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 <davi...@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 <davi...@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 <davi...@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 <davi...@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);
+}
+
