This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Obsolete matherr, _LIB_VERSION, libieee.a
On Mon, 21 Aug 2017, Adhemerval Zanella wrote:
> Joseph I am seeing the failure:
>
> ../sysdeps/ieee754/k_standard.c: In function ‘__kernel_standard’:
> ../sysdeps/ieee754/k_standard.c:943:12: error: ‘exc.retval’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> return exc.retval;
> ~~~^~~~~~~
> When building 'math/k_standard.o' with GCC 7.1.1 and 8.0.0 (built
> with build-many-glibcs.py). with patch on master. GCC 5.4/6.2.1 does
> not show this issue.
Thanks for pointing this out (my testing was with GCC 6). I've committed
this patch to use __builtin_unreachable in a default case to avoid this
error.
Fix GCC 7 build of k_standard.c.
This patch adds a default case to k_standard.c that calls
__builtin_unreachable, to avoid an uninitialized variable error from
GCC 7 (reported in
<https://sourceware.org/ml/libc-alpha/2017-08/msg01012.html>).
Tested for x86_64 (with GCC 7).
2017-08-21 Joseph Myers <joseph@codesourcery.com>
* sysdeps/ieee754/k_standard.c (__kernel_standard): Add default
case calling __builtin_unreachable.
diff --git a/sysdeps/ieee754/k_standard.c b/sysdeps/ieee754/k_standard.c
index 0a0201f..8f906bd 100644
--- a/sysdeps/ieee754/k_standard.c
+++ b/sysdeps/ieee754/k_standard.c
@@ -939,6 +939,9 @@ __kernel_standard(double x, double y, int type)
break;
/* #### Last used is 50/150/250 ### */
+
+ default:
+ __builtin_unreachable ();
}
return exc.retval;
}
--
Joseph S. Myers
joseph@codesourcery.com