Some distros build+install the timezone tools (zic/zdump/tzselect) outside
of glibc and use the upstream package directly. Add a configure flag to
glibc so they can disable install of those tools.
This allows tests to run & pass regardless of the configure flag. Only
the install of them is impacted.
i386 exp, hypot and pow functions can return overflowing and
underflowing values with excess range and precision; ; Wilco
Dijkstra's patches to make isfinite etc. expand inline cause this
pre-existing issue to result in test failures.
This patch fixes those functions to avoid excess range and precision
in their return values. Appropriate macros are added for the repeated
code sequences; in future I'll add more such macros and refactor
existing code forcing underflow (with or without also eliminating
excess range and precision from the return value) to use such macros.
Tested for x86. If, after this patch, you still see x86 libm test
failures with excess range or precision, please file bugs in Bugzilla.
[BZ #18980]
* sysdeps/i386/fpu/i386-math-asm.h (DEFINE_FLT_MIN): New macro.
(DEFINE_DBL_MIN): Likewise.
(FLT_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise.
(DBL_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise.
(FLT_NARROW_EVAL_UFLOW_NONNEG): Likewise.
(DBL_NARROW_EVAL_UFLOW_NONNEG): Likewise.
* sysdeps/i386/fpu/e_exp.S: Include <i386-math-asm.h>.
(dbl_min): Replace with use of DEFINE_DBL_MIN.
(__ieee754_exp): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN.
(__exp_finite): Use DBL_NARROW_EVAL_UFLOW_NONNEG.
* sysdeps/i386/fpu/e_exp10.S: Include <i386-math-asm.h>.
(dbl_min): Replace with use of DEFINE_DBL_MIN.
(__ieee754_exp10): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN.
* sysdeps/i386/fpu/e_exp10f.S: Include <i386-math-asm.h>.
(flt_min): Replace with use of DEFINE_FLT_MIN.
(__ieee754_exp10f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN.
* sysdeps/i386/fpu/e_exp2.S: Include <i386-math-asm.h>.
(dbl_min): Replace with use of DEFINE_DBL_MIN.
(__ieee754_exp2): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN.
* sysdeps/i386/fpu/e_exp2f.S: Include <i386-math-asm.h>.
(flt_min): Replace with use of DEFINE_FLT_MIN.
(__ieee754_exp2f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN.
* sysdeps/i386/fpu/e_expf.S: Include <i386-math-asm.h>.
(flt_min): Replace with use of DEFINE_FLT_MIN.
(__ieee754_expf): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN.
(__expf_finite): Use FLT_NARROW_EVAL_UFLOW_NONNEG.
* sysdeps/i386/fpu/e_hypot.S: Include <i386-math-asm.h>.
(__ieee754_hypot): Use DBL_NARROW_EVAL.
* sysdeps/i386/fpu/e_hypotf.S: Include <i386-math-asm.h>.
(__ieee754_hypotf): Use FLT_NARROW_EVAL.
* sysdeps/i386/fpu/e_pow.S: Include <i386-math-asm.h>.
(__ieee754_pow): Use DBL_NARROW_EVAL.
* sysdeps/i386/fpu/e_powf.S: Include <i386-math-asm.h>.
(__ieee754_powf): Use FLT_NARROW_EVAL.
* sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S
(__ieee754_expf_sse2): Convert double-precision result to single
precision.
* sysdeps/i386/fpu/libm-test-ulps: Update.
i386 scalb / scalbn / scalbln (and thus ldexp) functions for float and
double can return results with excess range (and consequently excess
precision for subnormal results). As the results of these functions
are fully determined by reference to IEEE 754 operations, this is
unambiguously a bug, apart from the testsuite failures it causes.
This patch makes those functions store their results on the stack and
load them back to eliminate the excess range. Double rounding is not
a problem, as the only cases where it could occur are when the result
overflows or underflows for extended precision, and then the
double-rounded results are the same as the single-rounded results.
The new macros will be used for more functions, more such macros
added, and existing code refactored to use such macros, in subsequent
patches.
Tested for x86. Committed.
[BZ #18981]
* sysdeps/i386/fpu/i386-math-asm.h: New file.
* sysdeps/i386/fpu/e_scalb.S: Include <i386-math-asm.h>.
(__ieee754_scalb): Use DBL_NARROW_EVAL.
* sysdeps/i386/fpu/e_scalbf.S: Include <i386-math-asm.h>.
(__ieee754_scalbf): Use FLT_NARROW_EVAL.
* sysdeps/i386/fpu/s_scalbn.S: Include <i386-math-asm.h>.
(__scalbn): Use DBL_NARROW_EVAL.
* sysdeps/i386/fpu/s_scalbnf.S: Include <i386-math-asm.h>.
(__scalbnf): Use FLT_NARROW_EVAL.
The XT testdata install rules expect the testdata dir to already exist in
the build tree, but it doesn't actually create it. Instead, it relies on
the build-testdata define happening to be executed before it (which runs
zic which creates the dir). When we run in parallel though, it's easy to
hit a failure:
$ cd timezone
$ rm -rf $objdir/timezone/testdata
$ make check -j
...
cp testdata/XT1 .../timezone/testdata/XT1
cp: cannot create regular file '.../timezone/testdata/XT1': No such file or directory
Makefile:116: recipe for target '.../timezone/testdata/XT1' failed
make: *** [.../timezone/testdata/XT1] Error 1
make: *** Waiting for unfinished jobs....
Various i386 libm functions return values with excess range and
precision; Wilco Dijkstra's patches to make isfinite etc. expand
inline cause this pre-existing issue to result in test failures (when
e.g. a result that overflows float but not long double gets counted as
overflowing for some purposes but not others).
This patch addresses those cases arising from functions defined in C,
adding a math_narrow_eval macro that forces values to memory to
eliminate excess precision if FLT_EVAL_METHOD indicates this is
needed, and is a no-op otherwise. I'll convert existing uses of
volatile and asm for this purpose to use the new macro later, once
i386 has clean test results again (which requires fixes for .S files
as well).
Tested for x86_64 and x86. Committed.
[BZ #18980]
* sysdeps/generic/math_private.h: Include <float.h>.
(math_narrow_eval): New macro.
[FLT_EVAL_METHOD != 0] (excess_precision): Likewise.
* sysdeps/ieee754/dbl-64/e_cosh.c (__ieee754_cosh): Use
math_narrow_eval on overflowing return value.
* sysdeps/ieee754/dbl-64/e_lgamma_r.c (__ieee754_lgamma_r):
Likewise.
* sysdeps/ieee754/dbl-64/e_sinh.c (__ieee754_sinh): Likewise.
* sysdeps/ieee754/flt-32/e_coshf.c (__ieee754_coshf): Likewise.
* sysdeps/ieee754/flt-32/e_lgammaf_r.c (__ieee754_lgammaf_r):
Likewise.
* sysdeps/ieee754/flt-32/e_sinhf.c (__ieee754_sinhf): Likewise.
The logic in setjmp/__longjmp incorrectly uses "PIC" to figure out
whether the code is going into a shared library when it should be
using "SHARED". If you build glibc with a gcc version that has PIE
enabled by default, then the code will try to use symbols that are
only in the shared library.
URL: https://bugs.gentoo.org/336914
built-ins when available. Since going through the PLT is expensive for these small functions,
inlining results in major speedups (about 7x on Cortex-A57 for isinf). The GCC built-ins are not
correct if signalling NaN support is required, and thus are turned off in that case (see GCC bug
66462). The test-snan.c tests sNaNs and so must be explicitly built with -fsignaling-nans.
2015-09-18 Wilco Dijkstra <wdijkstr@arm.com>
[BZ #15367]
[BZ #17441]
* math/Makefile: Build test-snan.c with -fsignaling-nans.
* math/math.h (fpclassify): Use __builtin_fpclassify when
available. (signbit): Use __builtin_signbit(f/l).
(isfinite): Use__builtin_isfinite. (isnormal): Use
__builtin_isnormal. (isnan): Use __builtin_isnan.
(isinf): Use __builtin_isinf_sign.
ChangeLog:
2015-09-18 Wilco Dijkstra <wdijkstr@arm.com>
* benchtests/Makefile: Add bench-math-inlines, link with libm.
* benchtests/bench-math-inlines.c: New benchmark.
* benchtests/bench-util.h: New file.
* benchtests/bench-util.c: New file.
* benchtests/bench-skeleton.c: Add include of bench-util.c/h.
The test error messages incorrectly reference LIBC_SO
when they should reference the dlmopen'd library
tst-dlmopen1mod.so. Define TEST_SO and use it in
all the error messages.
Cleanup _dl_map_object_from_fd to make it clear exactly
what we're doing with the mappings i.e. extending the the
start of the map down to a page boundary, extending the
end of the map up to a page boundary, and offset itself
also to page boundary. The result is much easier to read
as expected from the ALIGN_* cleanups.
In ISO 8601, +03:30 is a valid time zone. Currently, strptime() only
parses it as a 2-digit time zone an believes this is +03:00. This change
makes it accept a single colon.
Since we require a new enough kernel all the time, the __ASSUME_FDATASYNC
define has been hardcoded to 1. That means we can delete the alpha file
for fdatasync now and rely on the syscalls list like other ports.
This patch makes linknamespace.pl require weak undefined symbols to be
within the standard namespace. (It remains the case that
linknamespace.pl does not look for definitions of such symbols or
require symbols used in those definitions to be within the standard
namespace.)
Tested for x86_64 and x86.
* conform/linknamespace.pl: Require weak undefined symbols to be
in the standard namespace.
(%strong_syms): Rename to %seen_syms.
(%strong_seen): Rename to %seen_where.
C99/C11 Annex G specifies the sign of the zero part of the result of
ctan (x +/- i * Inf) and ctanh (+/-Inf + i * y). This patch fixes glibc
to follow that specification, along the lines I described in my review
of Andreas's previous patch for this issue
<https://sourceware.org/ml/libc-alpha/2014-08/msg00142.html>.
Tested for x86_64.
2015-09-17 Joseph Myers <joseph@codesourcery.com>
Andreas Schwab <schwab@suse.de>
[BZ #17118]
* math/s_ctan.c (__ctan): Determine sign of zero real part of
result when imaginary part of argument is infinite using sine and
cosine.
* math/s_ctanf.c (__ctanf): Likewise.
* math/s_ctanl.c (__ctanl): Likewise.
* math/s_ctanh.c (__ctanh): Determine sign of zero imaginary part
of result when real part of argument is infinite using sine and
cosine.
* math/s_ctanhf.c (__ctanhf): Likewise.
* math/s_ctanhl.c (__ctanhl): Likewise.
* math/libm-test.inc (ctan_test_data): Add more tests of ctan.
(ctanh_test_data): Add more tests of ctanh.
Bug 15384 notes that in __finite, two different constants are used
that could be the same constant (the result only depends on the
exponent of the floating-point representation), and that using the
same constant is better for architectures where constants need loading
from a constant pool. This patch implements that change.
Tested for x86_64, mips64 and powerpc.
[BZ #15384]
* sysdeps/ieee754/dbl-64/s_finite.c (FINITE): Use same constant as
bit-mask as in subtraction.
* sysdeps/ieee754/dbl-64/wordsize-64/s_finite.c (__finite):
Likewise.
* sysdeps/ieee754/flt-32/s_finitef.c (FINITEF): Likewise.
* sysdeps/ieee754/ldbl-128/s_finitel.c (__finitel): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_finitel.c (__finitel): Likewise.
Similar to various other bugs in this area, tgamma functions can fail
to raise the underflow exception when the result is tiny and inexact
but one or more low bits of the intermediate result that is scaled
down are zero. This patch forces the exception in a similar way to
previous fixes.
Tested for x86_64, x86, mips64 and powerpc.
[BZ #18951]
* sysdeps/ieee754/dbl-64/e_gamma_r.c (__ieee754_gamma_r): Force
underflow exception for small results.
* sysdeps/ieee754/flt-32/e_gammaf_r.c (__ieee754_gammaf_r):
Likewise.
* sysdeps/ieee754/ldbl-128/e_gammal_r.c (__ieee754_gammal_r):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_gammal_r.c (__ieee754_gammal_r):
Likewise.
* sysdeps/ieee754/ldbl-96/e_gammal_r.c (__ieee754_gammal_r):
Likewise.
* math/auto-libm-test-in: Add more tests of tgamma.
* math/auto-libm-test-out: Regenerated.
As noted in bug 6803, scalbn fails to set errno on overflow and
underflow. This patch fixes this by making scalbn an alias of ldexp,
which has exactly the same semantics (for floating-point types with
radix 2) and already has wrappers that deal with setting errno,
instead of an alias of the internal __scalbn (which ldexp calls).
Notes:
* Where compat symbols were defined for scalbn functions, I didn't
change what they point to (to keep the patch minimal), so such
compat symbols continue to go directly to the non-errno-setting
functions.
* Mike, I didn't do anything with the IA64 versions of these
functions, where I think both the ldexp and scalbn functions already
deal with setting errno. As a cleanup (not needed to fix this bug)
however you might want to make those functions into aliases for
IA64; there is no need for them to be separate function
implementations at all.
* This concludes the fix for bug 6803 since the scalb and scalbln
cases of that bug were fixed some time ago.
Tested for x86_64, x86, mips64 and powerpc.
[BZ #6803]
* math/s_ldexp.c (scalbn): Define as weak alias of __ldexp.
[NO_LONG_DOUBLE] (scalbnl): Define as weak alias of __ldexp.
* math/s_ldexpf.c (scalbnf): Define as weak alias of __ldexpf.
* math/s_ldexpl.c (scalbnl): Define as weak alias of __ldexpl.
* sysdeps/i386/fpu/s_scalbn.S (scalbn): Remove alias.
* sysdeps/i386/fpu/s_scalbnf.S (scalbnf): Likewise.
* sysdeps/i386/fpu/s_scalbnl.S (scalbnl): Likewise.
* sysdeps/ieee754/dbl-64/s_scalbn.c (scalbn): Likewise.
[NO_LONG_DOUBLE] (scalbnl): Likewise.
* sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c (scalbn):
Likewise.
[NO_LONG_DOUBLE] (scalbnl): Likewise.
* sysdeps/ieee754/flt-32/s_scalbnf.c (scalbnf): Likewise.
* sysdeps/ieee754/ldbl-128/s_scalbnl.c (scalbnl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_scalbnl.c (scalbnl): Remove
long_double_symbol calls.
* sysdeps/ieee754/ldbl-64-128/s_scalbnl.c (scalbnl): Likewise.
* sysdeps/ieee754/ldbl-opt/s_ldexpl.c (__ldexpl_2): Define as
strong alias of __ldexpl.
(scalbnl): Define using long_double_symbol.
* sysdeps/m68k/m680x0/fpu/s_scalbn.c (__CONCATX(scalbn,suffix)):
Remove alias.
* sysdeps/sparc/sparc64/soft-fp/s_scalbnl.c (scalbnl): Likewise.
* sysdeps/x86_64/fpu/s_scalbnl.S (scalbnl): Likewise.
* math/libm-test.inc (scalbn_test_data): Add errno expectations.
(scalbln_test_data): Add more errno expectations.
This way we do not
need to call the kernel just to get the port. Furthermore, we no
longer increase the reference count on every invocation of
`mach_host_self'.
* mach/mach/mach_traps.h (__mach_host_self, mach_host_self):
Protect declarations against the macro expansion.
* mach/mach_init.c (__mach_host_self_): New variable.
(mach_init): Initialize `__mach_host_self_'.
* mach/mach_init.h (__mach_host_self_): New declaration.
(__mach_host_self, mach_host_self): New macros.
* sysdeps/mach/hurd/dl-sysdep.c (_dl_sysdep_start_cleanup):
Release reference.
The ldbl-128 and ldbl-128ibm expm1l implementations have code to
handle +Inf and finite arguments above an overflow threshold. Since
they now use __expl for large positive arguments to fix other
problems, this code is unreachable; this patch removes it.
Tested for mips64 and powerpc.
[BZ #16415]
* sysdeps/ieee754/ldbl-128/s_expm1l.c (maxlog): Remove variable.
(__expm1l): Remove code to handle positive infinity and overflow.
* sysdeps/ieee754/ldbl-128ibm/s_expm1l.c (maxlog): Remove
variable.
(__expm1l): Remove code to handle positive infinity and overflow.
math.h incorrectly declares various functions for XSI POSIX 2001 and
2008 editions. gamma was removed in the 2001 edition but is still
declared, along with gammaf and gammal which were never standard
functions. isnan is still declared as a function, along with isnanf
and isnanl which were never standard functions, although in 2001 the
function was replaced by the type-generic macro. scalbf and scalbl
are declared although never standard, and scalb was removed in the
2008 edition but is still declared. The scalb type-generic macro in
tgmath.h shouldn't be present for any POSIX version, since POSIX never
had such a type-generic macro.
This patch disables all those declarations in the relevant cases (as a
minimal fix, it leaves them enabled for __USE_MISC). For the matter
of declaring scalb but not scalbf or scalbl for the 2001 edition, a
new macro __MATH_DECLARING_DOUBLE is added, defined by math.h around
includes of bits/mathcalls.h, for bits/mathcalls.h to use to test
which type's functions are being declared.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch).
[BZ #18967]
* math/math.h (__MATH_DECLARING_DOUBLE): New macro. Define and
undefine around includes of <bits/mathcalls.h>.
* math/bits/mathcalls.h [!__USE_MISC && __USE_XOPEN2K] (isnan): Do
not declare function.
[!__USE_MISC && __USE_XOPEN2K] (gamma): Likewise.
[!__USE_MISC && (!__MATH_DECLARING_DOUBLE || __USE_XOPEN2K8)]
(scalb): Likewise.
* math/tgmath.h [!__USE_MISC && __USE_XOPEN_EXTENDED] (scalb): Do
not define macro.
* conform/Makefile (test-xfail-XOPEN2K/math.h/conform): Remove
variable.
(test-xfail-XOPEN2K/tgmath.h/conform): Likewise.
(test-xfail-XOPEN2K8/math.h/conform): Likewise.
(test-xfail-XOPEN2K8/tgmath.h/conform): Likewise.
The ldbl-128ibm implementation of nearbyintl wrongly uses signaling
comparisons such as "if (fabs (u.d[0].d) < TWO52)" on arguments that
might be NaNs, when "invalid" exceptions should not be raised. (For
hard float, this issue may be hidden by
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58684>, powerpc GCC
wrongly only using unordered comparison instructions.) This patch
fixes this by just returning the argument if it is not finite (because
of the arbitrary value of the low part of a NaN in IBM long double,
there are quite a lot of comparisons that could end up involving a NaN
when the argument to nearbyintl is a NaN, so excluding NaN arguments
at the start is the simplest and safest fix).
Tested for powerpc-nofpu, where it removes failures for spurious
"invalid" exceptions from nearbyintl.
[BZ #18857]
* sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c (__nearbyintl): Just
return non-finite argument without doing ordered comparisons on
it.
Bug 16296 notes that fegetround is a pure function and should be
marked as such in fenv.h. This patch implements that.
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by this patch).
[BZ #16296]
* math/fenv.h (fegetround): Use __attribute_pure__.
* include/fenv.h (__fegetround): Likewise.
Similar to various other bugs in this area, ctan and ctanh can fail to
raise the underflow exception for some cases of results that are tiny
and inexact. This patch forces the exception in a similar way to
previous fixes.
Tested for x86_64 and x86.
[BZ #18595]
* math/s_ctan.c (__ctan): Force underflow exception for results
whose real or imaginary part has small absolute value.
* math/s_ctanf.c (__ctanf): Likewise.
* math/s_ctanh.c (__ctanh): Likewise.
* math/s_ctanhf.c (__ctanhf): Likewise.
* math/s_ctanhl.c (__ctanhl): Likewise.
* math/s_ctanl.c (__ctanl): Likewise.
* math/auto-libm-test-in: Do not allow missing underflow for ctan
and ctanh. Add more tests of ctan and ctanh.
Bug 15918 points out that the handling of infinities in hypotf can be
simplified: it's enough to return the absolute value of the infinite
argument without first comparing it to the other argument and possibly
returning that other argument's absolute value. This patch makes that
cleanup (which should not change how hypotf behaves on any input).
Tested for x86_64.
[BZ #15918]
* sysdeps/ieee754/flt-32/e_hypotf.c (__ieee754_hypotf): Simplify
handling of cases where one argument is an infinity.
On i386, the double version of exp10 can miss underflow exceptions if
the result is in the subnormal range for double but the last 11 bits
of the 64-bit extended-precision mantissa happen to be zero. This
patch forces the exception in a similar way to previous fixes.
As with the exp2 and exp fixes, the exp10f changes may in fact not be
needed to ensure underflow exceptions, but are included for
consistency and to fix the exp10 part of bug 18875 by ensuring that
excess range and precision is removed from underflowing return values.
Tested for x86_64 and x86.
[BZ #18875]
[BZ #18966]
* sysdeps/i386/fpu/e_exp10.S (dbl_min): New object.
(MO): New macro.
(__ieee754_exp10): For small results, force underflow exception
and remove excess range and precision from return value.
* sysdeps/i386/fpu/e_exp10f.S (flt_min): New object.
(MO): New macro.
(__ieee754_exp10f): For small results, force underflow exception
and remove excess range and precision from return value.
* math/auto-libm-test-in: Add more tests of exp10.
* math/auto-libm-test-out: Regenerated.
On i386, the double version of exp can miss underflow exceptions if
the result is in the subnormal range for double but the last 11 bits
of the 64-bit extended-precision mantissa happen to be zero. This
patch forces the exception in a similar way to previous fixes.
As with the exp2 fixes, the expf changes may in fact not be needed to
ensure underflow exceptions, but are included for consistency and to
fix the exp part of bug 18875 by ensuring that excess range and
precision is removed from underflowing return values.
Tested for x86_64 and x86.
[BZ #18875]
[BZ #18961]
* sysdeps/i386/fpu/e_exp.S (dbl_min): New object.
(MO): New macro.
(__ieee754_exp): For small results, force underflow exception and
remove excess range and precision from return value.
(__exp_finite): Likewise.
* sysdeps/i386/fpu/e_expf.S (flt_min): New object.
(MO): New macro.
(__ieee754_expf): For small results, force underflow exception and
remove excess range and precision from return value.
(__expf_finite): Likewise.
* math/auto-libm-test-in: Add more tests of exp.
* math/auto-libm-test-out: Regenerated.
Various exp2 implementations in glibc can miss underflow exceptions
when the scaling down part of the calculation is exact (or, in the x86
case, when the conversion from extended precision to the target
precision is exact). This patch forces the exception in a similar way
to previous fixes.
The x86 exp2f changes may in fact not be needed for this purpose -
it's likely to be the case that no argument of type float has an exp2
result so close to an exact subnormal float value that it equals that
value when rounded to 64 bits (even taking account of variation
between different x86 implementations). However, they are included
for consistency with the changes to exp2 and so as to fix the exp2f
part of bug 18875 by ensuring that excess range and precision is
removed from underflowing return values.
Tested for x86_64, x86 and mips64.
[BZ #16521]
[BZ #18875]
* math/e_exp2l.c (__ieee754_exp2l): Force underflow exception for
small results.
* sysdeps/i386/fpu/e_exp2.S (dbl_min): New object.
(MO): New macro.
(__ieee754_exp2): For small results, force underflow exception and
remove excess range and precision from return value.
* sysdeps/i386/fpu/e_exp2f.S (flt_min): New object.
(MO): New macro.
(__ieee754_exp2f): For small results, force underflow exception
and remove excess range and precision from return value.
* sysdeps/i386/fpu/e_exp2l.S (ldbl_min): New object.
(MO): New macro.
(__ieee754_exp2l): Force underflow exception for small results.
* sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Likewise.
* sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Likewise.
* sysdeps/x86_64/fpu/e_exp2l.S (ldbl_min): New object.
(MO): New macro.
(__ieee754_exp2l): Force underflow exception for small results.
* math/auto-libm-test-in: Add more tests or exp2.
* math/auto-libm-test-out: Regenerated.
While doing code review I converted another bespoke round down, and
corrected a comment.
The comment spoke about keeping at least one page allocated even
during systrim, which is not correct. The code does nothing to keep
a page allocated. The code does attempt to keep PAD padding as
documented in comments and MINSIZE as required by design.
Historically in 2002 when Ulrich wrote the code (fa8d436c) the math
was inlined into one statement which did reserve an extra page:
extra = ((top_size - pad - MINSIZE + (pagesz-1)) / pagesz - 1) * pagesz;
There is no reason given for this extra page.
In 2010 Anton Branchard's change (b9b42ee0) from division
to shifts removed the extra page by dropping the "+ (pagesiz-1), which
mean we might have attempted to return -0 via MORECORE. The fix by Will
Newton in 2014 added a check for extra being zero (51a7380b).
From first principles I see no reason why we should keep an extra
page of memory from being trimmed back to the OS. The only sensible
interface is to honour PAD padding as the function is documented,
with the caveat the MINSIZE is maintained for the top chunk.
Given that we've been using this code for 5+ years with no extra
page allocated is sufficient evidence that the comment should be changed
to match the code that I'm touching.
Tested on x86_64 and i686, no regressions.
Consensus in [1] was that the right way to fix this was simply to
redirect from /dev/null to terminate the test if no inputs was found
by the tests own globbing e.g. "*/*.{o,os,oS}.d" This can happen when
the build is incomplete and the tests are started. This failure causes
check-local-headers.sh to hang forever waiting for input from stdin.
This change makes the test terminate immediately if the glob doesn't
return any files.
[1] https://sourceware.org/ml/libc-alpha/2014-12/msg00337.html
