| /* Definitions of x86 tunable features. |
| Copyright (C) 2013-2014 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* 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_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_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_SILVERMONT |
| | m_INTEL | 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_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_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_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_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_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_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_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_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) |
| |
| /* 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_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_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_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_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_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_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_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_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_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) |
| |
| /*****************************************************************************/ |
| /* 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_INTEL | 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) |
