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Make fallback fegetexceptflag work with generic fetestexceptflag. 

The generic implementation of fetestexceptflag does:

int
fetestexceptflag (const fexcept_t *flagp, int excepts)
{
  /* Most versions of fegetexceptflag store exceptions in a form such
     that this works.  */
  return *flagp & excepts & FE_ALL_EXCEPT;
}

In the case where FE_ALL_EXCEPT is nonzero but exceptions may not be
supported at runtime, this only works if fegetexceptflag cleared all
the bits of FE_ALL_EXCEPT in *flagp; otherwise it accesses
uninitialized data.  This showed up as a failure of
math/test-fetestexceptflag for MIPS o32 soft-float.  This patch makes
the fallback fegetexceptflag store 0 (fexcept_t is an integer type
everywhere) so that this works.  (No bug report in Bugzilla because
this wasn't user-visible - at least, without using tools to detect
uninitialized memory use at runtime - without fetestexceptflag, which
is new in 2.25.)

Tested for MIPS o32 soft-float.

	* math/fgetexcptflg.c (__fegetexceptflag): Store 0 in fexcept_t
	object.
This commit is contained in:
Joseph Myers 2017-01-12 01:52:37 +00:00
parent 6a1cefac19
commit 4dfb9c9411
2 changed files with 6 additions and 0 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2017-01-12 Joseph Myers <joseph@codesourcery.com>
* math/fgetexcptflg.c (__fegetexceptflag): Store 0 in fexcept_t
object.
2017-01-11 Joseph Myers <joseph@codesourcery.com> 2017-01-11 Joseph Myers <joseph@codesourcery.com>
[BZ #16458] [BZ #16458]

1
math/fgetexcptflg.c
View File

@ -24,6 +24,7 @@ int
__fegetexceptflag (fexcept_t *flagp, int excepts) __fegetexceptflag (fexcept_t *flagp, int excepts)
{ {
/* Nothing to do. */ /* Nothing to do. */
*flagp = 0;
return 0; return 0;
} }
#if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2) #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)