[PATCHv4] sysdeps/ieee754/soft-fp: ignore maybe-uninitialized with -O [BZ #19444]

[Adhemerval Zanella]

On 03/01/2019 12:44, Mark Corbin wrote:
> 
> 
> On 01/10/2018 17:26, Martin Jansa wrote:
>> ---
>>  ChangeLog                        |  4 ++++
>>  sysdeps/ieee754/soft-fp/s_fdiv.c | 12 ++++++++++++
>>  2 files changed, 16 insertions(+)
>>
>> diff --git a/ChangeLog b/ChangeLog
>> index 4bafeefda5..9cdf59c9ab 100644
>> --- a/ChangeLog
>> +++ b/ChangeLog
>> @@ -1,3 +1,7 @@
>> +2018-09-30  Martin Jansa  <Martin.Jansa@gmail.com>
>> +	Partial fix for [BZ #23716]
>> +	* sysdeps/ieee754/soft-fp/s_fdiv.c: Fix build with -O.
>> +
>>  2018-09-29  Martin Jansa  <Martin.Jansa@gmail.com>
>>  	Partial fix for [BZ #23716]
>>  	* sysdeps/ieee754/dbl-96/e_jnl.c: Fix build with -O
>> diff --git a/sysdeps/ieee754/soft-fp/s_fdiv.c b/sysdeps/ieee754/soft-fp/s_fdiv.c
>> index 341339f5ed..f124edd760 100644
>> --- a/sysdeps/ieee754/soft-fp/s_fdiv.c
>> +++ b/sysdeps/ieee754/soft-fp/s_fdiv.c
>> @@ -25,6 +25,16 @@
>>  #undef fdivl
>>  
>>  #include <math-narrow.h>
>> +
>> +#include <libc-diag.h>
>> +/* R_f[01] are not set in cases where it is not used in packing, but the
>> +   compiler does not see that it is set in all cases where it is
>> +   used, resulting in warnings that it may be used uninitialized.
>> +   The location of the warning differs in different versions of GCC,
>> +   it may be where R is defined using a macro or it may be where the
>> +   macro is defined. This happens only with -O1.  */
>> +DIAG_PUSH_NEEDS_COMMENT;
>> +DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
>>  #include <soft-fp.h>
>>  #include <single.h>
>>  #include <double.h>
>> @@ -53,4 +63,6 @@ __fdiv (double x, double y)
>>    CHECK_NARROW_DIV (ret, x, y);
>>    return ret;
>>  }
>> +DIAG_POP_NEEDS_COMMENT;
>> +
>>  libm_alias_float_double (div)
> 
> Hello
> 
> It would be really helpful if this fix (commit id
> 4a06ceea33ecc220bbfe264d8f1e74de2f04e90d) could be backported from
> master to the release/2.28/master branch.
> 
> This would allow all glibc 2.28 patches to be dropped from Buildroot.
> 
> Thanks
> 
> Mark
> 

Done.