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Re: New parameters to control stringop expansion libcall strategy
- From: Michael Zolotukhin <michael dot v dot zolotukhin at gmail dot com>
- To: Xinliang David Li <davidxl at google dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Jan Hubicka <hubicka at ucw dot cz>, Teresa Johnson <tejohnson at google dot com>
- Date: Tue, 6 Aug 2013 12:46:34 +0400
- Subject: Re: New parameters to control stringop expansion libcall strategy
- References: <CAAkRFZ+muGUjANkKqbp8r4HvddywmRgz+xPbVAUbuU9rE7pC7Q at mail dot gmail dot com> <CAAkRFZ+eO3wq9vJhMG5FBc6Awb04+8PQKz44A0PJEpOo7TByfQ at mail dot gmail dot com> <20130805105658 dot GA5144 at msticlxl57 dot ims dot intel dot com> <CAAkRFZJNrW0WRJQwOUUz1NhHLXKiu44pwEkNSyJj70RNgCOY9w at mail dot gmail dot com>
There are still some formatting issues (like 8 spaces instead of a
tab, wrong indentation of do-loop and some other places) - to reveal
some of them you could use contrib/check_GNU_style.sh script.
But that was a nitpicking again:) Actually I wanted to ask whether
you're going to use this option for some performance experiments
involving memmov/memset - if so, probably you could tune existing
cost-models as well? Is it possible?
Michael
On 5 August 2013 20:44, Xinliang David Li <davidxl@google.com> wrote:
> thanks. Updated patch attached.
>
> David
>
> On Mon, Aug 5, 2013 at 3:57 AM, Michael V. Zolotukhin
> <michael.v.zolotukhin@gmail.com> wrote:
>> Hi,
>> This is a really convenient option, thanks for working on it.
>> I can't approve it as I'm not a maintainer, but it looks ok to me,
>> except fot a small nitpicking: afair, comments should end with
>> dot-space-space.
>>
>> Michael
>>
>> On 04 Aug 20:01, Xinliang David Li wrote:
>>> The attached is a new patch implementing the stringop inline strategy
>>> control using two new -m options:
>>>
>>> -mmemcpy-strategy=
>>> -mmemset-strategy=
>>>
>>> See changes in doc/invoke.texi for description of the new options. Example:
>>> -mmemcpy-strategy=rep_8byte:64:unaligned,unrolled_loop:2048:unaligned,libcall:-1:unaligned
>>>
>>> tells compiler to inline memcpy using rep_8byte when the size is no
>>> larger than 64 byte, using unrolled_loop when size is no larger than
>>> 2048, and for size > 2048, using library call. In all cases,
>>> destination alignment adjustment is not done.
>>>
>>> Tested on x86-64/linux. Ok for trunk?
>>>
>>> thanks,
>>>
>>> David
>>>
>>> 2013-08-02 Xinliang David Li <davidxl@google.com>
>>>
>>> * config/i386/stringop.def: New file.
>>> * config/i386/stringop.opt: New file.
>>> * config/i386/i386-opts.h: Include stringopt.def.
>>> * config/i386/i386.opt: Include stringopt.opt.
>>> * config/i386/i386.c (ix86_option_override_internal):
>>> Override default size based stringop inline strategies
>>> with options.
>>> * config/i386/i386.c (ix86_parse_stringop_strategy_string):
>>> New function.
>>>
>>> 2013-08-04 Xinliang David Li <davidxl@google.com>
>>>
>>> * testsuite/gcc.target/i386/memcpy-strategy-1.c: New test.
>>> * testsuite/gcc.target/i386/memcpy-strategy-2.c: Ditto.
>>> * testsuite/gcc.target/i386/memset-strategy-1.c: Ditto.
>>> * testsuite/gcc.target/i386/memcpy-strategy-3.c: Ditto.
>>>
>>>
>>>
>>>
>>> On Fri, Aug 2, 2013 at 9:21 PM, Xinliang David Li <davidxl@google.com> wrote:
>>> > On x86_64, when the expected size of memcpy/memset is known (e.g, with
>>> > FDO), libcall strategy is used with the size is > 8192. This value is
>>> > hard coded, which makes it hard to do performance tuning. This patch
>>> > adds two new parameters to do that. Potential usage includes
>>> > per-application libcall strategy min-size tuning based on summary data
>>> > with FDO (e.g, instruction workset size).
>>> >
>>> > Bootstrap and tested on x86_64/linux. Ok for trunk?
>>> >
>>> > thanks,
>>> >
>>> > David
>>> >
>>> >
>>> > 2013-08-02 Xinliang David Li <davidxl@google.com>
>>> >
>>> > * params.def: New parameters.
>>> > * config/i386/i386.c (ix86_option_override_internal):
>>> > Override default libcall size limit with parameters.
>>
>>> Index: config/i386/stringop.def
>>> ===================================================================
>>> --- config/i386/stringop.def (revision 0)
>>> +++ config/i386/stringop.def (revision 0)
>>> @@ -0,0 +1,42 @@
>>> +/* Definitions for option handling for IA-32.
>>> + Copyright (C) 2013 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.
>>> +
>>> +Under Section 7 of GPL version 3, you are granted additional
>>> +permissions described in the GCC Runtime Library Exception, version
>>> +3.1, as published by the Free Software Foundation.
>>> +
>>> +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/>. */
>>> +
>>> +DEF_ENUM
>>> +DEF_ALG (no_stringop, no_stringop)
>>> +DEF_ENUM
>>> +DEF_ALG (libcall, libcall)
>>> +DEF_ENUM
>>> +DEF_ALG (rep_prefix_1_byte, rep_byte)
>>> +DEF_ENUM
>>> +DEF_ALG (rep_prefix_4_byte, rep_4byte)
>>> +DEF_ENUM
>>> +DEF_ALG (rep_prefix_8_byte, rep_8byte)
>>> +DEF_ENUM
>>> +DEF_ALG (loop_1_byte, byte_loop)
>>> +DEF_ENUM
>>> +DEF_ALG (loop, loop)
>>> +DEF_ENUM
>>> +DEF_ALG (unrolled_loop, unrolled_loop)
>>> +DEF_ENUM
>>> +DEF_ALG (vector_loop, vector_loop)
>>> Index: config/i386/i386.opt
>>> ===================================================================
>>> --- config/i386/i386.opt (revision 201458)
>>> +++ config/i386/i386.opt (working copy)
>>> @@ -316,6 +316,14 @@ mstack-arg-probe
>>> Target Report Mask(STACK_PROBE) Save
>>> Enable stack probing
>>>
>>> +mmemcpy-strategy=
>>> +Target RejectNegative Joined Var(ix86_tune_memcpy_strategy)
>>> +Specify memcpy expansion strategy when expected size is known
>>> +
>>> +mmemset-strategy=
>>> +Target RejectNegative Joined Var(ix86_tune_memset_strategy)
>>> +Specify memset expansion strategy when expected size is known
>>> +
>>> mstringop-strategy=
>>> Target RejectNegative Joined Enum(stringop_alg) Var(ix86_stringop_alg) Init(no_stringop)
>>> Chose strategy to generate stringop using
>>> Index: config/i386/stringop.opt
>>> ===================================================================
>>> --- config/i386/stringop.opt (revision 0)
>>> +++ config/i386/stringop.opt (revision 0)
>>> @@ -0,0 +1,36 @@
>>> +/* Definitions for option handling for IA-32.
>>> + Copyright (C) 2013 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.
>>> +
>>> +Under Section 7 of GPL version 3, you are granted additional
>>> +permissions described in the GCC Runtime Library Exception, version
>>> +3.1, as published by the Free Software Foundation.
>>> +
>>> +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/>. */
>>> +
>>> +Enum(stringop_alg) String(rep_byte) Value(rep_prefix_1_byte)
>>> +
>>> +#undef DEF_ENUM
>>> +#define DEF_ENUM EnumValue
>>> +
>>> +#undef DEF_ALG
>>> +#define DEF_ALG(alg, name) Enum(stringop_alg) String(name) Value(alg)
>>> +
>>> +#include "stringop.def"
>>> +
>>> +#undef DEF_ENUM
>>> +#undef DEF_ALG
>>> Index: config/i386/i386.c
>>> ===================================================================
>>> --- config/i386/i386.c (revision 201458)
>>> +++ config/i386/i386.c (working copy)
>>> @@ -156,7 +156,7 @@ struct processor_costs ix86_size_cost =
>>> };
>>>
>>> /* Processor costs (relative to an add) */
>>> -static const
>>> +static
>>> struct processor_costs i386_cost = { /* 386 specific costs */
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -226,7 +226,7 @@ struct processor_costs i386_cost = { /*
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs i486_cost = { /* 486 specific costs */
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -298,7 +298,7 @@ struct processor_costs i486_cost = { /*
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs pentium_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -368,7 +368,7 @@ struct processor_costs pentium_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs pentiumpro_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -447,7 +447,7 @@ struct processor_costs pentiumpro_cost =
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs geode_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -518,7 +518,7 @@ struct processor_costs geode_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs k6_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (2), /* cost of a lea instruction */
>>> @@ -591,7 +591,7 @@ struct processor_costs k6_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs athlon_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (2), /* cost of a lea instruction */
>>> @@ -664,7 +664,7 @@ struct processor_costs athlon_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs k8_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (2), /* cost of a lea instruction */
>>> @@ -1265,7 +1265,7 @@ struct processor_costs btver2_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs pentium4_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (3), /* cost of a lea instruction */
>>> @@ -1336,7 +1336,7 @@ struct processor_costs pentium4_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs nocona_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1), /* cost of a lea instruction */
>>> @@ -1409,7 +1409,7 @@ struct processor_costs nocona_cost = {
>>> 1, /* cond_not_taken_branch_cost. */
>>> };
>>>
>>> -static const
>>> +static
>>> struct processor_costs atom_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1) + 1, /* cost of a lea instruction */
>>> @@ -1556,7 +1556,7 @@ struct processor_costs slm_cost = {
>>> };
>>>
>>> /* Generic64 should produce code tuned for Nocona and K8. */
>>> -static const
>>> +static
>>> struct processor_costs generic64_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> /* On all chips taken into consideration lea is 2 cycles and more. With
>>> @@ -1635,7 +1635,7 @@ struct processor_costs generic64_cost =
>>> };
>>>
>>> /* core_cost should produce code tuned for Core familly of CPUs. */
>>> -static const
>>> +static
>>> struct processor_costs core_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> /* On all chips taken into consideration lea is 2 cycles and more. With
>>> @@ -1717,7 +1717,7 @@ struct processor_costs core_cost = {
>>>
>>> /* Generic32 should produce code tuned for PPro, Pentium4, Nocona,
>>> Athlon and K8. */
>>> -static const
>>> +static
>>> struct processor_costs generic32_cost = {
>>> COSTS_N_INSNS (1), /* cost of an add instruction */
>>> COSTS_N_INSNS (1) + 1, /* cost of a lea instruction */
>>> @@ -2900,6 +2900,150 @@ ix86_debug_options (void)
>>>
>>> return;
>>> }
>>> +
>>> +static const char *stringop_alg_names[] = {
>>> +#define DEF_ENUM
>>> +#define DEF_ALG(alg, name) #name,
>>> +#include "stringop.def"
>>> +#undef DEF_ENUM
>>> +#undef DEF_ALG
>>> +};
>>> +
>>> +/* Parse parameter string passed to -mmemcpy-strategy= or -mmemset-strategy=.
>>> + The string is of the following form (or comma separated list of it):
>>> +
>>> + strategy_alg:max_size:[align|noalign]
>>> +
>>> + where the full size range for the strategy is either [0, max_size] or
>>> + [min_size, max_size], in which min_size is the max_size + 1 of the
>>> + preceding range. The last size range must have max_size == -1.
>>> +
>>> + Examples:
>>> +
>>> + 1.
>>> + -mmemcpy-strategy=libcall:-1:noalign
>>> +
>>> + this is equivalent to (for known size memcpy) -mstringop-strategy=libcall
>>> +
>>> +
>>> + 2.
>>> + -mmemset-strategy=rep_8byte:16:noalign,vector_loop:2048:align,libcall:-1:noalign
>>> +
>>> + This is to tell the compiler to use the following strategy for memset
>>> + 1) when the expected size is between [1, 16], use rep_8byte strategy;
>>> + 2) when the size is between [17, 2048], use vector_loop;
>>> + 3) when the size is > 2048, use libcall.
>>> +
>>> +*/
>>> +
>>> +struct stringop_size_range
>>> +{
>>> + int min;
>>> + int max;
>>> + stringop_alg alg;
>>> + bool noalign;
>>> +};
>>> +
>>> +static void
>>> +ix86_parse_stringop_strategy_string (char *strategy_str, bool is_memset)
>>> +{
>>> + const struct stringop_algs *default_algs;
>>> + stringop_size_range input_ranges[MAX_STRINGOP_ALGS];
>>> + char *curr_range_str, *next_range_str;
>>> + int i = 0, n = 0;
>>> +
>>> + if (is_memset)
>>> + default_algs = &ix86_cost->memset[TARGET_64BIT != 0];
>>> + else
>>> + default_algs = &ix86_cost->memcpy[TARGET_64BIT != 0];
>>> +
>>> + curr_range_str = strategy_str;
>>> +
>>> + do {
>>> +
>>> + int mins, maxs;
>>> + stringop_alg alg;
>>> + char alg_name[128];
>>> + char align[16];
>>> +
>>> + next_range_str = strchr (curr_range_str, ',');
>>> + if (next_range_str)
>>> + *next_range_str++ = '\0';
>>> +
>>> + if (3 != sscanf (curr_range_str, "%[^:]:%d:%s", alg_name, &maxs, align))
>>> + {
>>> + warning (0, "Wrong arg %s to option %s", curr_range_str,
>>> + is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> +
>>> + if (n > 0 && (maxs < (mins = input_ranges[n - 1].max + 1) && maxs != -1))
>>> + {
>>> + warning (0, "Size ranges of option %s should be increasing",
>>> + is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> +
>>> + for (i = 0; i < last_alg; i++)
>>> + {
>>> + if (!strcmp (alg_name, stringop_alg_names[i]))
>>> + {
>>> + alg = (stringop_alg) i;
>>> + break;
>>> + }
>>> + }
>>> +
>>> + if (i == last_alg)
>>> + {
>>> + warning (0, "Wrong stringop strategy name %s specified for option %s",
>>> + alg_name,
>>> + is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> +
>>> + input_ranges[n].min = mins;
>>> + input_ranges[n].max = maxs;
>>> + input_ranges[n].alg = alg;
>>> + if (!strcmp (align, "align"))
>>> + input_ranges[n].noalign = false;
>>> + else if (!strcmp (align, "noalign"))
>>> + input_ranges[n].noalign = true;
>>> + else
>>> + {
>>> + warning (0, "Unknown alignment %s specified for option %s",
>>> + align, is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> + n++;
>>> + curr_range_str = next_range_str;
>>> + } while (curr_range_str);
>>> +
>>> + if (input_ranges[n - 1].max != -1)
>>> + {
>>> + warning (0, "The max value for the last size range should be -1"
>>> + " for option %s",
>>> + is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> +
>>> + if (n > MAX_STRINGOP_ALGS)
>>> + {
>>> + warning (0, "Too many size ranges specified in option %s",
>>> + is_memset ? "-mmemset_strategy=" : "-mmemcpy_strategy=");
>>> + return;
>>> + }
>>> +
>>> + /* Now override the default algs array */
>>> + for (i = 0; i < n; i++)
>>> + {
>>> + *const_cast<int *>(&default_algs->size[i].max) = input_ranges[i].max;
>>> + *const_cast<stringop_alg *>(&default_algs->size[i].alg)
>>> + = input_ranges[i].alg;
>>> + *const_cast<int *>(&default_algs->size[i].noalign)
>>> + = input_ranges[i].noalign;
>>> + }
>>> +}
>>> +
>>>
>>> /* Override various settings based on options. If MAIN_ARGS_P, the
>>> options are from the command line, otherwise they are from
>>> @@ -4021,6 +4165,21 @@ ix86_option_override_internal (bool main
>>> /* Handle stack protector */
>>> if (!global_options_set.x_ix86_stack_protector_guard)
>>> ix86_stack_protector_guard = TARGET_HAS_BIONIC ? SSP_GLOBAL : SSP_TLS;
>>> +
>>> + /* Handle -mmemcpy-strategy= and -mmemset-strategy= */
>>> + if (ix86_tune_memcpy_strategy)
>>> + {
>>> + char *str = xstrdup (ix86_tune_memcpy_strategy);
>>> + ix86_parse_stringop_strategy_string (str, false);
>>> + free (str);
>>> + }
>>> +
>>> + if (ix86_tune_memset_strategy)
>>> + {
>>> + char *str = xstrdup (ix86_tune_memset_strategy);
>>> + ix86_parse_stringop_strategy_string (str, true);
>>> + free (str);
>>> + }
>>> }
>>>
>>> /* Implement the TARGET_OPTION_OVERRIDE hook. */
>>> @@ -22903,6 +23062,7 @@ ix86_expand_movmem (rtx dst, rtx src, rt
>>> {
>>> case libcall:
>>> case no_stringop:
>>> + case last_alg:
>>> gcc_unreachable ();
>>> case loop_1_byte:
>>> need_zero_guard = true;
>>> @@ -23093,6 +23253,7 @@ ix86_expand_movmem (rtx dst, rtx src, rt
>>> {
>>> case libcall:
>>> case no_stringop:
>>> + case last_alg:
>>> gcc_unreachable ();
>>> case loop_1_byte:
>>> case loop:
>>> @@ -23304,6 +23465,7 @@ ix86_expand_setmem (rtx dst, rtx count_e
>>> {
>>> case libcall:
>>> case no_stringop:
>>> + case last_alg:
>>> gcc_unreachable ();
>>> case loop:
>>> need_zero_guard = true;
>>> @@ -23481,6 +23643,7 @@ ix86_expand_setmem (rtx dst, rtx count_e
>>> {
>>> case libcall:
>>> case no_stringop:
>>> + case last_alg:
>>> gcc_unreachable ();
>>> case loop_1_byte:
>>> case loop:
>>> Index: config/i386/i386-opts.h
>>> ===================================================================
>>> --- config/i386/i386-opts.h (revision 201458)
>>> +++ config/i386/i386-opts.h (working copy)
>>> @@ -28,15 +28,17 @@ see the files COPYING3 and COPYING.RUNTI
>>> /* Algorithm to expand string function with. */
>>> enum stringop_alg
>>> {
>>> - no_stringop,
>>> - libcall,
>>> - rep_prefix_1_byte,
>>> - rep_prefix_4_byte,
>>> - rep_prefix_8_byte,
>>> - loop_1_byte,
>>> - loop,
>>> - unrolled_loop,
>>> - vector_loop
>>> +#undef DEF_ENUM
>>> +#define DEF_ENUM
>>> +
>>> +#undef DEF_ALG
>>> +#define DEF_ALG(alg, name) alg,
>>> +
>>> +#include "stringop.def"
>>> +last_alg
>>> +
>>> +#undef DEF_ENUM
>>> +#undef DEF_ALG
>>> };
>>>
>>> /* Available call abi. */
>>> Index: doc/invoke.texi
>>> ===================================================================
>>> --- doc/invoke.texi (revision 201458)
>>> +++ doc/invoke.texi (working copy)
>>> @@ -649,6 +649,7 @@ Objective-C and Objective-C++ Dialects}.
>>> -mbmi2 -mrtm -mlwp -mthreads @gol
>>> -mno-align-stringops -minline-all-stringops @gol
>>> -minline-stringops-dynamically -mstringop-strategy=@var{alg} @gol
>>> +-mmemcpy-strategy=@var{strategy} -mmemset-strategy=@var{strategy}
>>> -mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol
>>> -m96bit-long-double -mlong-double-64 -mlong-double-80 @gol
>>> -mregparm=@var{num} -msseregparm @gol
>>> @@ -14598,6 +14599,24 @@ Expand into an inline loop.
>>> Always use a library call.
>>> @end table
>>>
>>> +@item -mmemcpy-strategy=@var{strategy}
>>> +@opindex mmemcpy-strategy=@var{strategy}
>>> +Override the internal decision heuristic to decide if @code{__builtin_memcpy}
>>> +should be inlined and what inline algorithm to use when the expected size
>>> +of the copy operation is known. @var{strategy}
>>> +is a comma-separated list of @var{alg}:@var{max_size}:@var{dest_align} triplets.
>>> +@var{alg} is specified in @option{-mstringop-strategy}, @var{max_size} specifies
>>> +the max byte size with which inline algorithm @var{alg} is allowed. For the last
>>> +triplet, the @var{max_size} must be @code{-1}. The @var{max_size} of the triplets
>>> +in the list must be specified in increasing order. The minimal byte size for
>>> +@var{alg} is @code{0} for the first triplet and @code{@var{max_size} + 1} of the
>>> +preceding range.
>>> +
>>> +@item -mmemset-strategy=@var{strategy}
>>> +@opindex mmemset-strategy=@var{strategy}
>>> +The option is similar to @option{-mmemcpy-strategy=} except that it is to control
>>> +@code{__builtin_memset} expansion.
>>> +
>>> @item -momit-leaf-frame-pointer
>>> @opindex momit-leaf-frame-pointer
>>> Don't keep the frame pointer in a register for leaf functions. This
>>> Index: testsuite/gcc.target/i386/memcpy-strategy-1.c
>>> ===================================================================
>>> --- testsuite/gcc.target/i386/memcpy-strategy-1.c (revision 0)
>>> +++ testsuite/gcc.target/i386/memcpy-strategy-1.c (revision 0)
>>> @@ -0,0 +1,12 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-O2 -march=atom -mmemcpy-strategy=vector_loop:-1:align" } */
>>> +/* { dg-final { scan-assembler-times "movdqa" 8 { target { ! { ia32 } } } } } */
>>> +/* { dg-final { scan-assembler-times "movdqa" 4 { target { ia32 } } } } */
>>> +
>>> +char a[2048];
>>> +char b[2048];
>>> +void t (void)
>>> +{
>>> + __builtin_memcpy (a, b, 2048);
>>> +}
>>> +
>>> Index: testsuite/gcc.target/i386/memcpy-strategy-2.c
>>> ===================================================================
>>> --- testsuite/gcc.target/i386/memcpy-strategy-2.c (revision 0)
>>> +++ testsuite/gcc.target/i386/memcpy-strategy-2.c (revision 0)
>>> @@ -0,0 +1,12 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-O2 -march=atom -mmemcpy-strategy=vector_loop:3000:align,libcall:-1:align" } */
>>> +/* { dg-final { scan-assembler-times "movdqa" 8 { target { ! { ia32 } } } } } */
>>> +/* { dg-final { scan-assembler-times "movdqa" 4 { target { ia32 } } } } */
>>> +
>>> +char a[2048];
>>> +char b[2048];
>>> +void t (void)
>>> +{
>>> + __builtin_memcpy (a, b, 2048);
>>> +}
>>> +
>>> Index: testsuite/gcc.target/i386/memset-strategy-1.c
>>> ===================================================================
>>> --- testsuite/gcc.target/i386/memset-strategy-1.c (revision 0)
>>> +++ testsuite/gcc.target/i386/memset-strategy-1.c (revision 0)
>>> @@ -0,0 +1,10 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-O2 -march=atom -mmemset-strategy=libcall:-1:align" } */
>>> +/* { dg-final { scan-assembler-times "memset" 2 } } */
>>> +
>>> +char a[2048];
>>> +void t (void)
>>> +{
>>> + __builtin_memset (a, 1, 2048);
>>> +}
>>> +
>>> Index: testsuite/gcc.target/i386/memcpy-strategy-3.c
>>> ===================================================================
>>> --- testsuite/gcc.target/i386/memcpy-strategy-3.c (revision 0)
>>> +++ testsuite/gcc.target/i386/memcpy-strategy-3.c (revision 0)
>>> @@ -0,0 +1,11 @@
>>> +/* { dg-do compile } */
>>> +/* { dg-options "-O2 -march=atom -mmemcpy-strategy=vector_loop:2000:align,libcall:-1:align" } */
>>> +/* { dg-final { scan-assembler-times "memcpy" 2 } } */
>>> +
>>> +char a[2048];
>>> +char b[2048];
>>> +void t (void)
>>> +{
>>> + __builtin_memcpy (a, b, 2048);
>>> +}
>>> +
>>
--
---
Best regards,
Michael V. Zolotukhin,
Software Engineer
Intel Corporation.