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Re: [google][4.8] Expose all target specific builtins unconditionally for LIPO builds


the patch is ok.

thanks,

David

On Thu, Jul 25, 2013 at 2:53 PM, Sriraman Tallam <tmsriram@google.com> wrote:
> On Wed, Jul 24, 2013 at 3:21 PM, Xinliang David Li <davidxl@google.com> wrote:
>> Can you collect some number on ggc_memory increase  with this change
>> in profile_gen build -- the value is recorded gcov_module_info object
>> in coverage.c.
>
> The ggc_memory increase if < 0.2% for large modules (initial usage
> around 100MB and greater).  For some small modules, whose initial
> parser memory usage is around 2MB, I see a 80% increase.
>
> Thanks
> Sri
>
>>
>> thanks,
>>
>> David
>>
>> On Wed, Jul 24, 2013 at 3:14 PM, Sriraman Tallam <tmsriram@google.com> wrote:
>>> The following test-case fails in LIPO mode during profile-use build:
>>>
>>> main.ccthe
>>> ------------
>>> __attribute__((target("sse4.2")))
>>> unsigned int problem_aux (unsigned int A, unsigned int B);
>>>
>>>
>>> int main (int argc, char *argv[])
>>> {
>>>   return problem_aux (0, 0);
>>> }
>>>
>>> aux.cc
>>> ---------
>>> __attribute__((target("sse4.2")))
>>> unsigned int problem_aux (unsigned int A, unsigned int B)
>>> {
>>>   return __builtin_ia32_crc32qi (A, B);
>>> }
>>>
>>> $ g++ -O2 -fprofile-generate main.cc aux.cc
>>> $ ./a.out
>>> $ g++ -O2 -fprofile-use main.cc
>>> error: '__builtin_ia32_crc32qi' was not declared in this scope
>>>
>>> This happens when parsing the auxiliary module. __builtin_ia32_crc32qi
>>> is a target specific builtin that gets created after the target
>>> attribute is seen in the declaration of problem_aux in the primary
>>> module. This is too late for adding theisbuiltin to the list of
>>> knowns, the buitlins get saved when cp_save_built_in_decl_pre_parsing
>>> in cp/cp-objcp-common.c is called much earlier.  Hence, this builtin
>>> which is created during primary module parsing is not available when
>>> parsing the auxiliary module.
>>>
>>> A simple fix is to expose all target builtins unconditionally in LIPO
>>> mode. Patch:
>>>
>>>
>>> Index: config/i386/i386.c
>>> ===================================================================
>>> --- config/i386/i386.c  (revision 201046)
>>> +++ config/i386/i386.c  (working copy)
>>> @@ -26957,7 +26957,8 @@ def_builtin (HOST_WIDE_INT mask, const char *name,
>>>        ix86_builtins_isa[(int) code].isa = mask;
>>>
>>>        mask &= ~OPTION_MASK_ISA_64BIT;
>>> -      if (mask == 0
>>> +      if (flag_dyn_ipa
>>> +         || mask == 0
>>>           || (mask & ix86_isa_flags) != 0
>>>           || (lang_hooks.builtin_function
>>>               == lang_hooks.builtin_function_ext_scope))
>>>
>>>
>>> Is this ok?
>>>
>>> Thanks
>>> Sri


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