[PATCHv4] sysdeps/ieee754/soft-fp: ignore maybe-uninitialized with -O [BZ #19444]
Commit Message
* with -O, -O1, -Os it fails with:
In file included from ../soft-fp/soft-fp.h:318,
from ../sysdeps/ieee754/soft-fp/s_fdiv.c:28:
../sysdeps/ieee754/soft-fp/s_fdiv.c: In function '__fdiv':
../soft-fp/op-2.h:98:25: error: 'R_f1' may be used uninitialized in this function [-Werror=maybe-uninitialized]
X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) \
^~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f1' was declared here
FP_DECL_D (R);
^
../soft-fp/op-2.h:37:36: note: in definition of macro '_FP_FRAC_DECL_2'
_FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
^
../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
# define FP_DECL_D(X) _FP_DECL (2, X)
^~~~~~~~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
FP_DECL_D (R);
^~~~~~~~~
../soft-fp/op-2.h:101:17: error: 'R_f0' may be used uninitialized in this function [-Werror=maybe-uninitialized]
: (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0)); \
^~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f0' was declared here
FP_DECL_D (R);
^
../soft-fp/op-2.h:37:14: note: in definition of macro '_FP_FRAC_DECL_2'
_FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
^
../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
# define FP_DECL_D(X) _FP_DECL (2, X)
^~~~~~~~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
FP_DECL_D (R);
^~~~~~~~~
Build tested with Yocto for ARM, AARCH64, X86, X86_64, PPC, MIPS, MIPS64
with -O, -O1, -Os.
For AARCH64 it needs one more fix in locale for -Os.
Partial fix for [BZ #23716]
* sysdeps/ieee754/soft-fp/s_fdiv.c: Fix build with -O
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
ChangeLog | 4 ++++
sysdeps/ieee754/soft-fp/s_fdiv.c | 12 ++++++++++++
2 files changed, 16 insertions(+)
Comments
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
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.
@@ -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
@@ -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)