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Fix MIPS libc_feresetround*_ctx to preserve exceptions.

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Testing on mips64 showed missing underflow exceptions (from exp, for
example) in non-default rounding modes, caused by
libc_feresetround*_ctx wrongly restoring a saved environment without
preserving exceptions, when that's only valid for the _noex variants.
(I don't know why Steve didn't see this in his testing.)  This patch
fixes this by using libc_feupdateenv_mips_ctx for the relevant macros
and removing the problem definitions.

The problem definitions aren't suitable for the _noex macros either
because they only discard exceptions in non-default rounding modes,
and while for some uses of *_noex/*_NOEX it doesn't matter whether
exceptions are discarded, dbl-64/e_remainder.c requires
SET_RESTORE_ROUND_NOEX to cause exceptions to be discarded.  I think
the accumulated set of macros / functions for optimized exception /
rounding mode handling could do with a careful review by now, and
possible refactoring, and at least one new feature (extracting the
saved rounding mode from an environment / context variable - see
dbl-64/e_sqrt.c for a case where this could be used).

Tested mips64.

	* sysdeps/mips/math_private.h [__mips_hard_float]
	(libc_feresetround_ctx): Define to libc_feupdateenv_mips_ctx not
	libc_feresetround_mips_ctx.
	[__mips_hard_float] (libc_feresetroundf_ctx): Likewise.
	[__mips_hard_float] (libc_feresetroundl_ctx): Likewise.
	[__mips_hard_float] (libc_feresetround_mips_ctx): Remove.
This commit is contained in:
Joseph Myers 2014-03-11 22:30:40 +00:00
parent 600fa36158
commit 76c96cf7ec
2 changed files with 10 additions and 10 deletions
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7
ChangeLog
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@ -1,5 +1,12 @@
2014-03-11 Joseph Myers <joseph@codesourcery.com>
* sysdeps/mips/math_private.h [__mips_hard_float]
(libc_feresetround_ctx): Define to libc_feupdateenv_mips_ctx not
libc_feresetround_mips_ctx.
[__mips_hard_float] (libc_feresetroundf_ctx): Likewise.
[__mips_hard_float] (libc_feresetroundl_ctx): Likewise.
[__mips_hard_float] (libc_feresetround_mips_ctx): Remove.
[BZ #16677]
* math/s_nextafter.c (__nextafter): Do not return value from
overflowing computation.

13
sysdeps/mips/math_private.h
View File

@ -217,6 +217,9 @@ libc_feupdateenv_mips_ctx (struct rm_ctx *ctx)
# define libc_feupdateenv_ctx libc_feupdateenv_mips_ctx
# define libc_feupdateenvf_ctx libc_feupdateenv_mips_ctx
# define libc_feupdateenvl_ctx libc_feupdateenv_mips_ctx
# define libc_feresetround_ctx libc_feupdateenv_mips_ctx
# define libc_feresetroundf_ctx libc_feupdateenv_mips_ctx
# define libc_feresetroundl_ctx libc_feupdateenv_mips_ctx
static __always_inline void
libc_feholdsetround_mips_ctx (struct rm_ctx *ctx, int round)
@ -242,16 +245,6 @@ libc_feholdsetround_mips_ctx (struct rm_ctx *ctx, int round)
# define libc_feholdsetroundf_ctx libc_feholdsetround_mips_ctx
# define libc_feholdsetroundl_ctx libc_feholdsetround_mips_ctx
static __always_inline void
libc_feresetround_mips_ctx (struct rm_ctx *ctx)
{
if (__glibc_unlikely (ctx->updated_status))
_FPU_SETCW (ctx->env);
}
# define libc_feresetround_ctx libc_feresetround_mips_ctx
# define libc_feresetroundf_ctx libc_feresetround_mips_ctx
# define libc_feresetroundl_ctx libc_feresetround_mips_ctx
#endif
#include_next <math_private.h>