Patchwork -mtune-ctrl=.... support, round-2

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Submitter Xinliang David Li
Date Aug. 12, 2013, 4:54 p.m.
Message ID <CAAkRFZ+b5eWfWTCnFD5oWfy8yfbDOryU5tUjRe=bEJ6WmUeJtw@mail.gmail.com>
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Permalink /patch/266577/
State New
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Xinliang David Li - Aug. 12, 2013, 4:54 p.m.
Fixed some formatting issues and typos. There are no regressions with
the attached patch. Ok for trunk?

thanks,

David

On Wed, Aug 7, 2013 at 10:12 PM, Xinliang David Li <davidxl@google.com> wrote:
> Hi, the attached is a follow up patch. The patch includes the following changes:
>
> 1. new option -mno-default -- suggested by H.J. It can be combined
> with -mtune-ctrl= to clear the default settings.
> 2. new option -mdump-tune-features -- this option can be used to dump
> all feature names and their default settings.
> 3. Added documentation to the 3 new options
>
> 4. Move the contents of inital_x86_tune_features into x86-tune.def to
> make sure they are always in sync
> 5. Some refactoring and handle the the tune features properly during
> target option restore.
>
> 2013-08-07  Xinliang David Li  <davidxl@google.com>
>
>         * config/i386/i386.h: Adjust macro definition.
>         * config/i386/i386.opt: Define two new options.
>         * config/i386/x86-tune.def: Add arch selector field in macros.
>         * config/i386/i386.h: include x86-tune.def.
>         * config/i386/i386.c (ix86_option_override_internal):
>         Refactor the code.
>         (parse_mtune_ctrl_str): New function.
>         (set_ix86_tune_features): New function.
>         (ix86_function_specific_restore): Call the new helper function.
>
> Ok for trunk after testing?
>
> thanks,
>
> David
>
>
> On Wed, Aug 7, 2013 at 5:22 PM, Xinliang David Li <davidxl@google.com> wrote:
>> On Wed, Aug 7, 2013 at 4:54 PM, Joseph S. Myers <joseph@codesourcery.com> wrote:
>>> On Sun, 4 Aug 2013, Andi Kleen wrote:
>>>
>>>> Richard Biener <richard.guenther@gmail.com> writes:
>>>> >
>>>> > The patch fails to add documentation.
>>>>
>>>> That seems like a feature, it's likely not useful for the general
>>>> public. More for specialized tools that automatically search
>>>> for the best tuning.
>>>
>>> If such a tool is not part of GCC itself, then it is a user of GCC and
>>> documentation should be provided for those writing such a tool.
>>>
>>> Options should be undocumented in very limited cases such as multiple
>>> variant spellings where only one should be used but others are accepted
>>> because they were historically, or whether the user interface to an option
>>> is separate from the internal option passed to cc1 (the documentation is
>>> of options as passed to the driver, but the .opt file may describe options
>>> passed to cc1 as a result of other options being passed to the driver), or
>>> the option really is only for use within the build of GCC itself.
>>> Otherwise, the strong presumption is that all options should be
>>> documented, with appropriate caveats as applicable about the cases where
>>> an option is useful.
>>>
>>
>> Fair enough. I will add the documentation in a followup patch which
>> also implements H.J's proposal -mno-default and cleans up the initial
>> tuning array to be always in sync with new enums.
>>
>>
>>>> > And I am nervous about testing
>>>> > coverage - is this considered a development option only or are random
>>>> > combinations expected to work in all situations? I expect not, thus
>>>> > this looks like a dangerous option?
>>>>
>>>> When it's undocumented it doesn't need to work in every situation?
>>>
>>> No input files and command-line arguments whatsoever to the driver should
>>> result in ICEs, including undocumented options.
>>
>> True -- if ICEs are found, we should fix them.
>>
>> thanks,
>>
>> David
>>
>>>
>>> --
>>> Joseph S. Myers
>>> joseph@codesourcery.com
Xinliang David Li - Aug. 14, 2013, 3:40 p.m.
Ping?

David

On Mon, Aug 12, 2013 at 9:54 AM, Xinliang David Li <davidxl@google.com> wrote:
> Fixed some formatting issues and typos. There are no regressions with
> the attached patch. Ok for trunk?
>
> thanks,
>
> David
>
> On Wed, Aug 7, 2013 at 10:12 PM, Xinliang David Li <davidxl@google.com> wrote:
>> Hi, the attached is a follow up patch. The patch includes the following changes:
>>
>> 1. new option -mno-default -- suggested by H.J. It can be combined
>> with -mtune-ctrl= to clear the default settings.
>> 2. new option -mdump-tune-features -- this option can be used to dump
>> all feature names and their default settings.
>> 3. Added documentation to the 3 new options
>>
>> 4. Move the contents of inital_x86_tune_features into x86-tune.def to
>> make sure they are always in sync
>> 5. Some refactoring and handle the the tune features properly during
>> target option restore.
>>
>> 2013-08-07  Xinliang David Li  <davidxl@google.com>
>>
>>         * config/i386/i386.h: Adjust macro definition.
>>         * config/i386/i386.opt: Define two new options.
>>         * config/i386/x86-tune.def: Add arch selector field in macros.
>>         * config/i386/i386.h: include x86-tune.def.
>>         * config/i386/i386.c (ix86_option_override_internal):
>>         Refactor the code.
>>         (parse_mtune_ctrl_str): New function.
>>         (set_ix86_tune_features): New function.
>>         (ix86_function_specific_restore): Call the new helper function.
>>
>> Ok for trunk after testing?
>>
>> thanks,
>>
>> David
>>
>>
>> On Wed, Aug 7, 2013 at 5:22 PM, Xinliang David Li <davidxl@google.com> wrote:
>>> On Wed, Aug 7, 2013 at 4:54 PM, Joseph S. Myers <joseph@codesourcery.com> wrote:
>>>> On Sun, 4 Aug 2013, Andi Kleen wrote:
>>>>
>>>>> Richard Biener <richard.guenther@gmail.com> writes:
>>>>> >
>>>>> > The patch fails to add documentation.
>>>>>
>>>>> That seems like a feature, it's likely not useful for the general
>>>>> public. More for specialized tools that automatically search
>>>>> for the best tuning.
>>>>
>>>> If such a tool is not part of GCC itself, then it is a user of GCC and
>>>> documentation should be provided for those writing such a tool.
>>>>
>>>> Options should be undocumented in very limited cases such as multiple
>>>> variant spellings where only one should be used but others are accepted
>>>> because they were historically, or whether the user interface to an option
>>>> is separate from the internal option passed to cc1 (the documentation is
>>>> of options as passed to the driver, but the .opt file may describe options
>>>> passed to cc1 as a result of other options being passed to the driver), or
>>>> the option really is only for use within the build of GCC itself.
>>>> Otherwise, the strong presumption is that all options should be
>>>> documented, with appropriate caveats as applicable about the cases where
>>>> an option is useful.
>>>>
>>>
>>> Fair enough. I will add the documentation in a followup patch which
>>> also implements H.J's proposal -mno-default and cleans up the initial
>>> tuning array to be always in sync with new enums.
>>>
>>>
>>>>> > And I am nervous about testing
>>>>> > coverage - is this considered a development option only or are random
>>>>> > combinations expected to work in all situations? I expect not, thus
>>>>> > this looks like a dangerous option?
>>>>>
>>>>> When it's undocumented it doesn't need to work in every situation?
>>>>
>>>> No input files and command-line arguments whatsoever to the driver should
>>>> result in ICEs, including undocumented options.
>>>
>>> True -- if ICEs are found, we should fix them.
>>>
>>> thanks,
>>>
>>> David
>>>
>>>>
>>>> --
>>>> Joseph S. Myers
>>>> joseph@codesourcery.com
Jan Hubicka - Aug. 14, 2013, 4:01 p.m.
> > 2013-08-07  Xinliang David Li  <davidxl@google.com>
> >
> >         * config/i386/i386.h: Adjust macro definition.
> >         * config/i386/i386.opt: Define two new options.
> >         * config/i386/x86-tune.def: Add arch selector field in macros.
> >         * config/i386/i386.h: include x86-tune.def.
> >         * config/i386/i386.c (ix86_option_override_internal):
> >         Refactor the code.
> >         (parse_mtune_ctrl_str): New function.
> >         (set_ix86_tune_features): New function.
> >         (ix86_function_specific_restore): Call the new helper function.
OK.
> +/* Helper function to set ix86_tune_features. IX86_TUNE is the
> +   processor type.  */
> +
> +static void
> +set_ix86_tune_features (enum processor_type ix86_tune, bool dump)
> +{
> +  unsigned int ix86_tune_mask = 1u << ix86_tune;
> +  int i;
> +
> +  for (i = 0; i < X86_TUNE_LAST; ++i)
> +    {
> +      if (ix86_tune_no_default)
> +        ix86_tune_features[i] = 0;
> +      else
> +        ix86_tune_features[i] = !!(initial_ix86_tune_features[i] & ix86_tune_mask);
Perhaps != 0?
> Index: doc/invoke.texi
> ===================================================================
> --- doc/invoke.texi	(revision 201645)
> +++ doc/invoke.texi	(working copy)
> @@ -637,6 +637,7 @@ Objective-C and Objective-C++ Dialects}.
>  
>  @emph{i386 and x86-64 Options}
>  @gccoptlist{-mtune=@var{cpu-type}  -march=@var{cpu-type} @gol
> +-mtune-ctrl=@var{feature-list} -mdump-tune-features -mno-default @gol
>  -mfpmath=@var{unit} @gol
>  -masm=@var{dialect}  -mno-fancy-math-387 @gol
>  -mno-fp-ret-in-387  -msoft-float @gol
> @@ -14429,6 +14430,24 @@ supported architecture, using the approp
>  the file containing the CPU detection code should be compiled without
>  these options.
>  
> +@item -mdump-tune-features
> +@opindex mdump-tune-features
> +This option instructs GCC to dump the names of the x86 performance 
> +tuning features and default settings. The names can be used in 
> +@option{-mtune-ctrl=@var{feature-list}}.
> +
> +@item -mtune-ctrl=@var{feature-list}
> +@opindex mtune-ctrl=@var{feature-list}
> +This option is used to do fine grain control of x86 code generation features.
> +@var{feature-list} is a comma separated list of @var{feature} names. See also
> +@option{-mdump-tune-features}. When specified, the @var{feature} will be turned
> +on if it is not preceded with @code{^}, otherwise, it will be turned off.
> +
> +@item -mno-default
> +@opindex mno-default
> +This option instructs GCC to turn off all tunable features. See also 
> +@option{-mtune-ctrl=@var{feature-list}} and @option{-mdump-tune-features}.

Perhaps we shall at least explicitely document that this is intended for devleopment
only and may lead to ICEs.

Honza
> +
>  @item -mcld
>  @opindex mcld
>  This option instructs GCC to emit a @code{cld} instruction in the prologue
Xinliang David Li - Aug. 14, 2013, 4:14 p.m.
On Wed, Aug 14, 2013 at 9:01 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> > 2013-08-07  Xinliang David Li  <davidxl@google.com>
>> >
>> >         * config/i386/i386.h: Adjust macro definition.
>> >         * config/i386/i386.opt: Define two new options.
>> >         * config/i386/x86-tune.def: Add arch selector field in macros.
>> >         * config/i386/i386.h: include x86-tune.def.
>> >         * config/i386/i386.c (ix86_option_override_internal):
>> >         Refactor the code.
>> >         (parse_mtune_ctrl_str): New function.
>> >         (set_ix86_tune_features): New function.
>> >         (ix86_function_specific_restore): Call the new helper function.
> OK.
>> +/* Helper function to set ix86_tune_features. IX86_TUNE is the
>> +   processor type.  */
>> +
>> +static void
>> +set_ix86_tune_features (enum processor_type ix86_tune, bool dump)
>> +{
>> +  unsigned int ix86_tune_mask = 1u << ix86_tune;
>> +  int i;
>> +
>> +  for (i = 0; i < X86_TUNE_LAST; ++i)
>> +    {
>> +      if (ix86_tune_no_default)
>> +        ix86_tune_features[i] = 0;
>> +      else
>> +        ix86_tune_features[i] = !!(initial_ix86_tune_features[i] & ix86_tune_mask);
> Perhaps != 0?

This part is copied from the original version -- so I will leave it
alone here ;)

>> Index: doc/invoke.texi
>> ===================================================================
>> --- doc/invoke.texi   (revision 201645)
>> +++ doc/invoke.texi   (working copy)
>> @@ -637,6 +637,7 @@ Objective-C and Objective-C++ Dialects}.
>>
>>  @emph{i386 and x86-64 Options}
>>  @gccoptlist{-mtune=@var{cpu-type}  -march=@var{cpu-type} @gol
>> +-mtune-ctrl=@var{feature-list} -mdump-tune-features -mno-default @gol
>>  -mfpmath=@var{unit} @gol
>>  -masm=@var{dialect}  -mno-fancy-math-387 @gol
>>  -mno-fp-ret-in-387  -msoft-float @gol
>> @@ -14429,6 +14430,24 @@ supported architecture, using the approp
>>  the file containing the CPU detection code should be compiled without
>>  these options.
>>
>> +@item -mdump-tune-features
>> +@opindex mdump-tune-features
>> +This option instructs GCC to dump the names of the x86 performance
>> +tuning features and default settings. The names can be used in
>> +@option{-mtune-ctrl=@var{feature-list}}.
>> +
>> +@item -mtune-ctrl=@var{feature-list}
>> +@opindex mtune-ctrl=@var{feature-list}
>> +This option is used to do fine grain control of x86 code generation features.
>> +@var{feature-list} is a comma separated list of @var{feature} names. See also
>> +@option{-mdump-tune-features}. When specified, the @var{feature} will be turned
>> +on if it is not preceded with @code{^}, otherwise, it will be turned off.
>> +
>> +@item -mno-default
>> +@opindex mno-default
>> +This option instructs GCC to turn off all tunable features. See also
>> +@option{-mtune-ctrl=@var{feature-list}} and @option{-mdump-tune-features}.
>
> Perhaps we shall at least explicitely document that this is intended for devleopment
> only and may lead to ICEs.

Ok will do.

thanks,

David

>
> Honza
>> +
>>  @item -mcld
>>  @opindex mcld
>>  This option instructs GCC to emit a @code{cld} instruction in the prologue
>

Patch

Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c	(revision 201645)
+++ config/i386/i386.c	(working copy)
@@ -1938,7 +1938,7 @@  const struct processor_costs *ix86_cost
 
 const char* ix86_tune_feature_names[X86_TUNE_LAST] = {
 #undef DEF_TUNE
-#define DEF_TUNE(tune, name) name,
+#define DEF_TUNE(tune, name, selector) name,
 #include "x86-tune.def"
 #undef DEF_TUNE
 };
@@ -1949,281 +1949,10 @@  unsigned char ix86_tune_features[X86_TUN
 /* Feature tests against the various tunings used to create ix86_tune_features
    based on the processor mask.  */
 static unsigned int initial_ix86_tune_features[X86_TUNE_LAST] = {
-  /* X86_TUNE_USE_LEAVE: Leave does not affect Nocona SPEC2000 results
-     negatively, so enabling for Generic64 seems like good code size
-     tradeoff.  We can't enable it for 32bit generic because it does not
-     work well with PPro base chips.  */
-  m_386 | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC64,
-
-  /* X86_TUNE_PUSH_MEMORY */
-  m_386 | m_P4_NOCONA | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_ZERO_EXTEND_WITH_AND */
-  m_486 | m_PENT,
-
-  /* X86_TUNE_UNROLL_STRLEN */
-  m_486 | m_PENT | m_PPRO | m_ATOM | m_SLM | m_CORE_ALL | m_K6 | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* 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.  */
-  0,
-
-  /* X86_TUNE_DOUBLE_WITH_ADD */
-  ~m_386,
-
-  /* X86_TUNE_USE_SAHF */
-  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC,
-
-  /* X86_TUNE_MOVX: Enable to zero extend integer registers to avoid
-     partial dependencies.  */
-  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_GEODE | m_AMD_MULTIPLE  | m_GENERIC,
-
-  /* X86_TUNE_PARTIAL_REG_STALL: We probably ought to watch for partial
-     register stalls on Generic32 compilation setting as well.  However
-     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.  Because this option
-     pays back little on PPro based chips and is in conflict with partial reg
-     dependencies used by Athlon/P4 based chips, it is better to leave it off
-     for generic32 for now.  */
-  m_PPRO,
-
-  /* X86_TUNE_PARTIAL_FLAG_REG_STALL */
-  m_CORE_ALL | m_GENERIC,
-
-  /* X86_TUNE_LCP_STALL: Avoid an expensive length-changing prefix stall
-   * on 16-bit immediate moves into memory on Core2 and Corei7.  */
-  m_CORE_ALL | m_GENERIC,
-
-  /* X86_TUNE_USE_HIMODE_FIOP */
-  m_386 | m_486 | m_K6_GEODE,
-
-  /* X86_TUNE_USE_SIMODE_FIOP */
-  ~(m_PENT | m_PPRO | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC),
-
-  /* X86_TUNE_USE_MOV0 */
-  m_K6,
-
-  /* X86_TUNE_USE_CLTD */
-  ~(m_PENT | m_ATOM | m_SLM | m_K6),
-
-  /* X86_TUNE_USE_XCHGB: Use xchgb %rh,%rl instead of rolw/rorw $8,rx.  */
-  m_PENT4,
-
-  /* X86_TUNE_SPLIT_LONG_MOVES */
-  m_PPRO,
-
-  /* X86_TUNE_READ_MODIFY_WRITE */
-  ~m_PENT,
-
-  /* X86_TUNE_READ_MODIFY */
-  ~(m_PENT | m_PPRO),
-
-  /* X86_TUNE_PROMOTE_QIMODE */
-  m_386 | m_486 | m_PENT | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_FAST_PREFIX */
-  ~(m_386 | m_486 | m_PENT),
-
-  /* X86_TUNE_SINGLE_STRINGOP */
-  m_386 | m_P4_NOCONA,
-
-  /* X86_TUNE_QIMODE_MATH */
-  ~0,
-
-  /* X86_TUNE_HIMODE_MATH: On PPro this flag is meant to avoid partial
-     register stalls.  Just like X86_TUNE_PARTIAL_REG_STALL this option
-     might be considered for Generic32 if our scheme for avoiding partial
-     stalls was more effective.  */
-  ~m_PPRO,
-
-  /* X86_TUNE_PROMOTE_QI_REGS */
-  0,
-
-  /* X86_TUNE_PROMOTE_HI_REGS */
-  m_PPRO,
-
-  /* X86_TUNE_SINGLE_POP: Enable if single pop insn is preferred
-     over esp addition.  */
-  m_386 | m_486 | m_PENT | m_PPRO,
-
-  /* X86_TUNE_DOUBLE_POP: Enable if double pop insn is preferred
-     over esp addition.  */
-  m_PENT,
-
-  /* X86_TUNE_SINGLE_PUSH: Enable if single push insn is preferred
-     over esp subtraction.  */
-  m_386 | m_486 | m_PENT | m_K6_GEODE,
-
-  /* X86_TUNE_DOUBLE_PUSH. Enable if double push insn is preferred
-     over esp subtraction.  */
-  m_PENT | m_K6_GEODE,
-
-  /* X86_TUNE_INTEGER_DFMODE_MOVES: Enable if integer moves are preferred
-     for DFmode copies */
-  ~(m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_GEODE | m_AMD_MULTIPLE | m_GENERIC),
-
-  /* X86_TUNE_PARTIAL_REG_DEPENDENCY */
-  m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY: In the Generic model we have a
-     conflict here in between PPro/Pentium4 based chips that thread 128bit
-     SSE registers as single units versus K8 based chips that divide SSE
-     registers to two 64bit halves.  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.  */
-  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMDFAM10 | m_BDVER | m_GENERIC,
-
-  /* X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL */
-  m_COREI7 | m_AMDFAM10 | m_BDVER | m_BTVER | m_SLM,
-
-  /* X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL */
-  m_COREI7 | m_BDVER | m_SLM,
-
-  /* X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL */
-  m_BDVER ,
-
-  /* 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.  */
-  m_ATHLON_K8,
-
-  /* X86_TUNE_SSE_TYPELESS_STORES */
-  m_AMD_MULTIPLE,
-
-  /* X86_TUNE_SSE_LOAD0_BY_PXOR */
-  m_PPRO | m_P4_NOCONA,
-
-  /* X86_TUNE_MEMORY_MISMATCH_STALL */
-  m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_PROLOGUE_USING_MOVE */
-  m_PPRO | m_ATHLON_K8,
-
-  /* X86_TUNE_EPILOGUE_USING_MOVE */
-  m_PPRO | m_ATHLON_K8,
-
-  /* X86_TUNE_SHIFT1 */
-  ~m_486,
-
-  /* X86_TUNE_USE_FFREEP */
-  m_AMD_MULTIPLE,
-
-  /* X86_TUNE_INTER_UNIT_MOVES_TO_VEC */
-  ~(m_AMD_MULTIPLE | m_GENERIC),
-
-  /* X86_TUNE_INTER_UNIT_MOVES_FROM_VEC */
-  ~m_ATHLON_K8,
-
-  /* X86_TUNE_INTER_UNIT_CONVERSIONS */
-  ~(m_AMDFAM10 | m_BDVER ),
-
-  /* X86_TUNE_FOUR_JUMP_LIMIT: Some CPU cores are not able to predict more
-     than 4 branch instructions in the 16 byte window.  */
-  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_SCHEDULE */
-  m_PENT | m_PPRO | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_USE_BT */
-  m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_USE_INCDEC */
-  ~(m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_GENERIC),
-
-  /* X86_TUNE_PAD_RETURNS */
-  m_CORE_ALL | m_AMD_MULTIPLE | m_GENERIC,
-
-  /* X86_TUNE_PAD_SHORT_FUNCTION: Pad short function.  */
-  m_ATOM,
-
-  /* X86_TUNE_EXT_80387_CONSTANTS */
-  m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE | m_ATHLON_K8 | m_GENERIC,
-
-  /* X86_TUNE_AVOID_VECTOR_DECODE */
-  m_CORE_ALL | m_K8 | m_GENERIC64,
-
-  /* X86_TUNE_PROMOTE_HIMODE_IMUL: Modern CPUs have same latency for HImode
-     and SImode multiply, but 386 and 486 do HImode multiply faster.  */
-  ~(m_386 | m_486),
-
-  /* X86_TUNE_SLOW_IMUL_IMM32_MEM: Imul of 32-bit constant and memory is
-     vector path on AMD machines.  */
-  m_CORE_ALL | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64,
-
-  /* X86_TUNE_SLOW_IMUL_IMM8: Imul of 8-bit constant is vector path on AMD
-     machines.  */
-  m_CORE_ALL | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64,
-
-  /* X86_TUNE_MOVE_M1_VIA_OR: On pentiums, it is faster to load -1 via OR
-     than a MOV.  */
-  m_PENT,
-
-  /* X86_TUNE_NOT_UNPAIRABLE: NOT is not pairable on Pentium, while XOR is,
-     but one byte longer.  */
-  m_PENT,
-
-  /* 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.  */
-  m_K6,
-
-  /* X86_TUNE_USE_VECTOR_FP_CONVERTS: Prefer vector packed SSE conversion
-     from FP to FP. */
-  m_CORE_ALL | m_AMDFAM10 | m_GENERIC,
-
-  /* X86_TUNE_USE_VECTOR_CONVERTS: Prefer vector packed SSE conversion
-     from integer to FP. */
-  m_AMDFAM10,
-
-  /* X86_TUNE_FUSE_CMP_AND_BRANCH: Fuse a compare or test instruction
-     with a subsequent conditional jump instruction into a single
-     compare-and-branch uop.  */
-  m_BDVER,
-
-  /* X86_TUNE_OPT_AGU: Optimize for Address Generation Unit. This flag
-     will impact LEA instruction selection. */
-  m_ATOM | m_SLM,
-
-  /* X86_TUNE_VECTORIZE_DOUBLE: Enable double precision vector
-     instructions.  */
-  ~m_ATOM,
-
-  /* X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL: Enable software prefetching
-     at -O3.  For the moment, the prefetching seems badly tuned for Intel
-     chips.  */
-  m_K6_GEODE | m_AMD_MULTIPLE,
-
-  /* X86_TUNE_AVX128_OPTIMAL: Enable 128-bit AVX instruction generation for
-     the auto-vectorizer.  */
-  m_BDVER | m_BTVER2,
-
-  /* X86_TUNE_REASSOC_INT_TO_PARALLEL: Try to produce parallel computations
-     during reassociation of integer computation.  */
-  m_ATOM,
-
-  /* X86_TUNE_REASSOC_FP_TO_PARALLEL: Try to produce parallel computations
-     during reassociation of fp computation.  */
-  m_ATOM | m_SLM | m_HASWELL | m_BDVER1 | m_BDVER2,
-
-  /* X86_TUNE_GENERAL_REGS_SSE_SPILL: Try to spill general regs to SSE
-     regs instead of memory.  */
-  m_CORE_ALL,
-
-  /* X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE: Try to avoid memory operands for
-     a conditional move.  */
-  m_ATOM,
-
-  /* X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS: Try to split memory operand for
-     fp converts to destination register.  */
-  m_SLM
-
+#undef DEF_TUNE
+#define DEF_TUNE(tune, name, selector) selector,
+#include "x86-tune.def"
+#undef DEF_TUNE
 };
 
 /* Feature tests against the various architecture variations.  */
@@ -3171,6 +2900,80 @@  ix86_parse_stringop_strategy_string (cha
 }
 
 
+/* parse -mtune-ctrl= option. When DUMP is true,
+   print the features that are explicitly set.  */
+
+static void
+parse_mtune_ctrl_str (bool dump)
+{
+  if (!ix86_tune_ctrl_string)
+    return;
+
+  char *next_feature_string = NULL;
+  char *curr_feature_string = xstrdup (ix86_tune_ctrl_string);
+  char *orig = curr_feature_string;
+  int i;
+  do
+    {
+      bool clear = false;
+
+      next_feature_string = strchr (curr_feature_string, ',');
+      if (next_feature_string)
+        *next_feature_string++ = '\0';
+      if (*curr_feature_string == '^')
+        {
+          curr_feature_string++;
+          clear = true;
+        }
+      for (i = 0; i < X86_TUNE_LAST; i++)
+        {
+          if (!strcmp (curr_feature_string, ix86_tune_feature_names[i]))
+            {
+              ix86_tune_features[i] = !clear;
+              if (dump)
+                fprintf (stderr, "Explicitly %s feature %s\n",
+                         clear ? "clear" : "set", ix86_tune_feature_names[i]);
+              break;
+            }
+        }
+      if (i == X86_TUNE_LAST)
+        error ("Unknown parameter to option -mtune-ctrl: %s",
+               clear ? curr_feature_string - 1 : curr_feature_string);
+      curr_feature_string = next_feature_string;
+    }
+  while (curr_feature_string);
+  free (orig);
+}
+
+/* Helper function to set ix86_tune_features. IX86_TUNE is the
+   processor type.  */
+
+static void
+set_ix86_tune_features (enum processor_type ix86_tune, bool dump)
+{
+  unsigned int ix86_tune_mask = 1u << ix86_tune;
+  int i;
+
+  for (i = 0; i < X86_TUNE_LAST; ++i)
+    {
+      if (ix86_tune_no_default)
+        ix86_tune_features[i] = 0;
+      else
+        ix86_tune_features[i] = !!(initial_ix86_tune_features[i] & ix86_tune_mask);
+    }
+
+  if (dump)
+    {
+      fprintf (stderr, "List of x86 specific tuning parameter names:\n");
+      for (i = 0; i < X86_TUNE_LAST; i++)
+        fprintf (stderr, "%s : %s\n", ix86_tune_feature_names[i],
+                 ix86_tune_features[i] ? "on" : "off");
+    }
+
+  parse_mtune_ctrl_str (dump);
+}
+
+
 /* Override various settings based on options.  If MAIN_ARGS_P, the
    options are from the command line, otherwise they are from
    attributes.  */
@@ -3816,43 +3619,7 @@  ix86_option_override_internal (bool main
     error ("bad value (%s) for %stune=%s %s",
 	   ix86_tune_string, prefix, suffix, sw);
 
-  ix86_tune_mask = 1u << ix86_tune;
-  for (i = 0; i < X86_TUNE_LAST; ++i)
-    ix86_tune_features[i] = !!(initial_ix86_tune_features[i] & ix86_tune_mask);
-
-  if (ix86_tune_ctrl_string)
-    {
-      /* parse the tune ctrl string in the following form:
-         [^]tune_name1,[^]tune_name2,..a */
-      char *next_feature_string = NULL;
-      char *curr_feature_string = xstrdup (ix86_tune_ctrl_string);
-      char *orig = curr_feature_string;
-      do {
-        bool clear = false;
-
-        next_feature_string = strchr (curr_feature_string, ',');
-	if (next_feature_string)
-          *next_feature_string++ = '\0';
-        if (*curr_feature_string == '^')
-	  {
-	    curr_feature_string++;
-	    clear = true;
-	  }
-        for (i = 0; i < X86_TUNE_LAST; i++)
-	  {
-            if (!strcmp (curr_feature_string, ix86_tune_feature_names[i]))
-	      {
-                ix86_tune_features[i] = !clear;
-                break;
-              }
-	  }
-        if (i == X86_TUNE_LAST)
-	  warning (0, "Unknown parameter to option -mtune-ctrl: %s",
-	           clear ? curr_feature_string - 1 : curr_feature_string);
-	curr_feature_string = next_feature_string;    
-      } while (curr_feature_string);
-      free (orig);
-    }
+  set_ix86_tune_features (ix86_tune, ix86_dump_tunes);
 
 #ifndef USE_IX86_FRAME_POINTER
 #define USE_IX86_FRAME_POINTER 0
@@ -4088,6 +3855,7 @@  ix86_option_override_internal (bool main
 	gcc_unreachable ();
       }
 
+  ix86_tune_mask = 1u << ix86_tune;
   if ((!USE_IX86_FRAME_POINTER
        || (x86_accumulate_outgoing_args & ix86_tune_mask))
       && !(target_flags_explicit & MASK_ACCUMULATE_OUTGOING_ARGS)
@@ -4453,7 +4221,7 @@  ix86_function_specific_restore (struct c
 {
   enum processor_type old_tune = ix86_tune;
   enum processor_type old_arch = ix86_arch;
-  unsigned int ix86_arch_mask, ix86_tune_mask;
+  unsigned int ix86_arch_mask;
   int i;
 
   ix86_arch = (enum processor_type) ptr->arch;
@@ -4477,12 +4245,7 @@  ix86_function_specific_restore (struct c
 
   /* Recreate the tune optimization tests */
   if (old_tune != ix86_tune)
-    {
-      ix86_tune_mask = 1u << ix86_tune;
-      for (i = 0; i < X86_TUNE_LAST; ++i)
-	ix86_tune_features[i]
-	  = !!(initial_ix86_tune_features[i] & ix86_tune_mask);
-    }
+    set_ix86_tune_features (ix86_tune, false);
 }
 
 /* Print the current options */
Index: config/i386/i386.h
===================================================================
--- config/i386/i386.h	(revision 201645)
+++ config/i386/i386.h	(working copy)
@@ -262,7 +262,7 @@  extern const struct processor_costs ix86
 /* Feature tests against the various tunings.  */
 enum ix86_tune_indices {
 #undef DEF_TUNE
-#define DEF_TUNE(tune, name) tune,
+#define DEF_TUNE(tune, name, selector) tune,
 #include "x86-tune.def"
 #undef DEF_TUNE
 X86_TUNE_LAST
Index: config/i386/x86-tune.def
===================================================================
--- config/i386/x86-tune.def	(revision 201644)
+++ config/i386/x86-tune.def	(working copy)
@@ -1,4 +1,4 @@ 
-/* Definitions of target machine for GCC for IA-32.
+/* Definitions of x86 tunable features.
    Copyright (C) 2013 Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -13,85 +13,220 @@  but WITHOUT ANY WARRANTY; without even t
 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_TUNE (X86_TUNE_USE_LEAVE, "use_leave")
-DEF_TUNE (X86_TUNE_PUSH_MEMORY, "push_memory")
-DEF_TUNE (X86_TUNE_ZERO_EXTEND_WITH_AND, "zero_extend_with_and")
-DEF_TUNE (X86_TUNE_UNROLL_STRLEN, "unroll_strlen")
-DEF_TUNE (X86_TUNE_BRANCH_PREDICTION_HINTS, "branch_prediction_hints")
-DEF_TUNE (X86_TUNE_DOUBLE_WITH_ADD, "double_with_add")
-DEF_TUNE (X86_TUNE_USE_SAHF, "use_sahf")
-DEF_TUNE (X86_TUNE_MOVX, "movx")
-DEF_TUNE (X86_TUNE_PARTIAL_REG_STALL, "partial_reg_stall")
-DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL, "partial_flag_reg_stall")
-DEF_TUNE (X86_TUNE_LCP_STALL, "lcp_stall")
-DEF_TUNE (X86_TUNE_USE_HIMODE_FIOP, "use_himode_fiop")
-DEF_TUNE (X86_TUNE_USE_SIMODE_FIOP, "use_simode_fiop")
-DEF_TUNE (X86_TUNE_USE_MOV0, "use_mov0")
-DEF_TUNE (X86_TUNE_USE_CLTD, "use_cltd")
-DEF_TUNE (X86_TUNE_USE_XCHGB, "use_xchgb")
-DEF_TUNE (X86_TUNE_SPLIT_LONG_MOVES, "split_long_moves")
-DEF_TUNE (X86_TUNE_READ_MODIFY_WRITE, "read_modify_write")
-DEF_TUNE (X86_TUNE_READ_MODIFY, "read_modify")
-DEF_TUNE (X86_TUNE_PROMOTE_QIMODE, "promote_qimode")
-DEF_TUNE (X86_TUNE_FAST_PREFIX, "fast_prefix")
-DEF_TUNE (X86_TUNE_SINGLE_STRINGOP, "single_stringop")
-DEF_TUNE (X86_TUNE_QIMODE_MATH, "qimode_math")
-DEF_TUNE (X86_TUNE_HIMODE_MATH, "himode_math")
-DEF_TUNE (X86_TUNE_PROMOTE_QI_REGS, "promote_qi_regs")
-DEF_TUNE (X86_TUNE_PROMOTE_HI_REGS, "promote_hi_regs")
-DEF_TUNE (X86_TUNE_SINGLE_POP, "single_pop")
-DEF_TUNE (X86_TUNE_DOUBLE_POP, "double_pop")
-DEF_TUNE (X86_TUNE_SINGLE_PUSH, "single_push")
-DEF_TUNE (X86_TUNE_DOUBLE_PUSH, "double_push")
-DEF_TUNE (X86_TUNE_INTEGER_DFMODE_MOVES, "integer_dfmode_moves")
-DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency")
-DEF_TUNE (X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY, "sse_partial_reg_dependency")
-DEF_TUNE (X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL, "sse_unaligned_load_optimal")
-DEF_TUNE (X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL, "sse_unaligned_store_optimal")
-DEF_TUNE (X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL, "sse_packed_single_insn_optimal")
-DEF_TUNE (X86_TUNE_SSE_SPLIT_REGS, "sse_split_regs")
-DEF_TUNE (X86_TUNE_SSE_TYPELESS_STORES, "sse_typeless_stores")
-DEF_TUNE (X86_TUNE_SSE_LOAD0_BY_PXOR, "sse_load0_by_pxor")
-DEF_TUNE (X86_TUNE_MEMORY_MISMATCH_STALL, "memory_mismatch_stall")
-DEF_TUNE (X86_TUNE_PROLOGUE_USING_MOVE, "prologue_using_move")
-DEF_TUNE (X86_TUNE_EPILOGUE_USING_MOVE, "epilogue_using_move")
-DEF_TUNE (X86_TUNE_SHIFT1, "shift1")
-DEF_TUNE (X86_TUNE_USE_FFREEP, "use_ffreep")
-DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_TO_VEC, "inter_unit_moves_to_vec")
-DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_FROM_VEC, "inter_unit_moves_from_vec")
-DEF_TUNE (X86_TUNE_INTER_UNIT_CONVERSIONS, "inter_unit_conversions")
-DEF_TUNE (X86_TUNE_FOUR_JUMP_LIMIT, "four_jump_limit")
-DEF_TUNE (X86_TUNE_SCHEDULE, "schedule")
-DEF_TUNE (X86_TUNE_USE_BT, "use_bt")
-DEF_TUNE (X86_TUNE_USE_INCDEC, "use_incdec")
-DEF_TUNE (X86_TUNE_PAD_RETURNS, "pad_returns")
-DEF_TUNE (X86_TUNE_PAD_SHORT_FUNCTION, "pad_short_function")
-DEF_TUNE (X86_TUNE_EXT_80387_CONSTANTS, "ext_80387_constants")
-DEF_TUNE (X86_TUNE_AVOID_VECTOR_DECODE, "avoid_vector_decode")
-DEF_TUNE (X86_TUNE_PROMOTE_HIMODE_IMUL, "promote_himode_imul")
-DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM32_MEM, "slow_imul_imm32_mem")
-DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM8, "slow_imul_imm8")
-DEF_TUNE (X86_TUNE_MOVE_M1_VIA_OR, "move_m1_via_or")
-DEF_TUNE (X86_TUNE_NOT_UNPAIRABLE, "not_unpairable")
-DEF_TUNE (X86_TUNE_NOT_VECTORMODE, "not_vectormode")
-DEF_TUNE (X86_TUNE_USE_VECTOR_FP_CONVERTS, "use_vector_fp_converts")
-DEF_TUNE (X86_TUNE_USE_VECTOR_CONVERTS, "use_vector_converts")
-DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH, "fuse_cmp_and_branch")
-DEF_TUNE (X86_TUNE_OPT_AGU, "opt_agu")
-DEF_TUNE (X86_TUNE_VECTORIZE_DOUBLE, "vectorize_double")
-DEF_TUNE (X86_TUNE_SOFTWARE_PREFETCHING_BENEFICIAL, "software_prefetching_beneficial")
-DEF_TUNE (X86_TUNE_AVX128_OPTIMAL, "avx128_optimal")
-DEF_TUNE (X86_TUNE_REASSOC_INT_TO_PARALLEL, "reassoc_int_to_parallel")
-DEF_TUNE (X86_TUNE_REASSOC_FP_TO_PARALLEL, "reassoc_fp_to_parallel")
-DEF_TUNE (X86_TUNE_GENERAL_REGS_SSE_SPILL, "general_regs_sse_spill")
-DEF_TUNE (X86_TUNE_AVOID_MEM_OPND_FOR_CMOVE, "avoid_mem_opnd_for_cmove")
-DEF_TUNE (X86_TUNE_SPLIT_MEM_OPND_FOR_FP_CONVERTS, "split_mem_opnd_for_fp_converts")
+/* X86_TUNE_USE_LEAVE: Leave does not affect Nocona SPEC2000 results
+   negatively, so enabling for Generic64 seems like good code size
+   tradeoff.  We can't enable it for 32bit generic because it does not
+   work well with PPro base chips.  */
+DEF_TUNE (X86_TUNE_USE_LEAVE, "use_leave", 
+	  m_386 | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC64)
+DEF_TUNE (X86_TUNE_PUSH_MEMORY, "push_memory", 
+          m_386 | m_P4_NOCONA | m_CORE_ALL | m_K6_GEODE | m_AMD_MULTIPLE 
+          | m_GENERIC)
+DEF_TUNE (X86_TUNE_ZERO_EXTEND_WITH_AND, "zero_extend_with_and",  m_486 | m_PENT)
+DEF_TUNE (X86_TUNE_UNROLL_STRLEN, "unroll_strlen",
+	 m_486 | m_PENT | m_PPRO | m_ATOM | m_SLM | m_CORE_ALL | m_K6
+	 | m_AMD_MULTIPLE | m_GENERIC)
+/* 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)
+DEF_TUNE (X86_TUNE_DOUBLE_WITH_ADD, "double_with_add", ~m_386)
+DEF_TUNE (X86_TUNE_USE_SAHF, "use_sahf",
+          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE
+          | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | 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_ATOM | m_SLM | m_GEODE 
+          | m_AMD_MULTIPLE  | m_GENERIC)
+/* X86_TUNE_PARTIAL_REG_STALL: We probably ought to watch for partial
+   register stalls on Generic32 compilation setting as well.  However
+   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.  Because this option
+   pays back little on PPro based chips and is in conflict with partial reg
+   dependencies used by Athlon/P4 based chips, it is better to leave it off
+   for generic32 for now.  */
+DEF_TUNE (X86_TUNE_PARTIAL_REG_STALL, "partial_reg_stall", m_PPRO)
+DEF_TUNE (X86_TUNE_PARTIAL_FLAG_REG_STALL, "partial_flag_reg_stall",
+          m_CORE_ALL | m_GENERIC)
+/* 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)
+DEF_TUNE (X86_TUNE_USE_HIMODE_FIOP, "use_himode_fiop", 
+          m_386 | m_486 | m_K6_GEODE)
+DEF_TUNE (X86_TUNE_USE_SIMODE_FIOP, "use_simode_fiop",
+          ~(m_PENT | m_PPRO | m_CORE_ALL | m_ATOM 
+            | m_SLM | m_AMD_MULTIPLE | m_GENERIC))
+DEF_TUNE (X86_TUNE_USE_MOV0, "use_mov0", m_K6)
+DEF_TUNE (X86_TUNE_USE_CLTD, "use_cltd", ~(m_PENT | m_ATOM | m_SLM | m_K6))
+/* X86_TUNE_USE_XCHGB: Use xchgb %rh,%rl instead of rolw/rorw $8,rx.  */
+DEF_TUNE (X86_TUNE_USE_XCHGB, "use_xchgb", m_PENT4)
+DEF_TUNE (X86_TUNE_SPLIT_LONG_MOVES, "split_long_moves", m_PPRO)
+DEF_TUNE (X86_TUNE_READ_MODIFY_WRITE, "read_modify_write", ~m_PENT)
+DEF_TUNE (X86_TUNE_READ_MODIFY, "read_modify", ~(m_PENT | m_PPRO))
+DEF_TUNE (X86_TUNE_PROMOTE_QIMODE, "promote_qimode",
+          m_386 | m_486 | m_PENT | m_CORE_ALL | m_ATOM | m_SLM 
+          | m_K6_GEODE | m_AMD_MULTIPLE | m_GENERIC)
+DEF_TUNE (X86_TUNE_FAST_PREFIX, "fast_prefix", ~(m_386 | m_486 | m_PENT))
+DEF_TUNE (X86_TUNE_SINGLE_STRINGOP, "single_stringop", m_386 | m_P4_NOCONA)
+DEF_TUNE (X86_TUNE_QIMODE_MATH, "qimode_math", ~0)
+/* X86_TUNE_HIMODE_MATH: On PPro this flag is meant to avoid partial
+   register stalls.  Just like X86_TUNE_PARTIAL_REG_STALL this option
+   might be considered for Generic32 if our scheme for avoiding partial
+   stalls was more effective.  */
+DEF_TUNE (X86_TUNE_HIMODE_MATH, "himode_math", ~m_PPRO)
+DEF_TUNE (X86_TUNE_PROMOTE_QI_REGS, "promote_qi_regs", 0)
+DEF_TUNE (X86_TUNE_PROMOTE_HI_REGS, "promote_hi_regs", m_PPRO)
+/* 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)
+/* 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_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_ATOM | m_SLM 
+          | m_GEODE | m_AMD_MULTIPLE | m_GENERIC))
+DEF_TUNE (X86_TUNE_PARTIAL_REG_DEPENDENCY, "partial_reg_dependency",
+          m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE 
+          | m_GENERIC)
+/* X86_TUNE_SSE_PARTIAL_REG_DEPENDENCY: In the Generic model we have a
+   conflict here in between PPro/Pentium4 based chips that thread 128bit
+   SSE registers as single units versus K8 based chips that divide SSE
+   registers to two 64bit halves.  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_ATOM | m_SLM | m_AMDFAM10 
+          | m_BDVER | m_GENERIC)
+DEF_TUNE (X86_TUNE_SSE_UNALIGNED_LOAD_OPTIMAL, "sse_unaligned_load_optimal",
+          m_COREI7 | m_AMDFAM10 | m_BDVER | m_BTVER | m_SLM)
+DEF_TUNE (X86_TUNE_SSE_UNALIGNED_STORE_OPTIMAL, "sse_unaligned_store_optimal",
+          m_COREI7 | m_BDVER | m_SLM)
+DEF_TUNE (X86_TUNE_SSE_PACKED_SINGLE_INSN_OPTIMAL, "sse_packed_single_insn_optimal",
+          m_BDVER)
+/* 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)
+DEF_TUNE (X86_TUNE_SSE_TYPELESS_STORES, "sse_typeless_stores", m_AMD_MULTIPLE)
+DEF_TUNE (X86_TUNE_SSE_LOAD0_BY_PXOR, "sse_load0_by_pxor", m_PPRO | m_P4_NOCONA)
+DEF_TUNE (X86_TUNE_MEMORY_MISMATCH_STALL, "memory_mismatch_stall",
+          m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC)
+DEF_TUNE (X86_TUNE_PROLOGUE_USING_MOVE, "prologue_using_move", 
+          m_PPRO | m_ATHLON_K8)
+DEF_TUNE (X86_TUNE_EPILOGUE_USING_MOVE, "epilogue_using_move",
+          m_PPRO | m_ATHLON_K8)	
+DEF_TUNE (X86_TUNE_SHIFT1, "shift1", ~m_486)
+DEF_TUNE (X86_TUNE_USE_FFREEP, "use_ffreep", m_AMD_MULTIPLE)
+DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_TO_VEC, "inter_unit_moves_to_vec",
+          ~(m_AMD_MULTIPLE | m_GENERIC))
+DEF_TUNE (X86_TUNE_INTER_UNIT_MOVES_FROM_VEC, "inter_unit_moves_from_vec",
+          ~m_ATHLON_K8)
+DEF_TUNE (X86_TUNE_INTER_UNIT_CONVERSIONS, "inter_unit_conversions",
+          ~(m_AMDFAM10 | m_BDVER ))
+/* 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_CORE_ALL | m_ATOM | m_SLM| m_AMD_MULTIPLE 
+          | m_GENERIC)
+DEF_TUNE (X86_TUNE_SCHEDULE, "schedule",
+          m_PENT | m_PPRO | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE 
+          | m_AMD_MULTIPLE | m_GENERIC)
+DEF_TUNE (X86_TUNE_USE_BT, "use_bt",
+          m_CORE_ALL | m_ATOM | m_SLM | m_AMD_MULTIPLE | m_GENERIC)
+DEF_TUNE (X86_TUNE_USE_INCDEC, "use_incdec",
+          ~(m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_GENERIC))
+DEF_TUNE (X86_TUNE_PAD_RETURNS, "pad_returns",
+          m_CORE_ALL | m_AMD_MULTIPLE | m_GENERIC)
+DEF_TUNE (X86_TUNE_PAD_SHORT_FUNCTION, "pad_short_function", m_ATOM)
+DEF_TUNE (X86_TUNE_EXT_80387_CONSTANTS, "ext_80387_constants",
+          m_PPRO | m_P4_NOCONA | m_CORE_ALL | m_ATOM | m_SLM | m_K6_GEODE
+          | m_ATHLON_K8 | m_GENERIC)
+DEF_TUNE (X86_TUNE_AVOID_VECTOR_DECODE, "avoid_vector_decode",
+          m_CORE_ALL | m_K8 | m_GENERIC64)
+/* 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_SLOW_IMUL_IMM32_MEM: Imul of 32-bit constant and memory is
+   vector path on AMD machines.  */
+DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM32_MEM, "slow_imul_imm32_mem",
+          m_CORE_ALL | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64)
+/* X86_TUNE_SLOW_IMUL_IMM8: Imul of 8-bit constant is vector path on AMD
+   machines.  */
+DEF_TUNE (X86_TUNE_SLOW_IMUL_IMM8, "slow_imul_imm8",
+          m_CORE_ALL | m_K8 | m_AMDFAM10 | m_BDVER | m_BTVER | m_GENERIC64)
+/* 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_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_USE_VECTOR_FP_CONVERTS: Prefer vector packed SSE conversion
+   from FP to FP. */
+DEF_TUNE (X86_TUNE_USE_VECTOR_FP_CONVERTS, "use_vector_fp_converts",
+          m_CORE_ALL | m_AMDFAM10 | m_GENERIC)
+/* 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_FUSE_CMP_AND_BRANCH: Fuse a compare or test instruction
+   with a subsequent conditional jump instruction into a single
+   compare-and-branch uop.  */
+DEF_TUNE (X86_TUNE_FUSE_CMP_AND_BRANCH, "fuse_cmp_and_branch", m_BDVER)
+/* 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_ATOM | m_SLM)
+/* X86_TUNE_VECTORIZE_DOUBLE: Enable double precision vector
+   instructions.  */
+DEF_TUNE (X86_TUNE_VECTORIZE_DOUBLE, "vectorize_double", ~m_ATOM)
+/* 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_AVX128_OPTIMAL: Enable 128-bit AVX instruction generation for
+   the auto-vectorizer.  */
+DEF_TUNE (X86_TUNE_AVX128_OPTIMAL, "avx128_optimal", m_BDVER | m_BTVER2)
+/* 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_ATOM)
+/* 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_ATOM | m_SLM | m_HASWELL | m_BDVER1 | m_BDVER2)
+/* 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_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_ATOM)
+/* 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_SLM)
Index: config/i386/i386.opt
===================================================================
--- config/i386/i386.opt	(revision 201645)
+++ config/i386/i386.opt	(working copy)
@@ -382,6 +382,13 @@  mtune-ctrl=
 Target RejectNegative Joined Var(ix86_tune_ctrl_string)
 Fine grain control of tune features
 
+mno-default
+Target RejectNegative Var(ix86_tune_no_default) Init(0)
+Clear all tune features
+
+mdump-tune-features
+Target RejectNegative Var(ix86_dump_tunes) Init(0)
+
 mabi=
 Target RejectNegative Joined Var(ix86_abi) Enum(calling_abi) Init(SYSV_ABI)
 Generate code that conforms to the given ABI
Index: doc/invoke.texi
===================================================================
--- doc/invoke.texi	(revision 201645)
+++ doc/invoke.texi	(working copy)
@@ -637,6 +637,7 @@  Objective-C and Objective-C++ Dialects}.
 
 @emph{i386 and x86-64 Options}
 @gccoptlist{-mtune=@var{cpu-type}  -march=@var{cpu-type} @gol
+-mtune-ctrl=@var{feature-list} -mdump-tune-features -mno-default @gol
 -mfpmath=@var{unit} @gol
 -masm=@var{dialect}  -mno-fancy-math-387 @gol
 -mno-fp-ret-in-387  -msoft-float @gol
@@ -14429,6 +14430,24 @@  supported architecture, using the approp
 the file containing the CPU detection code should be compiled without
 these options.
 
+@item -mdump-tune-features
+@opindex mdump-tune-features
+This option instructs GCC to dump the names of the x86 performance 
+tuning features and default settings. The names can be used in 
+@option{-mtune-ctrl=@var{feature-list}}.
+
+@item -mtune-ctrl=@var{feature-list}
+@opindex mtune-ctrl=@var{feature-list}
+This option is used to do fine grain control of x86 code generation features.
+@var{feature-list} is a comma separated list of @var{feature} names. See also
+@option{-mdump-tune-features}. When specified, the @var{feature} will be turned
+on if it is not preceded with @code{^}, otherwise, it will be turned off.
+
+@item -mno-default
+@opindex mno-default
+This option instructs GCC to turn off all tunable features. See also 
+@option{-mtune-ctrl=@var{feature-list}} and @option{-mdump-tune-features}.
+
 @item -mcld
 @opindex mcld
 This option instructs GCC to emit a @code{cld} instruction in the prologue