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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 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 

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

Tested for x86_64 (with GCC 7).

2017-08-21  Joseph Myers  <>

	* 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)
 		/* #### Last used is 50/150/250 ### */
+	    default:
+		__builtin_unreachable ();
 	return exc.retval;

Joseph S. Myers

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