On AMD processors, memcpy optimized with unaligned SSE load is
slower than emcpy optimized with aligned SSSE3 while other string
functions are faster with unaligned SSE load. A feature bit,
Fast_Unaligned_Copy, is added to select memcpy optimized with
unaligned SSE load.
[BZ #19583]
* sysdeps/x86/cpu-features.c (init_cpu_features): Set
Fast_Unaligned_Copy with Fast_Unaligned_Load for Intel
processors. Set Fast_Copy_Backward for AMD Excavator
processors.
* sysdeps/x86/cpu-features.h (bit_arch_Fast_Unaligned_Copy):
New.
(index_arch_Fast_Unaligned_Copy): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check
Fast_Unaligned_Copy instead of Fast_Unaligned_Load.
Since commit 44d20bca52 (Implement
second fallback mode for DNS requests), there is a code path which
returns early, before *resplen2 is initialized. This happens if the
name server address is immediately recognized as invalid (because of
lack of protocol support, or if it is a broadcast address such
255.255.255.255, or another invalid address).
If this happens and *resplen2 was non-zero (which is the case if a
previous query resulted in a failure), __libc_res_nquery would reuse
an existing second answer buffer. This answer has been previously
identified as unusable (for example, it could be an NXDOMAIN
response). Due to the presence of a second answer, no name server
switching will occur. The result is a name resolution failure,
although a successful resolution would have been possible if name
servers have been switched and queries had proceeded along the search
path.
The above paragraph still simplifies the situation. Before glibc
2.23, if the second answer needed malloc, the stub resolver would
still attempt to reuse the second answer, but this is not possible
because __libc_res_nsearch has freed it, after the unsuccessful call
to __libc_res_nquerydomain, and set the buffer pointer to NULL. This
eventually leads to an assertion failure in __libc_res_nquery:
/* Make sure both hp and hp2 are defined */
assert((hp != NULL) && (hp2 != NULL));
If assertions are disabled, the consequence is a NULL pointer
dereference on the next line.
Starting with glibc 2.23, as a result of commit
e9db92d3ac (CVE-2015-7547: getaddrinfo()
stack-based buffer overflow (Bug 18665)), the second answer is always
allocated with malloc. This means that the assertion failure happens
with small responses as well because there is no buffer to reuse, as
soon as there is a name resolution failure which triggers a search for
an answer along the search path.
This commit addresses the issue by ensuring that *resplen2 is
initialized before the send_dg function returns.
This commit also addresses a bug where an invalid second reply is
incorrectly returned as a valid to the caller.
Bug 19848 reports cases where powl on x86 / x86_64 has error
accumulation, for small integer exponents, larger than permitted by
glibc's accuracy goals, at least in some rounding modes. This patch
further restricts the exponent range for which the
small-integer-exponent logic is used to limit the possible error
accumulation.
Tested for x86_64 and x86 and ulps updated accordingly.
[BZ #19848]
* sysdeps/i386/fpu/e_powl.S (p3): Rename to p2 and change value
from 8 to 4.
(__ieee754_powl): Compare integer exponent against 4 not 8.
* sysdeps/x86_64/fpu/e_powl.S (p3): Rename to p2 and change value
from 8 to 4.
(__ieee754_powl): Compare integer exponent against 4 not 8.
* math/auto-libm-test-in: Add more tests of pow.
* math/auto-libm-test-out: Regenerated.
* sysdeps/i386/i686/fpu/multiarch/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
With the 2.6.32 minimum kernel on x86 and 3.2 on other architectures,
__NR_utimensat is always defined.
Changelog:
* sysdeps/unix/sysv/linux/futimens.c (futimens) [__NR_utimensat]:
Make code unconditional.
[!__NR_utimensat]: Remove conditional code.
* sysdeps/unix/sysv/linux/lutimes.c (lutimes) [__NR_utimensat]:
Make code unconditional.
[!__NR_utimensat]: Remove conditional code.
* sysdeps/unix/sysv/linux/utimensat.c (utimensat) [__NR_utimensat]:
Make code unconditional.
[!__NR_utimensat]: Remove conditional code.
With the 2.6.32 minimum kernel on x86 and 3.2 on other architectures,
__NR_openat is always defined.
Changelog:
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64) [__NR_openat]:
Make code unconditional.
The x86-specific versions of both pthread_cond_wait and
pthread_cond_timedwait have (in their fall-back-to-futex-wait slow
paths) calls to __pthread_mutex_cond_lock_adjust followed by
__pthread_mutex_unlock_usercnt, which load the parameters before the
first call but then assume that the first parameter, in %eax, will
survive unaffected. This happens to have been true before now, but %eax
is a call-clobbered register, and this assumption is not safe: it could
change at any time, at GCC's whim, and indeed the stack-protector canary
checking code clobbers %eax while checking that the canary is
uncorrupted.
So reload %eax before calling __pthread_mutex_unlock_usercnt. (Do this
unconditionally, even when stack-protection is not in use, because it's
the right thing to do, it's a slow path, and anything else is dicing
with death.)
* sysdeps/unix/sysv/linux/i386/pthread_cond_timedwait.S: Reload
call-clobbered %eax on retry path.
* sysdeps/unix/sysv/linux/i386/pthread_cond_wait.S: Likewise.
Since only Intel processors with AVX2 have fast unaligned load, we
should set index_arch_AVX_Fast_Unaligned_Load only for Intel processors.
Move AVX, AVX2, AVX512, FMA and FMA4 detection into get_common_indeces
and call get_common_indeces for other processors.
Add CPU_FEATURES_CPU_P and CPU_FEATURES_ARCH_P to aoid loading
GLRO(dl_x86_cpu_features) in cpu-features.c.
[BZ #19583]
* sysdeps/x86/cpu-features.c (get_common_indeces): Remove
inline. Check family before setting family, model and
extended_model. Set AVX, AVX2, AVX512, FMA and FMA4 usable
bits here.
(init_cpu_features): Replace HAS_CPU_FEATURE and
HAS_ARCH_FEATURE with CPU_FEATURES_CPU_P and
CPU_FEATURES_ARCH_P. Set index_arch_AVX_Fast_Unaligned_Load
for Intel processors with usable AVX2. Call get_common_indeces
for other processors with family == NULL.
* sysdeps/x86/cpu-features.h (CPU_FEATURES_CPU_P): New macro.
(CPU_FEATURES_ARCH_P): Likewise.
(HAS_CPU_FEATURE): Use CPU_FEATURES_CPU_P.
(HAS_ARCH_FEATURE): Use CPU_FEATURES_ARCH_P.
* malloc/Makefile ($(objpfx)tst-malloc-backtrace,
$(objpfx)tst-malloc-thread-exit, $(objpfx)tst-malloc-thread-fail): Use
$(shared-thread-library) instead of hardcoding the path to libpthread.
This patch removes the __ASSUME_GETDENTS64_SYSCALL macro, as its
definition is constant given the new kernel version requirements (and
was constant anyway before those requirements except for MIPS n32).
Note that the "#ifdef __NR_getdents64" conditional *is* still needed,
because MIPS n64 only has the getdents syscall (being a 64-bit ABI,
that syscall is 64-bit; the difference between the two on 64-bit
architectures is where d_type goes). If MIPS n64 were to gain the
getdents64 syscall and we wanted to use it conditionally on the kernel
version at runtime we'd have to revert this patch, but I think that's
unlikely (and in any case, we could follow the simpler approach of
undefining __NR_getdents64 if the syscall can't be assumed, just like
we do for accept4 / recvmmsg / sendmmsg syscalls on architectures
where socketcall support came first).
Most of the getdents.c changes are reindentation.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_GETDENTS64_SYSCALL): Remove macro.
* sysdeps/unix/sysv/linux/getdents.c
[!__ASSUME_GETDENTS64_SYSCALL]: Remove conditional code.
[!have_no_getdents64_defined]: Likewise.
(__GETDENTS): Remove __have_no_getdents64 conditional.
Current Linux kernel version requirements mean the signalfd4 syscall
can always be assumed to be available. This patch removes
__ASSUME_SIGNALFD4 and associated conditionals.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_SIGNALFD4):
Remove macro.
* sysdeps/unix/sysv/linux/signalfd.c: Do not include
<kernel-features.h>.
(signalfd) [__NR_signalfd4]: Make code unconditional.
(signalfd) [!__ASSUME_SIGNALFD4]: Remove conditional code.
This patch fixes the implicit check style add in 2a69f853c for the
general convention one.
Checked on x86_64.
* sysdeps/unix/sysv/linux/spawni.c (__spawnix): Fix implict checks
style.
When PLT may be used, JUMPTARGET should be used instead calling the
function directly.
* sysdeps/unix/sysv/linux/x86_64/cancellation.S
(__pthread_enable_asynccancel): Use JUMPTARGET to call
__pthread_unwind.
* sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S
(__condvar_cleanup2): Use JUMPTARGET to call _Unwind_Resume.
* sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
(__condvar_cleanup1): Likewise.
When installing glibc (w/mathvec enabled) in-place on a system with
a glibc w/out mathvec enabled, the install will clobber the existing
libm.so (e.g., /lib64/libm-2.21.so) with a linker script. This is
because libm.so is a symlink to libm.so.6 which is a symlink to the
final libm-2.21.so file. When the makefile writes the linker script
directly to libm.so, it gets clobbered.
The simple patch below to math/Makefile fixes this. It is based on
the nptl Makefile, which does exactly the same thing in a safer way.
Current Linux posix_spawn spawn do not test if the pid argument is
valid before trying to update it for success case. This patch fixes
it.
Tested on x86_64 and i686.
* sysdeps/unix/sysv/linux/spawni.c (__spawnix): Fix invalid memory
access where posix_spawn success and pid argument is null.
* posix/tst-spawn.c (do_test): Add posix_spawn null pid argument for
success case.
* sysdeps/generic/dl-fcntl.h: New file, adds attribute_hidden to __open
and __fcntl.
* sysdeps/mach/hurd/dl-fcntl.h: New file, adds attribute_hidden to
__fcntl only.
* include/fcntl.h [IS_IN (rtld)]: Include <dl-fcntl.h> instead of
adding attribute_hidden to __open and __fcntl.
Generating errnos.d does not actually need libc-modules.h.
* sysdeps/mach/hurd/Makefile ($(common-objpfx)errnos.d): Strip
"-include $(common-objpfx)libc-modules.h" from CPPFLAGS, and do not
depend on libc-modules.h,
Given current Linux kernel version requirements, we can assume the
presence of the eventfd2 syscall. This means that __ASSUME_EVENTFD2
can be removed, and a syscalls.list entry suffices for eventfd instead
of needing a .c file. This patch implements those changes.
Tested for x86_64 and x86 (not that that means much, given the lack of
testsuite coverage for eventfd).
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_EVENTFD2):
Remove macro.
* sysdeps/unix/sysv/linux/eventfd.c: Remove file.
* sysdeps/unix/sysv/linux/syscalls.list (eventfd): New syscall
entry.
Given current Linux kernel version requirements, we can always assume
the fallocate syscall to be available. This patch removes
__ASSUME_FALLOCATE and a test for whether __NR_fallocate is defined.
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_FALLOCATE):
Remove macro.
* sysdeps/unix/sysv/linux/wordsize-64/posix_fallocate.c: Do not
include <kernel-features.h>.
[!__ASSUME_FALLOCATE]: Remove conditional code.
(posix_fallocate) [__NR_fallocate]: Make code unconditional.
When building on i686, x86_64, and arm, and with NDEBUG, or --with-cpu
there are various variables and functions which are unused based on
these settings.
This patch marks all such variables with __attribute__((unused)) to
avoid the compiler warnings when building with the aformentioned
options.
With current kernel version requirements, the ppoll Linux syscall can
be assumed to be present on all architectures; this patch removes the
__ASSUME_PPOLL macro and conditionals on it and on whether __NR_ppoll
is defined. (Note that the same can't yet be done for pselect,
because MicroBlaze only wired that up in the syscall table in 3.15.)
Tested for x86_64 and x86 that installed stripped shared libraries are
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_PPOLL):
Remove macro.
* sysdeps/unix/sysv/linux/ppoll.c: Do not include
<kernel-features.h>.
[__NR_ppoll]: Make code unconditional.
[!__ASSUME_PPOLL]: Remove conditional code.
This patch adjusts the defaults for kernel-features.h macros relating
to availability of accept4, recvmmsg and sendmmsg. It is not intended
to affect which macros end up getting defined in any configuration.
At present, all architectures with syscalls for those functions need
to define __ASSUME_*_SYSCALL macros; in particular, any new
architecture needs its own kernel-features.h file for that purpose,
though it may not otherwise need such a header. Those macros are then
used together with __ASSUME_SOCKETCALL to define macros for whether
the functions in question are available.
This patch changes the defaults so that the syscalls are assumed to be
available by default with recent-enough kernels, and it is the
responsibility of architecture headers to undefine the macros if they
are unavailable in supported kernels at least as recent as the version
where the architecture-independent functionality was introduced. The
__ASSUME_<function> macros are defaulted similarly instead of being
defined based on other macros (defining based on other macros would no
longer work because the #undefs appear after the generic header is
included), so where the syscall being unavailable means the function
is unavailable this means the architecture header has to undefine the
__ASSUME_<function> macro; this only affects __ASSUME_ACCEPT4 for
ia64, as other cases where the syscalls were added late enough to be
relevant with current kernel version requirements are all on
socketcall architectures.
As a consequence, the AArch64 and Nios II kernel-features.h header
files are removed, and others simplified. When the minimum kernel
version becomes 4.3 or later on all architectures, the syscalls in
question can just be assumed unconditionally, permitting further
simplification.
Tested for x86_64, x86 and powerpc (that installed shared libraries
are unchanged by the patch, and testsuite for x86_64 and x86).
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Define unconditionally.
(__ASSUME_ACCEPT4): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Define.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG):
Likewise.
* sysdeps/unix/sysv/linux/aarch64/kernel-features.h: Remove file.
* sysdeps/unix/sysv/linux/nios2/kernel-features.h: Likewise.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Do not define.
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/arm/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/i386/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
* sysdeps/unix/sysv/linux/ia64/kernel-features.h
(__ASSUME_RECVMMSG_SYSCALL): Do not define.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x030300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x030300].
[__LINUX_KERNEL_VERSION < 0x030300] (__ASSUME_ACCEPT4): Undefine.
* sysdeps/unix/sysv/linux/m68k/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x030300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x030300].
* sysdeps/unix/sysv/linux/mips/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/powerpc/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/s390/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Undefine if [__LINUX_KERNEL_VERSION <
0x040300] instead of defining if [__LINUX_KERNEL_VERSION >=
0x040300].
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/sh/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Do not define.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/sparc/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/tile/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
(__ASSUME_RECVMMSG_SYSCALL): Likewise.
(__ASSUME_SENDMMSG_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/x86_64/kernel-features.h
(__ASSUME_ACCEPT4_SYSCALL): Likewise.
[__LINUX_KERNEL_VERSION >= 0x020621] (__ASSUME_RECVMMSG_SYSCALL):
Likewise.
[__LINUX_KERNEL_VERSION >= 0x030000] (__ASSUME_SENDMMSG_SYSCALL):
Likewise.
The number of currently defined nameservers is stored in ->nscount,
whereas ->_u._ext.nscount is set by __libc_res_nsend only after local
initializations.
This patch updates the glibc headers with the defines MADV_FREE,
IPV6_HDRINCL and EPOLLEXCLUSIVE that are added in Linux 4.5.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
* bits/mman-linux.h [__USE_MISC] (MADV_FREE): New macro.
* sysdeps/unix/sysv/linux/hppa/bits/mman.h [__USE_MISC]
(MADV_FREE): Likewise.
* sysdeps/unix/sysv/linux/bits/in.h (IPV6_HDRINCL): Likewise.
* sysdeps/unix/sysv/linux/sys/epoll.h (enum EPOLL_EVENTS): Add
EPOLLEXCLUSIVE.
A large number of the test-ldouble failures seen for ldbl-128ibm are
spurious "underflow" and "inexact" exceptions. These arise from such
exceptions in the underlying arithmetic; unlike other spurious
exceptions from that arithmetic, they do not in general relate to
cases where the returned result is also substantially inaccurate, are
not so readily avoidable by appropriately conditional libgcc patches,
and are widespread enough to be hard to handle through individual
XFAILing of the affected tests.
Thus, this patch documents relaxed accuracy goals for libm functions
for IBM long double and makes libm-test.inc reflect these spurious
exceptions in ldbl-128ibm arithmetic and always allow them in
ldbl-128ibm testing (while still not allowing these exceptions to be
missing where required to be present). Tested for powerpc.
* manual/math.texi (Errors in Math Functions): Document relaxed
accuracy goals for IBM long double.
* math/libm-test.inc (test_exceptions): Always allow spurious
"underflow" and "inexact" exceptions for IBM long double.
index_* and bit_* macros are used to access cpuid and feature arrays o
struct cpu_features. It is very easy to use bits and indices of cpuid
array on feature array, especially in assembly codes. For example,
sysdeps/i386/i686/multiarch/bcopy.S has
HAS_CPU_FEATURE (Fast_Rep_String)
which should be
HAS_ARCH_FEATURE (Fast_Rep_String)
We change index_* and bit_* to index_cpu_*/index_arch_* and
bit_cpu_*/bit_arch_* so that we can catch such error at build time.
[BZ #19762]
* sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
(EXTRA_LD_ENVVARS): Add _arch_ to index_*/bit_*.
* sysdeps/x86/cpu-features.c (init_cpu_features): Likewise.
* sysdeps/x86/cpu-features.h (bit_*): Renamed to ...
(bit_arch_*): This for feature array.
(bit_*): Renamed to ...
(bit_cpu_*): This for cpu array.
(index_*): Renamed to ...
(index_arch_*): This for feature array.
(index_*): Renamed to ...
(index_cpu_*): This for cpu array.
[__ASSEMBLER__] (HAS_FEATURE): Add and use field.
[__ASSEMBLER__] (HAS_CPU_FEATURE)): Pass cpu to HAS_FEATURE.
[__ASSEMBLER__] (HAS_ARCH_FEATURE)): Pass arch to HAS_FEATURE.
[!__ASSEMBLER__] (HAS_CPU_FEATURE): Replace index_##name and
bit_##name with index_cpu_##name and bit_cpu_##name.
[!__ASSEMBLER__] (HAS_ARCH_FEATURE): Replace index_##name and
bit_##name with index_arch_##name and bit_arch_##name.
In makecontext the FDE needs to be terminated before the return
trampoline otherwise backtrace called within a context created by
makecontext yields infinite backtrace.
This bug has been present for a long time, stdlib/tst-makecontext did
not fail until recent commit e535ce25. Tested on mips-linux-gnu and
mips64el-linux-gnuabi64 and mips-linux-gnu, no regression.
This fixes stdlib/tst-makecontext on MIPS.
Changelog:
[BZ #19792]
* sysdeps/unix/sysv/linux/mips/makecontext.S (__makecontext):
Terminate FDE before return label.
The ldbl-128ibm implementation of nearbyintl uses logic that only
works in round-to-nearest mode. This contrasts with rintl, which
works in all rounding modes.
Now, arguably nearbyintl could simply be aliased to rintl, given that
spurious "inexact" is generally allowed for ldbl-128ibm, even for the
underlying arithmetic operations. But given that the only point of
nearbyintl is to avoid "inexact", this patch follows the more
conservative approach of adding conditionals to the rintl
implementation to make it suitable for use to implement nearbyintl,
then builds it for nearbyintl with USE_AS_NEARBYINTL defined. The
test test-nearbyint-except-2 shows up issues when traps on "inexact"
are enabled, which turn out to be problems with the powerpc
fenv_private.h implementation (two functions that should disable
exception traps potentially failing to do so in some cases); this
patch duly fixes that as well (I don't see any other existing cases
where this would be user-visible; there isn't much use of *_NOEX,
*hold* etc. in libm that requires exceptions to be discarded and not
trapped on).
Tested for powerpc.
[BZ #19790]
* sysdeps/ieee754/ldbl-128ibm/s_rintl.c [USE_AS_NEARBYINTL]
(rintl): Define as macro.
[USE_AS_NEARBYINTL] (__rintl): Likewise.
(__rintl) [USE_AS_NEARBYINTL]: Use SET_RESTORE_ROUND_NOEX instead
of fesetround. Ensure results are evaluated before end of scope.
* sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c: Define
USE_AS_NEARBYINTL and include s_rintl.c.
* sysdeps/powerpc/fpu/fenv_private.h (libc_feholdsetround_ppc):
Disable exception traps in new environment.
(libc_feholdsetround_ppc_ctx): Likewise.
The GNU libc testsuite fails to build on powerpc/ppc64/ppc64le with the
following error:
../sysdeps/powerpc/test-get_hwcap.c:26:22: fatal error: sys/auxv.h: No such file or director
This is because test-get_hwcap.c includes <sys/auxv.h>, but we don't
provide a wrapper in include/sys. This patch adds one.
Changelog:
* include/sys/auxv.h: New file.
Since x86 has an optimized mempcpy and GCC can inline mempcpy on x86,
define _HAVE_STRING_ARCH_mempcpy to 1 for x86.
[BZ #19759]
* sysdeps/x86/bits/string.h (_HAVE_STRING_ARCH_mempcpy): New.
The operand modifier %s on powerpc is an undocumented internal implementation
detail of GCC. Besides that, the GCC community wants to remove it. This patch
rewrites the expressions that use this modifier with logically equivalent
expressions that don't require it.
Explanation for the substitution:
The %s modifier takes an immediate operand and prints 32 less such immediate.
Thus, in the previous code, the expression resulted in:
32 - __builtin_ffs(e)
where e was guaranteed to have exactly a single bit set, by the following
expressions:
(e & (e-1) == 0) : e has at most one bit set.
(e != 0) : e is not zero, thus it has at least one bit set.
Since we guarantee that there is exactly only one bit set, the following
statement is true:
32 - __builtin_ffs(e) == __builtin_clz(e)
Thus, we can replace __builtin_ffs with __builtin_clz and remove the %s operand
modifier.
