This patch fixes bug 16408, ldbl-128ibm expm1l returning NaN for some
large arguments.
The basic problem is that the approach of converting the exponent to
the form n * log(2) + y, where -0.5 <= y <= 0.5, then computing 2^n *
expm1(y) + (2^n - 1) falls over when 2^n overflows (starting slightly
before the point where expm1 overflows, when y is negative and n is
the least integer for which 2^n overflows). The ldbl-128 code, and
the x86/x86_64 code, make expm1l fall back to expl for large positive
arguments to avoid this issue. This patch makes the ldbl-128ibm code
do the same. (The problem appears for the particular argument in the
testsuite because the ldbl-128ibm code also uses an overflow threshold
that's for ldbl-128 and is too big for ldbl-128ibm, but the problem
described applies for large non-overflowing cases as well, although
during the freeze is not a suitable time for making the expm1 tests
cover cases close to overflow more thoroughly.)
This leaves some code for large positive arguments in expm1l that is
now dead. To keep the code for ldbl-128 and ldbl-128ibm similar, and
to avoid unnecessary changes during the freeze, the patch doesn't
remove it; instead I propose to file a bug in Bugzilla as a reminder
that this code (for overflow, including errno setting, and for
arguments of +Inf) is no longer needed and should be removed from both
those expm1l implementations.
Tested powerpc32.
* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (__expm1l): Use __expl
for large positive arguments.
This patch fixes bug 16407, spurious overflows from ldbl-128ibm coshl.
The implementation assumed that a high part (reinterpreted as an
integer) of the absolute value of the argument of 0x408633ce8fb9f87dLL
or more meant overflow, but the actual threshold has high part
0x408633ce8fb9f87eLL (and a negative low part). The patch adjusts the
threshold accordingly.
sinhl probably has the same issue, but I didn't get that far in adding
tests of special cases (such as just below and above overflow) before
the freeze and during the freeze is not a suitable time to add them
(as they'd require ulps to be regenerated again), so I'm not changing
that function for now; when I add more tests of special cases, we'll
discover whether sinhl indeed has this problem.
Tested powerpc32.
* sysdeps/ieee754/ldbl-128ibm/e_coshl.c (__ieee754_coshl):
Increase overflow threshold.
This patch fixes bug 16400, spurious underflow exceptions for ldbl-128
/ ldbl-128ibm lgammal with small positive arguments, by just using
-__logl (x) as the result in the problem cases (similar to the
previous fix for problems with small negative arguments).
Tested powerpc32, and also tested on mips64 that this does not require
ulps regeneration for the ldbl-128 case.
* sysdeps/ieee754/ldbl-128/e_lgammal_r.c (__ieee754_lgammal_r):
Return -__logl (x) for small positive arguments without evaluating
a polynomial.
This addresses a long standing collision between userspace headers and
kernel headers only on ia64 systems. All other types have a __ prefix
in the ptrace headers except these two. Let's finally namespace these.
Verified that at least strace still builds after this change, as well
as after deleting all the struct hacks it has specifically for ia64.
URL: https://sourceware.org/bugzilla/show_bug.cgi?id=762
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This patch fixes bug 16390, incorrect signs of zero results from
ldbl-128ibm atan2l, soft-float only. The problem is a longstanding
GCC bug with fabsl not being correct for signed zero for soft float,
and the fix is using -fno-builtin-fabsl as a workaround, as already
done for various other source files. Tested powerpc-nofpu.
* sysdeps/powerpc/nofpu/Makefile [$(subdir) = math]
(CFLAGS-e_atan2l.c): Use -fno-builtin-fabsl.
This patch fixes bug 16386, ldbl-128ibm logl inaccuracy (with
consequent inaccuracy for lgammal) for arguments where the high double
is subnormal, which showed up while attempting to regenerate ulps for
powerpc-nofpu for 2.19. The problem here is logic failing to allow
for subnormals when calculating the exponent of the argument. Tested
for powerpc-nofpu.
* sysdeps/ieee754/ldbl-128ibm/e_logl.c (__ieee754_logl): Adjust
numbers with subnormal high part when calculating exponent.
This patch fixes bug 16385, ldbl-128ibm asinhl inaccuracy, which
showed up while attempting to regenerate ulps for powerpc-nofpu for
2.19. The problem here was use of fabs instead of fabsl meaning large
arguments were reduced to the precision of double. Tested for
powerpc-nofpu.
* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Use fabsl not
fabs.
This patch fixes bug 16384, ldbl-128ibm acoshl inaccuracy, which
showed up while attempting to regenerate ulps for powerpc-nofpu for
2.19. There were two separate problems, use of __log1p instead of
__log1pl and an insufficiently accurate constant value for log 2
(which this patch replaces by use of M_LN2l), each of which could
cause substantial inaccuracy in affected cases.
Tested for powerpc-nofpu.
* sysdeps/ieee754/ldbl-128ibm/e_acoshl.c (ln2): Initialize with
M_LN2l.
(__ieee754_acoshl): Use __log1pl not __log1p.
nscd incorrectly returns a success even when the netgroup in question
is not found and adds a positive result in the cache. this patch
fixes this behaviour by adding a negative lookup entry to cache and
returning an error when the netgroup is not found.
Currently, when a user looks up a netgroup that does not have any
members, nscd goes into an infinite loop trying to find members in the
group. This is because it does not handle cases when getnetgrent
returns an NSS_STATUS_NOTFOUND (which is what it does on empty group).
Fixed to handle this in the same way as NSS_STATUS_RETURN, similar to
what getgrent does by itself.
The sp check has to be moved up to the start of the func since it now
makes a system call and that'll clobber a lot of registers.
URL: https://sourceware.org/bugzilla/show_bug.cgi?id=16372
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Perform sanity check only if we have_lock. Due to lockless nature of fastbins
we need to be careful derefencing pointers to fastbin entries (chunksize(old)
in this case) in multithreaded environments.
The fix is to add have_lock to the if-condition checks. The rest of the patch
only makes code more readable.
* malloc/malloc.c (_int_free): Perform sanity check only if we
have_lock.
This patch fixes bug 16337, ldbl-128 lgammal spurious overflows for
small negative arguments (the arguments in question are already in the
testsuite). The implementation uses the reflection formula to compute
lgamma of negative x from lgamma of -x, effectively resulting in a
calculation -log(x^2) + log(-x); cancellation isn't problematic in
this case (bugs for problematic cancellation in lgamma are 2542, 2543,
2558), but the x^2 calculation can underflow (in which case there is
spurious logic to return an overflowing value - lgamma can only ever
correctly overflow for large positive arguments, though tgamma can
overflow for small arguments of either sign as well as large positive
arguments). The fix is simply to calculate the result directly with
logl when the argument is a small enough negative number.
Tested mips64.
* sysdeps/ieee754/ldbl-128/e_lgammal_r.c (__ieee754_lgammal_r):
Calculate results for small negative arguments directly rather
than using reflection formula with special underflow handling.
This patch fixes bug 16356, bad results from x86 / x86_64 expl /
exp10l in directed rounding modes, the most serious of the bugs shown
up by my patch expanding libm test coverage. When I fixed bug 16293,
I thought it was only necessary to set round-to-nearest when using
frndint in expm1 functions, because in other cases the cancellation
error from having the resulting fractional part close to 1 or -1 would
not be significant. However, in expl and exp10l, the way the final
fractional part gets computed (something more complicated than a
simple subtraction, because more precision is needed than you'd get
that way) can result in a value outside the range [-1, 1] when the
argument to frndint was very close to an integer and was rounded the
"wrong" way because of the rounding mode - and the f2xm1 instruction
has undefined results if its argument is outside [-1, 1], so resulting
in the large errors seen. So this patch removes the USE_AS_EXPM1L
conditionals on the round-to-nearest settings, so all of expl, expm1l
and exp10l now get round-to-nearest used for frndint (meaning the
final fractional part can at most be slightly above 0.5 in
magnitude). Associated tests of exp and exp10 are added and testing
of exp10 in directed rounding modes enabled.
Tested x86_64 and x86 and ulps updated accordingly.
* sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL): Also set
round-to-nearest for [!USE_AS_EXPM1L].
* sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL): Likewise.
* math/auto-libm-test-in: Do not expect cosh tests to fail. Add
more tests of exp and exp10. Expect some exp10 tests to miss
exceptions or fail in directed rounding modes.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (exp10_tonearest_test_data): New array.
(exp10_test_tonearest): New function.
(exp10_towardzero_test_data): New array.
(exp10_test_towardzero): New function.
(exp10_downward_test_data): New array.
(exp10_test_downward): New function.
(exp10_upward_test_data): New array.
(exp10_test_upward): New function.
(main): Call the new functions.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Bug 16293 is inaccuracy of x86/x86_64 versions of expm1, near 0 in
directed rounding modes, that arises from frndint rounding the
exponent to 1 or -1 instead of 0, resulting in large cancellation
error. This inaccuracy in turn affects other functions such as sinh
that use expm1. This patch fixes the problem by setting
round-to-nearest mode temporarily around the affected calls to
frndint. I don't think this is needed for other uses of frndint, such
as in exp itself, as only for expm1 is the cancellation error
significant.
Tested x86_64 and x86 and ulps updated accordingly.
* sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Set
round-to-nearest mode when using frndint.
* sysdeps/i386/fpu/s_expm1.S (__expm1): Likewise.
* sysdeps/i386/fpu/s_expm1f.S (__expm1f): Likewise.
* sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]:
Likewise.
* math/auto-libm-test-in: Add more tests of expm1. Do not expect
sinh test to fail.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (TEST_COND_x86_64): Remove macro.
(TEST_COND_x86): Likewise.
(expm1_tonearest_test_data): New array.
(expm1_test_tonearest): New function.
(expm1_towardzero_test_data): New array.
(expm1_test_towardzero): New function.
(expm1_downward_test_data): New array.
(expm1_test_downward): New function.
(expm1_upward_test_data): New array.
(expm1_test_upward): New function.
(main): Run the new test functions.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
This patch adds a feature test macro _DEFAULT_SOURCE to enable the
default set of header declarations.
The intention is: if _DEFAULT_SOURCE is not used there is no change to
the set of __USE_* macros glibc defines; if it's used on its own, and
without compiler options such as -std=c99 that define __STRICT_ANSI__,
again, there is no change; if it's used together with the macros it
approximately (i.e., apart from __USE_POSIX_IMPLICITLY) implies
(-D_BSD_SOURCE -D_SVID_SOURCE -D_POSIX_C_SOURCE=200809L), again, there
is no change. Otherwise, it causes the relevant features to be
enabled, even if __STRICT_ANSI__, or another feature test macro, would
cause them to be disabled.
This macro deliberately bundles the POSIX.1-2008 (non-X/Open)
functionality with the BSD/SVID/"misc" functionality, rather than
defining a macro that gives just the latter, as many of the header
cleanups resulting from removing _BSD_SOURCE and _SVID_SOURCE support
are only possible when BSD/SVID/"misc" is always bundled with
POSIX.1-2008.
Tested x86_64.
* include/features.h: Update comment documenting feature test
macros. Mention _DEFAULT_SOURCE in comment.
[_GNU_SOURCE] (_DEFAULT_SOURCE): Undefine and redefine.
[_DEFAULT_SOURCE]: Undefine and redefine _DEFAULT_SOURCE,
_BSD_SOURCE and _SVID_SOURCE.
[!__STRICT_ANSI__ && !_ISOC99_SOURCE && !_POSIX_SOURCE &&
!_POSIX_C_SOURCE && !_XOPEN_SOURCE && !_BSD_SOURCE &&
!_SVID_SOURCE]: Likewise.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(__USE_POSIX_IMPLICITLY): Define.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(_POSIX_SOURCE): Undefine and redefine.
[_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE]
(_POSIX_C_SOURCE): Likewise.
* manual/creature.texi (_DEFAULT_SOURCE): Document.
(Feature Test Macros): Update documentation of default features.
This patch fixes bug 16338, ldbl-128 logl not handling subnormals
(with consequent inaccuracy for lgammal as well). The fix is simply
to use __frexpl when determining the exponent, as done already in
log2l and log10l. Given the lack of testing of small arguments to any
of the log* functions, appropriate tests are added for all of them.
Tested x86_64 and x86 and ulps updated accordingly, and spot tests
also run for mips64 to confirm the ldbl-128 fix.
Note that while this fixes lgammal inaccuracy for small positive
arguments, I suspect that there will still be problems with spurious
underflows in that case.
* sysdeps/ieee754/ldbl-128/e_logl.c (__ieee754_logl): Use __frexpl
to determine exponent and adjust argument to have exponent of -1.
* math/auto-libm-test-in: Add more tests of log, log10, log1p and
log2.
* math/auto-libm-test-out: Regenerated.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
This is needed for version-3 tz-format files; it supports time
stamps past 2037 for America/Godthab (the only entry in the tz
database for which this change is relevant).
* manual/time.texi (TZ Variable): Document transition times
from -167:59:59 through -00:00:01.
* time/tzset.c (tz_rule): Time of day is now signed.
(__tzset_parse_tz): Parse negative time of day.
A sse42 version of strstr used pcmpistr instruction which is quite
ineffective. A faster way is look for pairs of characters which is uses
sse2, is faster than pcmpistr and for real strings a pairs we look for
are relatively rare.
For linear time complexity we use buy or rent technique which switches
to two-way algorithm when superlinear behaviour is detected.
