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/* Definitions of x86 tunable features.

   Copyright (C) 2013-2015 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 3, or (at your option)

any later version.

GCC is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License and

a copy of the GCC Runtime Library Exception along with this program;

see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

.  */

/* Tuning for a given CPU XXXX consists of:

    - adding new CPU into:

	- adding PROCESSOR_XXX to processor_type (in i386.h)

	- possibly adding XXX into CPU attribute in i386.md

	- adding XXX to processor_alias_table (in i386.c)

    - introducing ix86_XXX_cost in i386.c

	- Stringop generation table can be build based on test_stringop

	- script (once rest of tuning is complete)

    - designing a scheduler model in

	- XXXX.md file

	- Updating ix86_issue_rate and ix86_adjust_cost in i386.md

	- possibly updating ia32_multipass_dfa_lookahead, ix86_sched_reorder

	  and ix86_sched_init_global if those tricks are needed.

    - Tunning the flags bellow. Those are split into sections and each

      section is very roughly ordered by importance.  */

/*****************************************************************************/

/* Scheduling flags. 					                     */

/*****************************************************************************/

/* X86_TUNE_SCHEDULE: Enable scheduling.  */

DEF_TUNE (X86_TUNE_SCHEDULE, "schedule",

          m_PENT | m_PPRO | m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_INTEL

	  | m_KNL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC)

/* X86_TUNE_PARTIAL_REG_DEPENDENCY: Enable more register renaming

   on modern chips.  Preffer stores affecting whole integer register

   over partial stores.  For example preffer MOVZBL or MOVQ to load 8bit

   value over movb.  */

DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency",

          m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_INTEL

	  | m_KNL | m_AMD_MULTIPLE | m_GENERIC)

/* X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY: This knob promotes all store

   destinations to be 128bit to allow register renaming on 128bit SSE units,

   but usually results in one extra microop on 64bit SSE units.

   Experimental results shows that disabling this option on P4 brings over 20%

   SPECfp regression, while enabling it on K8 brings roughly 2.4% regression

   that can be partly masked by careful scheduling of moves.  */

DEF_TUNE (X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY, "sse_partial_reg_dependency",

          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_AMDFAM10

	  | m_BDVER | m_GENERIC)

/* X86_TUNE_SSE_SPLIT_REGS: Set for machines where the type and dependencies

   are resolved on SSE register parts instead of whole registers, so we may

   maintain just lower part of scalar values in proper format leaving the

   upper part undefined.  */

DEF_TUNE (X86_TUNE_SSE_SPLIT_REGS, "sse_split_regs", m_ATHLON_K8)

/* X86_TUNE_PARTIAL_FLAG_REG_STALL: this flag disables use of of flags

   set by instructions affecting just some flags (in particular shifts).

   This is because Core2 resolves dependencies on whole flags register

   and such sequences introduce false dependency on previous instruction

   setting full flags.

   The flags does not affect generation of INC and DEC that is controlled

   by X86_TUNE_USE_INCDEC.

   This flag may be dropped from generic once core2-corei5 machines are

   rare enough.  */

DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL, "partial_flag_reg_stall",

          m_CORE2 | m_GENERIC)

/* X86_TUNE_MOVX: Enable to zero extend integer registers to avoid

   partial dependencies.  */

DEF_TUNE (X86_TUNE_MOVX, "movx",

          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT

	  | m_KNL | m_INTEL | m_GEODE | m_AMD_MULTIPLE  | m_GENERIC)

/* X86_TUNE_MEMORY_MISMATCH_STALL: Avoid partial stores that are followed by

   full sized loads.  */

DEF_TUNE (X86_TUNE_MEMORY_MISMATCH_STALL, "memory_mismatch_stall",

          m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_INTEL

	  | m_KNL | m_AMD_MULTIPLE | m_GENERIC)

/* X86_TUNE_FUSE_CMP_AND_BRANCH_32: Fuse compare with a subsequent

   conditional jump instruction for 32 bit TARGET.

   FIXME: revisit for generic.  */

DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_32, "fuse_cmp_and_branch_32",

          m_CORE_ALL | m_BDVER)

/* X86_TUNE_FUSE_CMP_AND_BRANCH_64: Fuse compare with a subsequent

   conditional jump instruction for TARGET_64BIT.

   FIXME: revisit for generic.  */

DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_64, "fuse_cmp_and_branch_64",

          m_NEHALEM | m_SANDYBRIDGE | m_HASWELL | m_BDVER)

/* X86_TUNE_FUSE_CMP_AND_BRANCH_SOFLAGS: Fuse compare with a

   subsequent conditional jump instruction when the condition jump

   check sign flag (SF) or overflow flag (OF).  */

DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH_SOFLAGS, "fuse_cmp_and_branch_soflags",

          m_NEHALEM | m_SANDYBRIDGE | m_HASWELL | m_BDVER)

/* X86_TUNE_FUSE_ALU_AND_BRANCH: Fuse alu with a subsequent conditional

   jump instruction when the alu instruction produces the CCFLAG consumed by

   the conditional jump instruction. */

DEF_TUNE (X86_TUNE_FUSE_ALU_AND_BRANCH, "fuse_alu_and_branch",

          m_SANDYBRIDGE | m_HASWELL)

/* X86_TUNE_REASSOC_INT_TO_PARALLEL: Try to produce parallel computations

   during reassociation of integer computation.  */

DEF_TUNE (X86_TUNE_REASSOC_INT_TO_PARALLEL, "reassoc_int_to_parallel",

          m_BONNELL)

/* X86_TUNE_REASSOC_FP_TO_PARALLEL: Try to produce parallel computations

   during reassociation of fp computation.  */

DEF_TUNE (X86_TUNE_REASSOC_FP_TO_PARALLEL, "reassoc_fp_to_parallel",

          m_BONNELL | m_SILVERMONT | m_HASWELL | m_KNL |m_INTEL | m_BDVER1

	  | m_BDVER2 | m_GENERIC)

/*****************************************************************************/

/* Function prologue, epilogue and function calling sequences.               */

/*****************************************************************************/

/* X86_TUNE_ACCUMULATE_OUTGOING_ARGS: Allocate stack space for outgoing

   arguments in prologue/epilogue instead of separately for each call

   by push/pop instructions.

   This increase code size by about 5% in 32bit mode, less so in 64bit mode

   because parameters are passed in registers.  It is considerable

   win for targets without stack engine that prevents multple push operations

   to happen in parallel.

   FIXME: the flags is incorrectly enabled for amdfam10, Bulldozer,

   Bobcat and Generic.  This is because disabling it causes large

   regression on mgrid due to IRA limitation leading to unecessary

   use of the frame pointer in 32bit mode.  */

DEF_TUNE (X86_TUNE_ACCUMULATE_OUTGOING_ARGS, "accumulate_outgoing_args",

	  m_PPRO | m_P4_NOCONA | m_BONNELL | m_SILVERMONT | m_KNL | m_INTEL

	  | m_ATHLON_K8)

/* X86_TUNE_PROLOGUE_USING_MOVE: Do not use push/pop in prologues that are

   considered on critical path.  */

DEF_TUNE (X86_TUNE_PROLOGUE_USING_MOVE, "prologue_using_move",

          m_PPRO | m_ATHLON_K8)

/* X86_TUNE_PROLOGUE_USING_MOVE: Do not use push/pop in epilogues that are

   considered on critical path.  */

DEF_TUNE (X86_TUNE_EPILOGUE_USING_MOVE, "epilogue_using_move",

          m_PPRO | m_ATHLON_K8)

/* X86_TUNE_USE_LEAVE: Use "leave" instruction in epilogues where it fits.  */

DEF_TUNE (X86_TUNE_USE_LEAVE, "use_leave",

	  m_386 | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC)

/* X86_TUNE_PUSH_MEMORY: Enable generation of "push mem" instructions.

   Some chips, like 486 and Pentium works faster with separate load

   and push instructions.  */

DEF_TUNE (X86_TUNE_PUSH_MEMORY, "push_memory",

          m_386 | m_P4_NOCONA | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE

          | m_GENERIC)

/* X86_TUNE_SINGLE_PUSH: Enable if single push insn is preferred

   over esp subtraction.  */

DEF_TUNE (X86_TUNE_SINGLE_PUSH, "single_push", m_386 | m_486 | m_PENT

          | m_K6_GEODE)

/* X86_TUNE_DOUBLE_PUSH. Enable if double push insn is preferred

   over esp subtraction.  */

DEF_TUNE (X86_TUNE_DOUBLE_PUSH, "double_push", m_PENT | m_K6_GEODE)

/* X86_TUNE_SINGLE_POP: Enable if single pop insn is preferred

   over esp addition.  */

DEF_TUNE (X86_TUNE_SINGLE_POP, "single_pop", m_386 | m_486 | m_PENT | m_PPRO)

/* X86_TUNE_DOUBLE_POP: Enable if double pop insn is preferred

   over esp addition.  */

DEF_TUNE (X86_TUNE_DOUBLE_POP, "double_pop", m_PENT)

/*****************************************************************************/

/* Branch predictor tuning  		                                     */

/*****************************************************************************/

/* X86_TUNE_PAD_SHORT_FUNCTION: Make every function to be at least 4

   instructions long.  */

DEF_TUNE (X86_TUNE_PAD_SHORT_FUNCTION, "pad_short_function", m_BONNELL)

/* X86_TUNE_PAD_RETURNS: Place NOP before every RET that is a destination

   of conditional jump or directly preceded by other jump instruction.

   This is important for AND K8-AMDFAM10 because the branch prediction

   architecture expect at most one jump per 2 byte window.  Failing to

   pad returns leads to misaligned return stack.  */

DEF_TUNE (X86_TUNE_PAD_RETURNS, "pad_returns",

          m_ATHLON_K8 | m_AMDFAM10 | m_GENERIC)

/* X86_TUNE_FOUR_JUMP_LIMIT: Some CPU cores are not able to predict more

   than 4 branch instructions in the 16 byte window.  */

DEF_TUNE (X86_TUNE_FOUR_JUMP_LIMIT, "four_jump_limit",

          m_PPRO | m_P4_NOCONA | m_BONNELL | m_SILVERMONT | m_KNL |m_INTEL |

	  m_ATHLON_K8 | m_AMDFAM10)

/*****************************************************************************/

/* Integer instruction selection tuning                                      */

/*****************************************************************************/

/* X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL: Enable software prefetching

   at -O3.  For the moment, the prefetching seems badly tuned for Intel

   chips.  */

DEF_TUNE (X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL, "software_prefetching_beneficial",

          m_K6_GEODE | m_AMD_MULTIPLE)

/* X86_TUNE_LCP_STALL: Avoid an expensive length-changing prefix stall

   on 16-bit immediate moves into memory on Core2 and Corei7.  */

DEF_TUNE (X86_TUNE_LCP_STALL, "lcp_stall", m_CORE_ALL | m_GENERIC)

/* X86_TUNE_READ_MODIFY: Enable use of read-modify instructions such

   as "add mem, reg".  */

DEF_TUNE (X86_TUNE_READ_MODIFY, "read_modify", ~(m_PENT | m_PPRO))

/* X86_TUNE_USE_INCDEC: Enable use of inc/dec instructions.   */

DEF_TUNE (X86_TUNE_USE_INCDEC, "use_incdec",

          ~(m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_INTEL

	   |  m_KNL | m_GENERIC))

/* X86_TUNE_INTEGER_DFMODE_MOVES: Enable if integer moves are preferred

   for DFmode copies */

DEF_TUNE (X86_TUNE_INTEGER_DFMODE_MOVES, "integer_dfmode_moves",

          ~(m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT

	    | m_KNL | m_INTEL | m_GEODE | m_AMD_MULTIPLE | m_GENERIC))

/* X86_TUNE_OPT_AGU: Optimize for Address Generation Unit. This flag

   will impact LEA instruction selection. */

DEF_TUNE (X86_TUNE_OPT_AGU, "opt_agu", m_BONNELL | m_SILVERMONT | m_KNL

	  | m_INTEL)

/* X86_TUNE_AVOID_LEA_FOR_ADDR: Avoid lea for address computation.  */

DEF_TUNE (X86_TUNE_AVOID_LEA_FOR_ADDR, "avoid_lea_for_addr",

	  m_BONNELL | m_SILVERMONT | m_KNL)

/* X86_TUNE_SLOW_IMUL_IMM32_MEM: Imul of 32-bit constant and memory is

   vector path on AMD machines.

   FIXME: Do we need to enable this for core? */

DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM32_MEM, "slow_imul_imm32_mem",

          m_K8 | m_AMDFAM10)

/* X86_TUNE_SLOW_IMUL_IMM8: Imul of 8-bit constant is vector path on AMD

   machines.

   FIXME: Do we need to enable this for core? */

DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM8, "slow_imul_imm8",

          m_K8 | m_AMDFAM10)

/* X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE: Try to avoid memory operands for

   a conditional move.  */

DEF_TUNE (X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE, "avoid_mem_opnd_for_cmove",

	  m_BONNELL | m_SILVERMONT | m_KNL | m_INTEL)

/* X86_TUNE_SINGLE_STRINGOP: Enable use of single string operations, such

   as MOVS and STOS (without a REP prefix) to move/set sequences of bytes.  */

DEF_TUNE (X86_TUNE_SINGLE_STRINGOP, "single_stringop", m_386 | m_P4_NOCONA)

/* X86_TUNE_MISALIGNED_MOVE_STRING_PRO_EPILOGUES: Enable generation of

   compact prologues and epilogues by issuing a misaligned moves.  This

   requires target to handle misaligned moves and partial memory stalls

   reasonably well.

   FIXME: This may actualy be a win on more targets than listed here.  */

DEF_TUNE (X86_TUNE_MISALIGNED_MOVE_STRING_PRO_EPILOGUES,

	  "misaligned_move_string_pro_epilogues",

	  m_386 | m_486 | m_CORE_ALL | m_AMD_MULTIPLE | m_GENERIC)

/* X86_TUNE_USE_SAHF: Controls use of SAHF.  */

DEF_TUNE (X86_TUNE_USE_SAHF, "use_sahf",

          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT

	  | m_KNL | m_INTEL | m_K6_GEODE | m_K8 | m_AMDFAM10 | m_BDVER

	  | m_BTVER | m_GENERIC)

/* X86_TUNE_USE_CLTD: Controls use of CLTD and CTQO instructions.  */

DEF_TUNE (X86_TUNE_USE_CLTD, "use_cltd",

	  ~(m_PENT | m_BONNELL | m_SILVERMONT | m_KNL | m_INTEL  | m_K6))

/* X86_TUNE_USE_BT: Enable use of BT (bit test) instructions.  */

DEF_TUNE (X86_TUNE_USE_BT, "use_bt",

          m_CORE_ALL | m_BONNELL | m_SILVERMONT | m_KNL | m_INTEL

	  | m_AMD_MULTIPLE | m_GENERIC)

/*****************************************************************************/

/* 387 instruction selection tuning                                          */

/*****************************************************************************/

/* X86_TUNE_USE_HIMODE_FIOP: Enables use of x87 instructions with 16bit

   integer operand.

   FIXME: Why this is disabled for modern chips?  */

DEF_TUNE (X86_TUNE_USE_HIMODE_FIOP, "use_himode_fiop",

          m_386 | m_486 | m_K6_GEODE)

/* X86_TUNE_USE_SIMODE_FIOP: Enables use of x87 instructions with 32bit

   integer operand.  */

DEF_TUNE (X86_TUNE_USE_SIMODE_FIOP, "use_simode_fiop",

          ~(m_PENT | m_PPRO | m_CORE_ALL | m_BONNELL | m_SILVERMONT

	    | m_KNL | m_INTEL | m_AMD_MULTIPLE | m_GENERIC))

/* X86_TUNE_USE_FFREEP: Use freep instruction instead of fstp.  */

DEF_TUNE (X86_TUNE_USE_FFREEP, "use_ffreep", m_AMD_MULTIPLE)

/* X86_TUNE_EXT_80387_CONSTANTS: Use fancy 80387 constants, such as PI.  */

DEF_TUNE (X86_TUNE_EXT_80387_CONSTANTS, "ext_80387_constants",

          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BONNELL | m_SILVERMONT

	  | m_KNL | m_INTEL | m_K6_GEODE | m_ATHLON_K8 | m_GENERIC)

/*****************************************************************************/

/* SSE instruction selection tuning                                          */

/*****************************************************************************/

/* X86_TUNE_VECTORIZE_DOUBLE: Enable double precision vector

   instructions.  */

DEF_TUNE (X86_TUNE_VECTORIZE_DOUBLE, "vectorize_double", ~m_BONNELL)

/* X86_TUNE_GENERAL_REGS_SSE_SPILL: Try to spill general regs to SSE

   regs instead of memory.  */

DEF_TUNE (X86_TUNE_GENERAL_REGS_SSE_SPILL, "general_regs_sse_spill",

          m_CORE_ALL)

/* X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL: Use movups for misaligned loads instead

   of a sequence loading registers by parts.  */

DEF_TUNE (X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL, "sse_unaligned_load_optimal",

          m_NEHALEM | m_SANDYBRIDGE | m_HASWELL | m_AMDFAM10 | m_BDVER

	  | m_BTVER | m_SILVERMONT | m_KNL | m_INTEL | m_GENERIC)

/* X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL: Use movups for misaligned stores instead

   of a sequence loading registers by parts.  */

DEF_TUNE (X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL, "sse_unaligned_store_optimal",

          m_NEHALEM | m_SANDYBRIDGE | m_HASWELL | m_BDVER | m_SILVERMONT

	  | m_KNL | m_INTEL | m_GENERIC)

/* Use packed single precision instructions where posisble.  I.e. movups instead

   of movupd.  */

DEF_TUNE (X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL, "sse_packed_single_insn_optimal",

          m_BDVER)

/* X86_TUNE_SSE_TYPELESS_STORES: Always movaps/movups for 128bit stores.   */

DEF_TUNE (X86_TUNE_SSE_TYPELESS_STORES, "sse_typeless_stores",

	  m_AMD_MULTIPLE | m_CORE_ALL | m_GENERIC)

/* X86_TUNE_SSE_LOAD0_BY_PXOR: Always use pxor to load0 as opposed to

   xorps/xorpd and other variants.  */

DEF_TUNE (X86_TUNE_SSE_LOAD0_BY_PXOR, "sse_load0_by_pxor",

	  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_BDVER | m_BTVER | m_GENERIC)

/* X86_TUNE_INTER_UNIT_MOVES_TO_VEC: Enable moves in from integer

   to SSE registers.  If disabled, the moves will be done by storing

   the value to memory and reloading.  */

DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_TO_VEC, "inter_unit_moves_to_vec",

          ~(m_AMD_MULTIPLE | m_GENERIC))

/* X86_TUNE_INTER_UNIT_MOVES_TO_VEC: Enable moves in from SSE

   to integer registers.  If disabled, the moves will be done by storing

   the value to memory and reloading.  */

DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_FROM_VEC, "inter_unit_moves_from_vec",

          ~m_ATHLON_K8)

/* X86_TUNE_INTER_UNIT_CONVERSIONS: Enable float<->integer conversions

   to use both SSE and integer registers at a same time.

   FIXME: revisit importance of this for generic.  */

DEF_TUNE (X86_TUNE_INTER_UNIT_CONVERSIONS, "inter_unit_conversions",

          ~(m_AMDFAM10 | m_BDVER))

/* X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS: Try to split memory operand for

   fp converts to destination register.  */

DEF_TUNE (X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS, "split_mem_opnd_for_fp_converts",

          m_SILVERMONT | m_KNL | m_INTEL)

/* X86_TUNE_USE_VECTOR_FP_CONVERTS: Prefer vector packed SSE conversion

   from FP to FP.  This form of instructions avoids partial write to the

   destination.  */

DEF_TUNE (X86_TUNE_USE_VECTOR_FP_CONVERTS, "use_vector_fp_converts",

          m_AMDFAM10)

/* X86_TUNE_USE_VECTOR_CONVERTS: Prefer vector packed SSE conversion

   from integer to FP. */

DEF_TUNE (X86_TUNE_USE_VECTOR_CONVERTS, "use_vector_converts", m_AMDFAM10)

/* X86_TUNE_SLOW_SHUFB: Indicates tunings with slow pshufb instruction.  */

DEF_TUNE (X86_TUNE_SLOW_PSHUFB, "slow_pshufb",

          m_BONNELL | m_SILVERMONT | m_KNL | m_INTEL)

/* X86_TUNE_VECTOR_PARALLEL_EXECUTION: Indicates tunings with ability to

   execute 2 or more vector instructions in parallel.  */

DEF_TUNE (X86_TUNE_VECTOR_PARALLEL_EXECUTION, "vec_parallel",

          m_NEHALEM | m_SANDYBRIDGE | m_HASWELL)

/* X86_TUNE_AVOID_4BYTE_PREFIXES: Avoid instructions requiring 4+ bytes of prefixes.  */

DEF_TUNE (X86_TUNE_AVOID_4BYTE_PREFIXES, "avoid_4byte_prefixes",

          m_SILVERMONT | m_INTEL)

/*****************************************************************************/

/* AVX instruction selection tuning (some of SSE flags affects AVX, too)     */

/*****************************************************************************/

/* X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL: if false, unaligned loads are

   split.  */

DEF_TUNE (X86_TUNE_AVX256_UNALIGNED_LOAD_OPTIMAL, "256_unaligned_load_optimal",

          ~(m_NEHALEM | m_SANDYBRIDGE | m_GENERIC))

/* X86_TUNE_AVX256_UNALIGNED_STORE_OPTIMAL: if false, unaligned stores are

   split.  */

DEF_TUNE (X86_TUNE_AVX256_UNALIGNED_STORE_OPTIMAL, "256_unaligned_store_optimal",

          ~(m_NEHALEM | m_SANDYBRIDGE | m_BDVER | m_GENERIC))

/* X86_TUNE_AVX128_OPTIMAL: Enable 128-bit AVX instruction generation for

   the auto-vectorizer.  */

DEF_TUNE (X86_TUNE_AVX128_OPTIMAL, "avx128_optimal", m_BDVER | m_BTVER2)

/*****************************************************************************/

/* Historical relics: tuning flags that helps a specific old CPU designs     */

/*****************************************************************************/

/* X86_TUNE_DOUBLE_WITH_ADD: Use add instead of sal to double value in

   an integer register.  */

DEF_TUNE (X86_TUNE_DOUBLE_WITH_ADD, "double_with_add", ~m_386)

/* X86_TUNE_ALWAYS_FANCY_MATH_387: controls use of fancy 387 operations,

   such as fsqrt, fprem, fsin, fcos, fsincos etc.

   Should be enabled for all targets that always has coprocesor.  */

DEF_TUNE (X86_TUNE_ALWAYS_FANCY_MATH_387, "always_fancy_math_387",

          ~(m_386 | m_486))

/* X86_TUNE_UNROLL_STRLEN: Produce (quite lame) unrolled sequence for

   inline strlen.  This affects only -minline-all-stringops mode. By

   default we always dispatch to a library since our internal strlen

   is bad.  */

DEF_TUNE (X86_TUNE_UNROLL_STRLEN, "unroll_strlen", ~m_386)

/* X86_TUNE_SHIFT1: Enables use of short encoding of "sal reg" instead of

   longer "sal $1, reg".  */

DEF_TUNE (X86_TUNE_SHIFT1, "shift1", ~m_486)

/* X86_TUNE_ZERO_EXTEND_WITH_AND: Use AND instruction instead

   of mozbl/movwl.  */

DEF_TUNE (X86_TUNE_ZERO_EXTEND_WITH_AND, "zero_extend_with_and",  m_486 | m_PENT)

/* X86_TUNE_PROMOTE_HIMODE_IMUL: Modern CPUs have same latency for HImode

   and SImode multiply, but 386 and 486 do HImode multiply faster.  */

DEF_TUNE (X86_TUNE_PROMOTE_HIMODE_IMUL, "promote_himode_imul",

          ~(m_386 | m_486))

/* X86_TUNE_FAST_PREFIX: Enable demoting some 32bit or 64bit arithmetic

   into 16bit/8bit when resulting sequence is shorter.  For example

   for "and $-65536, reg" to 16bit store of 0.  */

DEF_TUNE (X86_TUNE_FAST_PREFIX, "fast_prefix", ~(m_386 | m_486 | m_PENT))

/* X86_TUNE_READ_MODIFY_WRITE: Enable use of read modify write instructions

   such as "add $1, mem".  */

DEF_TUNE (X86_TUNE_READ_MODIFY_WRITE, "read_modify_write", ~m_PENT)

/* X86_TUNE_MOVE_M1_VIA_OR: On pentiums, it is faster to load -1 via OR

   than a MOV.  */

DEF_TUNE (X86_TUNE_MOVE_M1_VIA_OR, "move_m1_via_or", m_PENT)

/* X86_TUNE_NOT_UNPAIRABLE: NOT is not pairable on Pentium, while XOR is,

   but one byte longer.  */

DEF_TUNE (X86_TUNE_NOT_UNPAIRABLE, "not_unpairable", m_PENT)

/* X86_TUNE_PARTIAL_REG_STALL: Pentium pro, unlike later chips, handled

   use of partial registers by renaming.  This improved performance of 16bit

   code where upper halves of registers are not used.  It also leads to

   an penalty whenever a 16bit store is followed by 32bit use.  This flag

   disables production of such sequences in common cases.

   See also X86_TUNE_HIMODE_MATH.

   In current implementation the partial register stalls are not eliminated

   very well - they can be introduced via subregs synthesized by combine

   and can happen in caller/callee saving sequences.  */

DEF_TUNE (X86_TUNE_PARTIAL_REG_STALL, "partial_reg_stall", m_PPRO)

/* X86_TUNE_PROMOTE_QIMODE: When it is cheap, turn 8bit arithmetic to

   corresponding 32bit arithmetic.  */

DEF_TUNE (X86_TUNE_PROMOTE_QIMODE, "promote_qimode",

	  ~m_PPRO)

/* X86_TUNE_PROMOTE_HI_REGS: Same, but for 16bit artihmetic.  Again we avoid

   partial register stalls on PentiumPro targets. */

DEF_TUNE (X86_TUNE_PROMOTE_HI_REGS, "promote_hi_regs", m_PPRO)

/* X86_TUNE_HIMODE_MATH: Enable use of 16bit arithmetic.

   On PPro this flag is meant to avoid partial register stalls.  */

DEF_TUNE (X86_TUNE_HIMODE_MATH, "himode_math", ~m_PPRO)

/* X86_TUNE_SPLIT_LONG_MOVES: Avoid instructions moving immediates

   directly to memory.  */

DEF_TUNE (X86_TUNE_SPLIT_LONG_MOVES, "split_long_moves", m_PPRO)

/* X86_TUNE_USE_XCHGB: Use xchgb %rh,%rl instead of rolw/rorw $8,rx.  */

DEF_TUNE (X86_TUNE_USE_XCHGB, "use_xchgb", m_PENT4)

/* X86_TUNE_USE_MOV0: Use "mov $0, reg" instead of "xor reg, reg" to clear

   integer register.  */

DEF_TUNE (X86_TUNE_USE_MOV0, "use_mov0", m_K6)

/* X86_TUNE_NOT_VECTORMODE: On AMD K6, NOT is vector decoded with memory

   operand that cannot be represented using a modRM byte.  The XOR

   replacement is long decoded, so this split helps here as well.  */

DEF_TUNE (X86_TUNE_NOT_VECTORMODE, "not_vectormode", m_K6)

/* X86_TUNE_AVOID_VECTOR_DECODE: Enable splitters that avoid vector decoded

   forms of instructions on K8 targets.  */

DEF_TUNE (X86_TUNE_AVOID_VECTOR_DECODE, "avoid_vector_decode",

          m_K8)

/* X86_TUNE_AVOID_FALSE_DEP_FOR_BMI: Avoid false dependency

   for bit-manipulation instructions.  */

DEF_TUNE (X86_TUNE_AVOID_FALSE_DEP_FOR_BMI, "avoid_false_dep_for_bmi",

	  m_SANDYBRIDGE | m_HASWELL | m_GENERIC)

/*****************************************************************************/

/* This never worked well before.                                            */

/*****************************************************************************/

/* X86_TUNE_BRANCH_PREDICTION_HINTS: Branch hints were put in P4 based

   on simulation result. But after P4 was made, no performance benefit

   was observed with branch hints.  It also increases the code size.

   As a result, icc never generates branch hints.  */

DEF_TUNE (X86_TUNE_BRANCH_PREDICTION_HINTS, "branch_prediction_hints", 0)

/* X86_TUNE_QIMODE_MATH: Enable use of 8bit arithmetic.  */

DEF_TUNE (X86_TUNE_QIMODE_MATH, "qimode_math", ~0)

/* X86_TUNE_PROMOTE_QI_REGS: This enables generic code that promotes all 8bit

   arithmetic to 32bit via PROMOTE_MODE macro.  This code generation scheme

   is usually used for RISC targets.  */

DEF_TUNE (X86_TUNE_PROMOTE_QI_REGS, "promote_qi_regs", 0)

/* X86_TUNE_ADJUST_UNROLL: This enables adjusting the unroll factor based

   on hardware capabilities. Bdver3 hardware has a loop buffer which makes

   unrolling small loop less important. For, such architectures we adjust

   the unroll factor so that the unrolled loop fits the loop buffer.  */

DEF_TUNE (X86_TUNE_ADJUST_UNROLL, "adjust_unroll_factor", m_BDVER3 | m_BDVER4)