TREMONT | m_AMDFAM10 | m_BDVER | m_BTVER | m_ZNVER | m_GENERIC)
 357
 358 /* X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL: Use movups for misaligned stores instead
 359    of a sequence loading registers by parts.  */
 360 DEF_TUNE (X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL, "sse_unaligned_store_optimal",
 361           m_NEHALEM | m_SANDYBRIDGE | m_CORE_AVX2 | m_SILVERMONT | m_KNL | m_KNM
 362           | m_INTEL | m_GOLDMONT | m_GOLDMONT_PLUS
 363           | m_TREMONT | m_BDVER | m_ZNVER | m_GENERIC)
 364
 365 /* Use packed single precision instructions where posisble.  I.e. movups instead
 366    of movupd.  */
 367 DEF_TUNE (X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL, "sse_packed_single_insn_optimal",
 368           m_BDVER | m_ZNVER)
 369
 370 /* X86_TUNE_SSE_TYPELESS_STORES: Always movaps/movups for 128bit stores.   */
 371 DEF_TUNE (X86_TUNE_SSE_TYPELESS_STORES, "sse_typeless_stores",
 372           m_AMD_MULTIPLE | m_CORE_ALL | m_GENERIC)
 373
 374 /* X86_TUNE_SSE_LOAD0_BY_PXOR: Always use pxor to load0 as opposed to
 375    xorps/xorpd and other variants.  */
 376 DEF_TUNE (X86_TUNE_SSE_LOAD0_BY_PXOR, "sse_load0_by_pxor",
 377           m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BDVER | m_BTVER | m_ZNVER
 378           | m_GENERIC)
 379
 380 /* X86_TUNE_INTER_UNIT_MOVES_TO_VEC: Enable moves in from integer
 381    to SSE registers.  If disabled, the moves will be done by storing
 382    the value to memory and reloading.
 383    Enable this flag for generic - the only relevant architecture preferring
 384    no inter-unit moves is Buldozer. While this makes small regression on SPECfp
 385    scores (sub 0.3%), disabling inter-unit moves penalizes noticeably hand
 386    written vectorized code which use i.e. _mm_set_epi16.  */
 387 DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_TO_VEC, "inter_unit_moves_to_vec",
 388           ~(m_ATHLON_K8 | m_AMDFAM10 | m_BDVER | m_BTVER))
 389
 390 /* X86_TUNE_INTER_UNIT_MOVES_TO_VEC: Enable moves in from SSE
 391    to integer registers.  If disabled, the moves will be done by storing
 392    the value to memory and reloading.  */
 393 DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_FROM_VEC, "inter_unit_moves_from_vec",
 394           ~m_ATHLON_K8)
 395
 396 /* X86_TUNE_INTER_UNIT_CONVERSIONS: Enable float<->integer conversions
 397    to use both SSE and integer registers at a same time.  */
 398 DEF_TUNE (X86_TUNE_INTER_UNIT_CONVERSIONS, "inter_unit_conversions",
 399           ~(m_AMDFAM10 | m_BDVER))
 400
 401 /* X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS: Try to split memory operand for
 402    fp converts to destination register.  */
 403 DEF_TUNE (X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS, "split_mem_opnd_for_fp_converts",
 404           m_SILVERMONT | m_KNL | m_KNM | m_GOLDMONT | m_GOLDMONT_PLUS
 405           | m_TREMONT | m_INTEL)
 406
 407 /* X86_TUNE_USE_VECTOR_FP_CONVERTS: Prefer vector packed SSE conversion
 408    from FP to FP.  This form of instructions avoids partial write to the
 409    destination.  */
 410 DEF_TUNE (X86_TUNE_USE_VECTOR_FP_CONVERTS, "use_vector_fp_converts",
 411           m_AMDFAM10)
 412
 413 /* X86_TUNE_USE_VECTOR_CONVERTS: Prefer vector packed SSE conversion
 414    from integer to FP. */
 415 DEF_TUNE (X86_TUNE_USE_VECTOR_CONVERTS, "use_vector_converts", m_AMDFAM10)
 416
 417 /* X86_TUNE_SLOW_SHUFB: Indicates tunings with slow pshufb instruction.  */
 418 DEF_TUNE (X86_TUNE_SLOW_PSHUFB, "slow_pshufb",
 419           m_BONNELL | m_SILVERMONT | m_KNL | m_KNM | m_GOLDMONT
 420           | m_GOLDMONT_PLUS | m_TREMONT | m_INTEL)
 421
 422 /* X86_TUNE_AVOID_4BYTE_PREFIXES: Avoid instructions requiring 4+ bytes of prefixes.  */
 423 DEF_TUNE (X86_TUNE_AVOID_4BYTE_PREFIXES, "avoid_4byte_prefixes",
 424           m_SILVERMONT | m_GOLDMONT | m_GOLDMONT_PLUS | m_TREMONT | m_INTEL)
 425
 426 /* X86_TUNE_USE_GATHER: Use gather instructions.  */
 427 DEF_TUNE (X86_TUNE_USE_GATHER, "use_gather",
 428           ~(m_ZNVER | m_GENERIC))
 429
 430 /* X86_TUNE_AVOID_128FMA_CHAINS: Avoid creating loops with tight 128bit or
 431    smaller FMA chain.  */
 432 DEF_TUNE (X86_TUNE_AVOID_128FMA_CHAINS, "avoid_fma_chains", m_ZNVER)
 433
 434 /*****************************************************************************/
 435 /* AVX instruction selection tuning (some of SSE flags affects AVX, too)     */
 436 /*****************************************************************************/
 437
 438 /* X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL: if false, unaligned loads are
 439    split.  */
 440 DEF_TUNE (X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL, "256_unaligned_load_optimal",
 441           ~(m_NEHALEM | m_SANDYBRIDGE | m_GENERIC))
 442
 443 /* X86_TUNE_AVX256_UNALIGNED_STORE_OPTIMAL: if false, unaligned stores are
 444    split.  */
 445 DEF_TUNE (X86_TUNE_AVX256_UNALIGNED_STORE_OPTIMAL, "256_unaligned_store_optimal",
 446           ~(m_NEHALEM | m_SANDYBRIDGE | m_BDVER | m_ZNVER1 | m_GENERIC))
 447
 448 /* X86_TUNE_AVX128_OPTIMAL: Enable 128-bit AVX instruction generation for
 449    the auto-vectorizer.  */
 450 DEF_TUNE (X86_TUNE_AVX128_OPTIMAL, "avx128_optimal", m_BDVER | m_BTVER2
 451           | m_ZNVER1)
 452
 453 /* X86_TUNE_AVX256_OPTIMAL: Use 256-bit AVX instructions instead of 512-bit AVX
 454    instructions in the auto-vectorizer.  */
 455 DEF_TUNE (X86_TUNE_AVX256_OPTIMAL, "avx256_optimal", m_CORE_AVX512)
 456
 457 /*****************************************************************************/
 458 /* Historical relics: tuning flags that helps a specific old CPU designs     */
 459 /*****************************************************************************/
 460
 461 /* X86_TUNE_DOUBLE_WITH_ADD: Use add instead of sal to double value in
 462    an integer register.  */
 463 DEF_TUNE (X86_TUNE_DOUBLE_WITH_ADD, "double_with_add", ~m_386)
 464
 465 /* X86_TUNE_ALWAYS_FANCY_MATH_387: controls use of fancy 387 operations,
 466    such as fsqrt, fprem, fsin, fcos, fsincos etc.
 467    Should be enabled for all targets that always has coprocesor.  */
 468 DEF_TUNE (X86_TUNE_ALWAYS_FANCY_MATH_387, "always_fancy_math_387",
 469           ~(m_386 | m_486 | m_LAKEMONT))
 470
 471 /* X86_TUNE_UNROLL_STRLEN: Produce (quite lame) unrolled sequence for
 472    inline strlen.  This affects only -minline-all-stringops mode. By
 473    default we always dispatch to a library since our internal strlen
 474    is bad.  */
 475 DEF_TUNE (X86_TUNE_UNROLL_STRLEN, "unroll_strlen", ~m_386)
 476
 477 /* X86_TUNE_SHIFT1: Enables use of short encoding of "sal reg" instead of
 478    longer "sal $1, reg".  */
 479 DEF_TUNE (X86_TUNE_SHIFT1, "shift1", ~m_486)
 480
 481 /* X86_TUNE_ZERO_EXTEND_WITH_AND: Use AND instruction instead
 482    of mozbl/movwl.  */
 483 DEF_TUNE (X86_TUNE_ZERO_EXTEND_WITH_AND, "zero_extend_with_and",
 484           m_486 | m_PENT)
 485
 486 /* X86_TUNE_PROMOTE_HIMODE_IMUL: Modern CPUs have same latency for HImode
 487    and SImode multiply, but 386 and 486 do HImode multiply faster.  */
 488 DEF_TUNE (X86_TUNE_PROMOTE_HIMODE_IMUL, "promote_himode_imul",
 489           ~(m_386 | m_486))
 490
 491 /* X86_TUNE_FAST_PREFIX: Enable demoting some 32bit or 64bit arithmetic
 492    into 16bit/8bit when resulting sequence is shorter.  For example
 493    for "and $-65536, reg" to 16bit store of 0.  */
 494 DEF_TUNE (X86_TUNE_FAST_PREFIX, "fast_prefix",
 495           ~(m_386 | m_486 | m_PENT | m_LAKEMONT))
 496
 497 /* X86_TUNE_READ_MODIFY_WRITE: Enable use of read modify write instructions
 498    such as "add $1, mem".  */
 499 DEF_TUNE (X86_TUNE_READ_MODIFY_WRITE, "read_modify_write",
 500           ~(m_PENT | m_LAKEMONT))
 501
 502 /* X86_TUNE_MOVE_M1_VIA_OR: On pentiums, it is faster to load -1 via OR
 503    than a MOV.  */
 504 DEF_TUNE (X86_TUNE_MOVE_M1_VIA_OR, "move_m1_via_or", m_PENT | m_LAKEMONT)
 505
 506 /* X86_TUNE_NOT_UNPAIRABLE: NOT is not pairable on Pentium, while XOR is,
 507    but one byte longer.  */
 508 DEF_TUNE (X86_TUNE_NOT_UNPAIRABLE, "not_unpairable", m_PENT | m_LAKEMONT)
 509
 510 /* X86_TUNE_PARTIAL_REG_STALL: Pentium pro, unlike later chips, handled
 511    use of partial registers by renaming.  This improved performance of 16bit
 512    code where upper halves of registers are not used.  It also leads to
 513    an penalty whenever a 16bit store is followed by 32bit use.  This flag
 514    disables production of such sequences in common cases.
 515    See also X86_TUNE_HIMODE_MATH.
 516
 517    In current implementation the partial register stalls are not eliminated
 518    very well - they can be introduced via subregs synthesized by combine
 519    and can happen in caller/callee saving sequences.  */
 520 DEF_TUNE (X86_TUNE_PARTIAL_REG_STALL, "partial_reg_stall", m_PPRO)
 521
 522 /* X86_TUNE_PROMOTE_QIMODE: When it is cheap, turn 8bit arithmetic to
 523    corresponding 32bit arithmetic.  */
 524 DEF_TUNE (X86_TUNE_PROMOTE_QIMODE, "promote_qimode",
 525           ~m_PPRO)
 526
 527 /* X86_TUNE_PROMOTE_HI_REGS: Same, but for 16bit artihmetic.  Again we avoid
 528    partial register stalls on PentiumPro targets. */
 529 DEF_TUNE (X86_TUNE_PROMOTE_HI_REGS, "promote_hi_regs", m_PPRO)
 530
 531 /* X86_TUNE_HIMODE_MATH: Enable use of 16bit arithmetic.
 532    On PPro this flag is meant to avoid partial register stalls.  */
 533 DEF_TUNE (X86_TUNE_HIMODE_MATH, "himode_math", ~m_PPRO)
 534
 535 /* X86_TUNE_SPLIT_LONG_MOVES: Avoid instructions moving immediates
 536    directly to memory.  */
 537 DEF_TUNE (X86_TUNE_SPLIT_LONG_MOVES, "split_long_moves", m_PPRO)
 538
 539 /* X86_TUNE_USE_XCHGB: Use xchgb %rh,%rl instead of rolw/rorw $8,rx.  */
 540 DEF_TUNE (X86_TUNE_USE_XCHGB, "use_xchgb", m_PENT4)
 541
 542 /* X86_TUNE_USE_MOV0: Use "mov $0, reg" instead of "xor reg, reg" to clear
 543    integer register.  */
 544 DEF_TUNE (X86_TUNE_USE_MOV0, "use_mov0", m_K6)
 545
 546 /* X86_TUNE_NOT_VECTORMODE: On AMD K6, NOT is vector decoded with memory
 547    operand that cannot be represented using a modRM byte.  The XOR
 548    replacement is long decoded, so this split helps here as well.  */
 549 DEF_TUNE (X86_TUNE_NOT_VECTORMODE, "not_vectormode", m_K6)
 550
 551 /* X86_TUNE_AVOID_VECTOR_DECODE: Enable splitters that avoid vector decoded
 552    forms of instructions on K8 targets.  */
 553 DEF_TUNE (X86_TUNE_AVOID_VECTOR_DECODE, "avoid_vector_decode",
 554           m_K8)
 555
 556 /*****************************************************************************/
 557 /* This never worked well before.                                            */
 558 /*****************************************************************************/
 559
 560 /* X86_TUNE_BRANCH_PREDICTION_HINTS: Branch hints were put in P4 based
 561    on simulation result. But after P4 was made, no performance benefit
 562    was observed with branch hints.  It also increases the code size.
 563    As a result, icc never generates branch hints.  */
 564 DEF_TUNE (X86_TUNE_BRANCH_PREDICTION_HINTS, "branch_prediction_hints", 0U)
 565
 566 /* X86_TUNE_QIMODE_MATH: Enable use of 8bit arithmetic.  */
 567 DEF_TUNE (X86_TUNE_QIMODE_MATH, "qimode_math", ~0U)
 568
 569 /* X86_TUNE_PROMOTE_QI_REGS: This enables generic code that promotes all 8bit
 570    arithmetic to 32bit via PROMOTE_MODE macro.  This code generation scheme
 571    is usually used for RISC targets.  */
 572 DEF_TUNE (X86_TUNE_PROMOTE_QI_REGS, "promote_qi_regs", 0U)
 573
 574 /* X86_TUNE_EMIT_VZEROUPPER: This enables vzeroupper instruction insertion
 575    before a transfer of control flow out of the function.  */
 576 DEF_TUNE (X86_TUNE_EMIT_VZEROUPPER, "emit_vzeroupper", ~m_KNL)