Commit Graph

661 Commits

Author SHA1 Message Date
Joseph Myers
63dbe5f322 Fix j1, jn missing underflows (bug 16559).
Similar to various other bugs in this area, j1 and jn implementations
can fail to raise the underflow exception when the internal
computation is exact although the actual function is inexact.  This
patch forces the exception in a similar way to other such fixes.  (The
ldbl-128 / ldbl-128ibm j1l implementation is different and doesn't
need a change for this until spurious underflows in it are fixed.)

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #16559]
	* sysdeps/ieee754/dbl-64/e_j1.c: Include <float.h>.
	(__ieee754_j1): Force underflow exception for small results.
	* sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Likewise.
	* sysdeps/ieee754/flt-32/e_j1f.c: Include <float.h>.
	(__ieee754_j1f): Force underflow exception for small results.
	* sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise.
	* sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j1l.c: Include <float.h>.
	(__ieee754_j1l): Force underflow exception for small results.
	* sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise.
	* math/auto-libm-test-in: Add more tests of j1 and jn.
	* math/auto-libm-test-out: Regenerated.
2015-06-29 16:52:16 +00:00
Joseph Myers
a8e2112ae3 Use round-to-nearest internally in jn, test with ALL_RM_TEST (bug 18602).
Some existing jn tests, if run in non-default rounding modes, produce
errors above those accepted in glibc, which causes problems for moving
tests of jn to use ALL_RM_TEST.  This patch makes jn set rounding
to-nearest internally, as was done for yn some time ago, then computes
the appropriate underflowing value for results that underflowed to
zero in to-nearest, and moves the tests to ALL_RM_TEST.  It does
nothing about the general inaccuracy of Bessel function
implementations in glibc, though it should make jn more accurate on
average in non-default rounding modes through reduced error
accumulation.  The recomputation of results that underflowed to zero
should as a side-effect fix some cases of bug 16559, where jn just
used an exact zero, but that is *not* the goal of this patch and other
cases of that bug remain unfixed.

(Most of the changes in the patch are reindentation to add new scopes
for SET_RESTORE_ROUND*.)

Tested for x86_64, x86, powerpc and mips64.

	[BZ #16559]
	[BZ #18602]
	* sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Set
	round-to-nearest internally then recompute results that
	underflowed to zero in the original rounding mode.
	* sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise.
	* sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Likewise.
	* sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise
	* math/libm-test.inc (jn_test): Use ALL_RM_TEST.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2015-06-25 21:46:02 +00:00
Joseph Myers
8475ab1684 Fix ldbl-128 expl missing underflows (bug 18586).
Similar to various other bugs in this area, the ldbl-128 expl
implementation does not raise the underflow exception for all
subnormal results, if the scaling down is exact although the actual
result is inexact.  This patch fixes this by forcing the exception in
this case (the tests that failed before and pass after the test are
already in the testsuite).

Tested for mips64.

	[BZ #18586]
	* sysdeps/ieee754/ldbl-128/e_expl.c (__ieee754_expl): Force
	underflow exception for small results.
2015-06-24 15:12:03 +00:00
Joseph Myers
ad39cce0da Fix sin, sincos missing underflows (bug 16526, bug 16538).
Similar to various other bugs in this area, some sin and sincos
implementations do not raise the underflow exception for subnormal
arguments, when the result is tiny and inexact.  This patch forces the
exception in a similar way to previous fixes.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #16526]
	[BZ #16538]
	* sysdeps/ieee754/dbl-64/s_sin.c: Include <float.h>.
	(__sin): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/flt-32/k_sinf.c: Include <float.h>.
	(__kernel_sinf): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/k_sincosl.c: Include <float.h>.
	(__kernel_sincosl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/k_sinl.c: Include <float.h>.
	(__kernel_sinl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/k_sincosl.c: Include <float.h>.
	(__kernel_sincosl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/k_sinl.c: Include <float.h>.
	(__kernel_sinl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/k_sinl.c: Include <float.h>.
	(__kernel_sinl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/powerpc/fpu/k_sinf.c: Include <float.h>.
	(__kernel_sinf): Force underflow exception for arguments with
	small absolute value.
	* math/auto-libm-test-in: Add more tests of sin and sincos.
	* math/auto-libm-test-out: Regenerated.
2015-06-23 22:24:20 +00:00
Joseph Myers
8b1bab5ffa Fix spurious "inexact" exceptions from __kernel_standard_l (bug 18245, bug 18583).
__kernel_standard_l converts long double arguments to double for use
in SVID "struct exception".  This has special-case handling for when
that conversion would overflow or underflow but the original long
double function wouldn't.  However, it turns out that "inexact"
exceptions can be spurious here as well, when the function is exactly
determined and __kernel_standard_l is being called for a domain error.
This patch fixes this by using feholdexcept / fesetenv to avoid
exceptions from the conversion, replacing the previous special-case
logic for overflow and underflow (this covers all functions using
__kernel_standard_l, not just those that actually need a change, since
there doesn't seem to be much point in restricting things just to the
functions that mustn't get "inexact" here).

Tested for x86_64 and x86.

	[BZ #18245]
	[BZ #18583]
	* sysdeps/ieee754/k_standardl.c: Include <fenv.h>.
	(__kernel_standard_l): Use feholdexcept and fesetenv around
	conversion to double instead of special-casing overflow and
	underflow.
	* math/libm-test.inc (fmod_test_data): Add more tests.
	(remainder_test_data): Likewise.
	(sqrt_test_data): Likewise.
2015-06-23 17:26:46 +00:00
Joseph Myers
b59549574e Fix exp2, exp2f spurious underflows (bug 18219).
The dbl-64 and flt-32 implementations of exp2 functions produce
spurious underflow exceptions.  The underlying reason is the same in
both cases: the computation works as (2^a - 1)*2^b + 2^b for suitably
chosen a and b, where a has small magnitude so 2^a - 1 can be computed
with a low-degree polynomial approximation, and (2^a - 1)*2^b can
underflow even when the final result does not.  This patch fixes this
by adjusting the threshold for when scaling is used to avoid
intermediate underflow so it works for any possible value of a where
the final result would not underflow.

Tested for x86_64 and x86.

	[BZ #18219]
	* sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Reduce
	threshold on absolute value of exponent for which scaling is used.
	* sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Likewise.
	* math/auto-libm-test-in: Add more tests of exp2.
	* math/auto-libm-test-out: Regenerated.
2015-06-23 14:35:18 +00:00
Joseph Myers
554edb23ff Fix expm1 missing underflows (bug 16353).
Similar to various other bugs in this area, some expm1 implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.

(The issue does not apply to the ldbl-* implementations or to those
for x86 / x86_64 long double.  The change to
sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c is one I missed when
previously fixing bug 16354; the bug in that implementation was
previously latent, but the expm1 fixes stopped it being latent and so
required it to be fixed to avoid spurious underflows from cosh.)

Tested for x86_64 and x86.

	[BZ #16353]
	* sysdeps/i386/fpu/s_expm1.S (dbl_min): New object.
	(__expm1): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/i386/fpu/s_expm1f.S (flt_min): New object.
	(__expm1f): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/dbl-64/s_expm1.c: Include <float.h>.
	(__expm1): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/flt-32/s_expm1f.c: Include <float.h>.
	(__expm1f): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c (__ieee754_cosh):
	Check for small arguments before calling __expm1.
	* math/auto-libm-test-in: Do not mark underflow exceptions as
	possibly missing for bug 16353.
	* math/auto-libm-test-out: Regenerated.
2015-06-22 21:06:19 +00:00
Andrew Senkevich
c342488200 Fixed powerpc64 build.
* sysdeps/ieee754/ldbl-opt/s_sin.c (__DECL_SIMD_sincos_disable,
    __DECL_SIMD_sincos_disablef, __DECL_SIMD_sincos_disablel): Added empty
    definitions for proper unfolding of __MATHDECL_VEC.
2015-06-19 20:42:34 +03:00
Joseph Myers
8db3cdefef Fix asinh missing underflows (bug 16350).
Similar to various other bugs in this area, some asinh implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.

Tested for x86_64, x86 and mips64.

	[BZ #16350]
	* sysdeps/i386/fpu/s_asinh.S (__asinh): Force underflow exception
	for arguments with small absolute value.
	* sysdeps/i386/fpu/s_asinhf.S (__asinhf): Likewise.
	* sysdeps/i386/fpu/s_asinhl.S (__asinhl): Likewise.
	* sysdeps/ieee754/dbl-64/s_asinh.c: Include <float.h>.
	(__asinh): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/flt-32/s_asinhf.c: Include <float.h>.
	(__asinhf): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-128/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* sysdeps/ieee754/ldbl-96/s_asinhl.c: Include <float.h>.
	(__asinhl): Force underflow exception for arguments with small
	absolute value.
	* math/auto-libm-test-in: Do not mark underflow exceptions as
	possibly missing for bug 16350.
	* math/auto-libm-test-out: Regenerated.
2015-06-18 23:27:41 +00:00
Joseph Myers
2f3184451d Remove ldbl-128ibm variants of complex math functions.
sysdeps/ieee754/ldbl-128ibm has its own versions of cprojl, ctanhl and
ctanl.

Having its own versions, where otherwise the math/ copies are
generally used for all floating-point formats, means they are liable
to get out of sync and not benefit from bug fixes to the generic
versions.  The substantive differences (not arising from getting out
of sync and slightly different fixes for the same issues) are: long
double compat handling (also done in the ldbl-opt versions, so doesn't
require special versions for ldbl-128ibm); handling of LDBL_EPSILON
(conditionally undefined and redefined in other math/ implementations,
so doesn't justify a special version), and:

      /* __gcc_qmul does not respect -0.0 so we need the following fixup.  */
      if ((__real__ res == 0.0L) && (__real__ x == 0.0L))
        __real__ res = __real__ x;

      if ((__real__ res == 0.0L) && (__imag__ x == 0.0L))
        __imag__ res = __imag__ x;

But if that statement about __gcc_qmul was ever true for an old
version of that libgcc function, it's not the case for any GCC version
now supported to build glibc; there's explicit logic early in that
function (and similarly in __gcc_qdiv) to return an appropriately
signed zero if the product of the high parts is zero.  So this patch
adds the special LDBL_EPSILON handling to the generic functions and
removes the ldbl-128ibm versions.

Tested for powerpc32 (compared test-ldouble.out before and after the
changes; there are slight changes to results for ctanl / ctanhl,
arising from divergence of the implementations, but nothing that
affects the overall nature of the issues shown by the testsuite, and
in particular nothing related to signs of zero resutls).

	* math/s_ctanhl.c [LDBL_MANT_DIG == 106] (LDBL_EPSILON): Undefine
	and redefine.
	* math/s_ctanl.c [LDBL_MANT_DIG == 106] (LDBL_EPSILON): Undefine
	and redefine.
	* sysdeps/ieee754/ldbl-128ibm/s_cprojl.c: Remove file.
	* sysdeps/ieee754/ldbl-128ibm/s_ctanhl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_ctanl.c: Likewise.
2015-06-17 21:20:15 +00:00
Wilco Dijkstra
cbf377edd3 Replace finite with isfinite. 2015-06-03 16:35:44 +01:00
Wilco Dijkstra
d81f90ccd0 This patch renames all uses of __isinf*, __isnan*, __finite* and __signbit* to use standard C99 macros. This has no effect on generated code. 2015-06-03 15:41:36 +01:00
Wilco Dijkstra
be2e25bbd7 2015-05-28 Wilco Dijkstra <wdijkstr@arm.com>
* sysdeps/ieee754/dbl-64/s_fabs.c: (__fabs): Call __builtin_fabs.
        * sysdeps/ieee754/flt-32/s_fabsf.c: (__fabsf): Likewise.
2015-05-28 11:42:55 +01:00
Joseph Myers
0c3717e782 Fix ldbl-128 / ldbl-128ibm tanl for -Wuninitialized.
The ldbl-128 and ldbl-128ibm implementations of tanl produce
uninitialized variable warnings with -Wuninitialized because of a
variable that is initialized only conditionally, then used under the
same conditions under which it is set.  This patch uses DIAG_* macros
to suppress those warnings.

Tested for powerpc and mips64.

	* sysdeps/ieee754/ldbl-128/k_tanl.c: Include <libc-internal.h>.
	(__kernel_tanl): Ignore uninitialized warnings around use of SIGN.
	* sysdeps/ieee754/ldbl-128ibm/k_tanl.c: Include <libc-internal.h>.
	(__kernel_tanl): Ignore uninitialized warnings around use of SIGN.
2015-05-22 20:13:44 +00:00
Joseph Myers
31a8780d0b Fix ldbl-128 / ldbl-128ibm erfcl for -Wuninitialized
The ldbl-128 and ldbl-128ibm implementations of erfcl produce
uninitialized variable warnings with -Wuninitialized because of switch
statements where in fact one of the cases will always be executed, but
the compiler does not see that these cases cover all possibilities
(and because the reasoning that it does involves inequalities on the
representation of a floating point value leading to a set of possible
values for 8.0 times that value, converted to int, it's highly
nontrivial for the compiler to see that).  This patch fixes those
warnings by converting the last case in those switch statements to a
"default" case.

Tested for powerpc and mips64.

	* sysdeps/ieee754/ldbl-128/s_erfl.c (__erfcl): Make case 9 in
	switch statement into default case.
	* sysdeps/ieee754/ldbl-128ibm/s_erfl.c (__erfcl): Likewise.
2015-05-22 17:48:45 +00:00
Joseph Myers
fded7ed684 Fix ldbl-128 / ldbl-128ibm asinl for -Wuninitialized.
The ldbl-128 and ldbl-128ibm implementations of asinl produce
uninitialized variable warnings with -Wuninitialized because the code
for small arguments in fact always returns but the compiler cannot see
this and instead sees that a variable would be uninitialized if the
"if (huge + x > one)" conditional used to force the "inexact"
exception were false.

All the code in libm trying to force "inexact" for functions that are
not exactly defined is suspect and should be removed at some point
given that we now have a clear definition of the accuracy goals for
libm functions which, following C99/C11, does not require anything
about "inexact" for most functions (likewise, the multi-precision code
that tries to give correctly-rounded results, very slowly, for
functions for which the goals clearly do not include correct rounding,
if the faster paths are accurate enough).  However, for now this patch
simply changes the code to use math_force_eval, rather than "if", to
ensure the evaluation of the inexact computation.

Tested for powerpc and mips64.

	* sysdeps/ieee754/ldbl-128/e_asinl.c (__ieee754_asinl): Don't use
	a conditional in forcing "inexact".
	* sysdeps/ieee754/ldbl-128ibm/e_asinl.c (__ieee754_asinl):
	Likewise.
2015-05-22 17:36:52 +00:00
Joseph Myers
9124ccf76a Fix lgamma implementations for -Wuninitialized.
If you remove the "override CFLAGS += -Wno-uninitialized" in
math/Makefile, you get errors from lgamma implementations of the form:

../sysdeps/ieee754/dbl-64/e_lgamma_r.c: In function '__ieee754_lgamma_r':
../sysdeps/ieee754/dbl-64/e_lgamma_r.c:297:13: error: 'nadj' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  if(hx<0) r = nadj - r;

This is one of the standard kinds of false positive uninitialized
warnings: nadj is set under a certain condition, and then later used
under the same condition.  This patch uses DIAG_* macros to suppress
the warning on the use of nadj.  The ldbl-128 / ldbl-128ibm
implementation has a substantially different structure that avoids
this issue.

Tested for x86_64.  (In fact this patch eliminates the need for that
-Wno-uninitialized on x86_64, but I want to test on more architectures
before removing it.)

	* sysdeps/ieee754/dbl-64/e_lgamma_r.c: Include <libc-internal.h>.
	(__ieee754_lgamma_r): Ignore uninitialized warnings around use of
	NADJ.
	* sysdeps/ieee754/flt-32/e_lgammaf_r.c: Include <libc-internal.h>.
	(__ieee754_lgammaf_r): Ignore uninitialized warnings around use of
	NADJ.
	* sysdeps/ieee754/ldbl-96/e_lgammal_r.c: Include <libc-internal.h>.
	(__ieee754_lgammal_r): Ignore uninitialized warnings around use of
	NADJ.
2015-05-21 23:44:33 +00:00
Joseph Myers
89f3b6e18c Fix sysdeps/ieee754/dbl-64/mpa.c for -Wuninitialized.
If you remove the "override CFLAGS += -Wno-uninitialized" in
math/Makefile, one of the errors you get is:

../sysdeps/ieee754/dbl-64/mpa.c: In function '__mp_dbl.part.0':
../sysdeps/ieee754/dbl-64/mpa.c:183:5: error: 'c' may be used uninitialized in this function [-Werror=maybe-uninitialized]
   c *= X[0];

The problem is that the p < 5 case initializes c if p is 1, 2, 3 or 4
but not otherwise, and in fact p is positive for all calls to this
function so the uninitialized case can't actually occur.  This patch
replaces the "if (p == 4)" last case with a comment so the compiler
can see that all paths do initialize c.

Tested for x86_64.

	* sysdeps/ieee754/dbl-64/mpa.c (norm): Remove if condition on
	(p == 4) case.
2015-05-21 23:05:45 +00:00
Joseph Myers
3ce2232efb Fix ldbl-96 remquol (finite, Inf) (bug 18244).
ldbl-96 remquol wrongly handles the case where the first argument is
finite and the second infinite, because the check for the second
argument being a NaN fails to disregard the explicit high mantissa bit
and so wrongly interprets an infinity as being a NaN.  This patch
fixes this by masking off that bit, and improves test coverage for
both remainder and remquo (various cases were missing tests, or, as in
the case of the bug, were tested only for one of the two functions).

Tested for x86_64 and x86.

	[BZ #18244]
	* sysdeps/ieee754/ldbl-96/s_remquol.c (__remquol): Ignore explicit
	high mantissa bit when testing whether P is a NaN.
	* math/libm-test.inc (remainder_test_data): Add more tests.
	(remquo_test_data): Likewise.
2015-05-19 23:44:28 +00:00
Joseph Myers
8020a80887 Fix atanhl missing underflows (bug 16352).
Similar to various other bugs in this area, some atanh implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.  (No change in this regard is needed
for the i386 implementation; special handling to force underflows in
these cases will only be needed there when the spurious underflows,
bug 18049, get fixed.)

Tested for x86_64, x86, powerpc and mips64.

	[BZ #16352]
	* sysdeps/i386/fpu/e_atanh.S (dbl_min): New object.
	(__ieee754_atanh): Force underflow exception for results with
	small absolute value.
	* sysdeps/i386/fpu/e_atanhf.S (flt_min): New object.
	(__ieee754_atanhf): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/dbl-64/e_atanh.c: Include <float.h>.
	(__ieee754_atanh): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/flt-32/e_atanhf.c: Include <float.h>.
	(__ieee754_atanhf): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/e_atanhl.c: Include <float.h>.
	(__ieee754_atanhl): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/e_atanhl.c: Include <float.h>.
	(__ieee754_atanhl): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/e_atanhl.c: Include <float.h>.
	(__ieee754_atanhl): Force underflow exception for results with
	small absolute value.
	* math/auto-libm-test-in: Do not allow missing underflow
	exceptions from atanh.
	* math/auto-libm-test-out: Regenerated.
2015-05-15 22:07:57 +00:00
Joseph Myers
5a608ccc2d Fix tanf spurious underflows (bug 18221).
The flt-32 implementation of tanf produces spurious underflow
exceptions for some small arguments, through computing values on the
order of x^5.  This patch fixes this by adjusting the threshold for
returning x (or, as applicable, +/- 1/x) to 2**-13 (the next term in
the power series being x^3/3).

Tested for x86_64 and x86.

	[BZ #18221]
	* sysdeps/ieee754/flt-32/k_tanf.c (__kernel_tanf): Use 2**-13 not
	2**-28 as threshold for returning x or +/- 1/x.
	* math/auto-libm-test-in: Add more tests of tan.
	* math/auto-libm-test-out: Regenerated.
2015-05-15 17:47:29 +00:00
Joseph Myers
ff069f024a Fix lgammaf spurious underflows (bug 18220).
The flt-32 implementation of lgammaf produces spurious underflow
exceptions for some large arguments, because of calculations involving
x^-2 multiplied by small constants.  This patch fixes this by
adjusting the threshold for a simpler computation to 2**26 (the error
in the simpler computation is on the order of 0.5 * log (x), for a
result on the order of x * log (x)).

Tested for x86_64 and x86.

	[BZ #18220]
	* sysdeps/ieee754/flt-32/e_lgammaf_r.c (__ieee754_lgammaf_r): Use
	2**26 not 2**58 as threshold for returning x * (log (x) - 1).
	* math/auto-libm-test-in: Add another test of lgamma.
	* math/auto-libm-test-out: Regenerated.
2015-05-15 17:21:08 +00:00
Wilco Dijkstra
0e9be4db8f Remove various ABS macros and replace uses with fabs (or in one case abs)
which is more efficient on all targets.
2015-05-15 11:04:40 +00:00
Joseph Myers
fbc68f03b0 Fix erfcf spurious underflows (bug 18217).
The flt-32 implementation of erfcf produces spurious underflow
exceptions for some arguments close to 0, because of calculations
squaring the argument and then multiplying by small constants.  This
patch fixes this by adjusting the threshold for arguments for which
the result is so close to 1 that 1 - x will give the right result from
2**-56 to 2**-26.  (If 1 - x * 2/sqrt(pi) were used, the errors would be
on the order of x^3 and a much larger threshold could be used.)

Tested for x86_64 and x86.

	[BZ #18217]
	* sysdeps/ieee754/flt-32/s_erff.c (__erfcf): Use 2**-26 not 2**-56
	as threshold for returning 1 - x.
	* math/auto-libm-test-in: Add more tests of erfc.
	* math/auto-libm-test-out: Regenerated.
2015-05-15 00:16:10 +00:00
Joseph Myers
9a71f1fcf5 Fix atanf spurious underflows (bug 18196).
The sysdeps/ieee754/flt-32 version of atanf produces spurious
underflow exceptions for some large arguments, because of computations
that compute x^-4.  This patch fixes this by adjusting the threshold
for large arguments (for which +/- pi/2 can just be returned, the
correct result being roughly +/- pi/2 - 1/x) from 2^34 to 2^25.

Tested for x86_64 and x86.

	[BZ #18196]
	* sysdeps/ieee754/flt-32/s_atanf.c (__atanf): Use 2^25 not 2^34 as
	threshold for large arguments.
	* math/auto-libm-test-in: Add another test of atan.
	* math/auto-libm-test-out: Regenerated.
2015-05-14 23:51:09 +00:00
Joseph Myers
0b7a5f9201 Fix log1p missing underflows (bug 16339).
Similar to various other bugs in this area, some log1p implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.  (The ldbl-128ibm implementation
doesn't currently need any change as it already generates this
exception, albeit through code that would generate spurious exceptions
in other cases; special code for this issue will only be needed there
when fixing the spurious exceptions.)

Tested for x86_64, x86, powerpc and mips64.

	[BZ #16339]
	* sysdeps/i386/fpu/s_log1p.S (dbl_min): New object.
	(__log1p): Force underflow exception for results with small
	absolute value.
	* sysdeps/i386/fpu/s_log1pf.S (flt_min): New object.
	(__log1pf): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/dbl-64/s_log1p.c: Include <float.h>.
	(__log1p): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/flt-32/s_log1pf.c: Include <float.h>.
	(__log1pf): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/ldbl-128/s_log1pl.c: Include <float.h>.
	(__log1pl): Force underflow exception for results with small
	absolute value.
	* math/auto-libm-test-in: Do not allow missing underflow
	exceptions from log1p.
	* math/auto-libm-test-out: Regenerated.
2015-05-14 23:38:07 +00:00
Joseph Myers
7d0b257541 Fix ldbl-128 roundl for exponents in [31, 47] (bug 18346).
The implementation of roundl for ldbl-128 involves undefined behavior
for arguments with exponents from 31 to 47 inclusive, from the shift:

      u_int64_t i = -1ULL >> (j0 - 48);

For example, on mips64, this means roundl (0xffffffffffff.8p0L)
wrongly returns its argument, which is not an integer.  A condition
checking for exponents < 31 should actually be checking for exponents
< 48, and this patch makes it do so.  (That condition is for whether
the bit representing 0.5 is in the high 64-bit half of the
floating-point number.  The value 31 might have arisen from an
incorrect conversion of the ldbl-96 version to handle ldbl-128.)

This was originally reported as a GCC libquadmath bug
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65757>.

Tested for mips64; also tested for x86_64 and x86 to make sure the new
tests pass there.

	[BZ #18346]
	* sysdeps/ieee754/ldbl-128/s_roundl.c (__roundl): Handle all
	exponents less than 48 as cases where high part of mantissa needs
	examining to determine whether argument is integral.
	* math/libm-test.inc (round_test_data): Add more tests.
2015-04-28 17:27:02 +00:00
Wilco Dijkstra
92f2897953 Use __copysign rather than copysign. 2015-04-22 12:07:56 +00:00
Stefan Liebler
de8aadd52c Set errno for log1p on pole/domain error.
According to bug 6792, errno is not set to ERANGE/EDOM
by calling log1p/log1pf/log1pl with x = -1 or x < -1.

This patch adds a wrapper which sets errno in those cases
and returns the value of the existing __log1p function.
The log1p is now an alias to the wrapper function
instead of __log1p.

The files in sysdeps are reflecting these changes.
The ia64 implementation sets errno by itself,
thus the wrapper-file is empty.

The libm-test is adjusted for log1p-tests to check errno.

	[BZ #6792]
	* math/w_log1p.c: New file.
	* math/w_log1pf.c: Likewise.
	* math/w_log1pl.c: Likewise.
	* math/Makefile (libm-calls): Add w_log1p.
	* math/s_log1pl.c (log1pl): Remove weak_alias.
	* sysdeps/i386/fpu/s_log1p.S (log1p): Likewise.
	* sysdeps/i386/fpu/s_log1pf.S (log1pf): Likewise.
	* sysdeps/i386/fpu/s_log1pl.S (log1pl): Likewise.
	* sysdeps/x86_64/fpu/s_log1pl.S (log1pl): Likewise.
	* sysdeps/ieee754/dbl-64/s_log1p.c (log1p): Likewise.
	[NO_LONG_DOUBLE] (log1pl): Likewise.
	* sysdeps/ieee754/flt-32/s_log1pf.c (log1pf): Likewise.
	* sysdeps/ieee754/ldbl-128/s_log1pl.c (log1pl): Likewise.
	* sysdeps/ieee754/ldbl-64-128/s_log1pl.c
	(log1p): Remove long_double_symbol.
	* sysdeps/ieee754/ldbl-128ibm/s_log1pl.c (log1pl): Likewise.
	* sysdeps/ieee754/ldbl-64-128/w_log1pl.c: New file.
	* sysdeps/ieee754/ldbl-128ibm/w_log1pl.c: Likewise.
	* sysdeps/m68k/m680x0/fpu/s_log1p.c: Define empty weak_alias to
	remove weak_alias for corresponding log1p function.
	* sysdeps/m68k/m680x0/fpu/s_log1pf.c: Likewise.
	* sysdeps/m68k/m680x0/fpu/s_log1pl.c: Likewise.
	* sysdeps/ia64/fpu/w_log1p.c: New file.
	* sysdeps/ia64/fpu/w_log1pf.c: Likewise.
	* sysdeps/ia64/fpu/w_log1pl.c: Likewise.
	* math/libm-test.inc (log1p_test_data):	Add errno expectations.
2015-04-13 21:19:27 +02:00
Joseph Myers
8431838dde Fix dbl-64 atan2 in non-default rounding modes (bug 18210, bug 18211).
The dbl-64 implementation of atan2 does computations that expect to
run in round-to-nearest mode, and in other modes the errors can
accumulate to more than the maximum accepted 9ulp.  This patch makes
it use FE_TONEAREST internally, similar to other functions with such
issues.  Tests that previously produced large errors are added for
atan2 and the closely related carg, clog and clog10 functions.

Tested for x86_64 and x86 and ulps updated accordingly.

	[BZ #18210]
	[BZ #18211]
	* sysdeps/ieee754/dbl-64/e_atan2.c: Include <fenv.h>.
	(__ieee754_atan2): Set FE_TONEAREST mode for internal
	computations.
	* math/auto-libm-test-in: Add more tests of atan2, carg, clog and
	clog10.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2015-04-08 17:32:17 +00:00
Joseph Myers
ae63c7ebed Fix dbl-64 atan in non-default rounding modes (bug 18197).
The dbl-64 implementation of atan does computations that expect to run
in round-to-nearest mode, and in other modes the errors can accumulate
to more than the maximum accepted 9ulp.  This patch makes it use
FE_TONEAREST internally, similar to other functions with such issues.

Tested for x86_64 and x86; no ulps updates needed.

	[BZ #18197]
	* sysdeps/ieee754/dbl-64/s_atan.c: Include <fenv.h>.
	(atan): Set FE_TONEAREST mode for internal computations.
	* math/auto-libm-test-in: Add more tests of atan.
	* math/auto-libm-test-out: Regenerated.
2015-04-08 17:14:12 +00:00
Adhemerval Zanella
d421868bb8 powerpc: Fix incorrect results for pow when using FMA
This patch adds no FMA generation for e_pow to avoid precision issues
for powerpc.  This fixes BZ#18104.
2015-03-10 09:38:54 -04:00
Joseph Myers
2ca725c594 Fix ldbl-96, ldbl-128ibm atanhl inaccuracy (bug 18046, bug 18047).
The threshold in ldbl-96 atanhl for when to return the argument,
0x1p-28, is a bit too big, and that in ldbl-128ibm atanhl is much too
big (the relevant condition being x^3/3 being < 0.5ulp of x),
resulting in errors a bit above the limits of those considered
acceptable in glibc in the ldbl-96 case, and in large errors in the
ldbl-128ibm case.  This patch changes those implementations to use
more appropriate thresholds and adds tests around the thresholds for
various formats.

Tested for x86_64, x86 and powerpc.  x86_64 and x86 ulps updated
accordingly.

	[BZ #18046]
	[BZ #18047]
	* sysdeps/ieee754/ldbl-128ibm/e_atanhl.c (__ieee754_atanhl): Use
	0x1p-56L as threshold for just returning the argument.
	* sysdeps/ieee754/ldbl-96/e_atanhl.c (__ieee754_atanhl): Use
	0x1p-32L as threshold for just returning the argument.
	* math/auto-libm-test-in: Add more tests of atanh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulp: Likewise.
2015-02-27 17:48:37 +00:00
Joseph Myers
f8ab5d38fd Add comment to CSTR macro in k_standard.c.
* sysdeps/ieee754/k_standard.c (CSTR): Add comment.
2015-02-27 01:12:19 +00:00
Joseph Myers
31331a07a5 Avoid -Wno-write-strings for k_standard.c.
We want to avoid -Wno- options in makefiles as far as possible, by
cleaning up the underlying issues if possible or failing that by using
diagnostic pragmas.  This patch eliminates the use of
-Wno-write-strings for sysdeps/ieee754/k_standard.c by using casts in
the source file to cast away const; those casts are encapsulated in a
macro that also deals with the choice of strings for float / double /
long double functions (for which the logic was previously replicated
many times).

Tested for x86_64; the only change to disassembly of installed
stripped shared libraries was a line number in an assertion.

	* sysdeps/ieee754/k_standard.c (CSTR): New macro.
	(__kernel_standard): Use CSTR macro when setting exc.name.
	* sysdeps/ieee754/Makefile [$(subdir) = math]
	(CFLAGS-k_standard.c): Remove variable.
2015-02-26 22:50:54 +00:00
Joseph Myers
09220e6634 Avoid uninitialized warnings in Bessel functions.
math/Makefile currently has:

  # The fdlibm code generates a lot of these warnings but is otherwise clean.
  override CFLAGS += -Wno-uninitialized

This is of course undesirable; warnings should be disabled as narrowly
as possible.  To remove this override, we need to fix files that
generate such warnings, or put warning-disabling pragmas in them.
This patch does so for Bessel function implementations, one of the
cases that have the warnings if the override is removed.  The warnings
arise because functions set pointer variables p and q only for certain
values of the function argument, then use them unconditionally.  As
the static functions in question only get called for arguments that
satisfy the last condition in the if/else chain, the natural fix is to
change the last "else if" to just "else", which this patch does.  (The
ldbl-128 / ldbl-128ibm implementation of these functions is
substantially different and looks like it already does use "else" in
the last case in the nearest corresponding code.)

Tested for x86_64 and x86.

	* sysdeps/ieee754/dbl-64/e_j0.c (pzero): Change last case for
	setting p and q from "else if" to "else".
	(qzero): Likewise.
	* sysdeps/ieee754/dbl-64/e_j1.c (pone): Likewise.
	(qone): Likewise.
	* sysdeps/ieee754/flt-32/e_j0f.c (pzerof): Likewise.
	(qzerof): Likewise.
	* sysdeps/ieee754/flt-32/e_j1f.c (ponef): Likewise.
	(qonef): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j0l.c (pzero): Likewise.
	(qzero): Likewise.
	* sysdeps/ieee754/ldbl-96/e_j1l.c (pone): Likewise.
	(qone): Likewise.
2015-02-26 21:49:19 +00:00
Joseph Myers
1d9ab20c14 Fix ldbl-128/ldbl-128ibm acosl inaccuracy (bug 18038, bug 18039).
The ldbl-128 and ldbl-128ibm implementations of acosl have similar
bugs, using a threshold of 0x1p-57L to determine when they just return
pi/2.  Since the result pi/2 - asinl (x) is roughly pi/2 - x for small
x, the relevant cut-off is actually x being < 0.5ulp of 1.  This patch
fixes the implementations to use that cut-off and adds tests of small
acos arguments.

Tested for powerpc and mips64.  Also tested for x86_64 and x86; no
ulps updates needed.

	[BZ #18038]
	[BZ #18039]
	* sysdeps/ieee754/ldbl-128/e_acosl.c (__ieee754_acosl): Only
	return pi/2 for arguments below 0x1p-113L.
	* sysdeps/ieee754/ldbl-128ibm/e_acosl.c (__ieee754_acosl): Only
	return pi/2 for arguments below 0x1p-106L.
	* math/auto-libm-test-in: Add more tests of acos.
	* math/auto-libm-test-out: Regenerated.
2015-02-26 21:06:34 +00:00
Joseph Myers
ec0ce0d3be Fix asin missing underflows (bug 16351).
Similar to various other bugs in this area, some asin implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.

Tested for x86_64, x86, powerpc and mips64.

	[BZ #16351]
	* sysdeps/i386/fpu/e_asin.S (dbl_min): New object.
	(MO): New macro.
	(__ieee754_asin): Force underflow exception for results with small
	absolute value.
	* sysdeps/i386/fpu/e_asinf.S (flt_min): New object.
	(MO): New macro.
	(__ieee754_asinf): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/dbl-64/e_asin.c: Include <float.h> and <math.h>.
	(__ieee754_asin): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/flt-32/e_asinf.c: Include <float.h>.
	(__ieee754_asinf): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/e_asinl.c: Include <float.h>.
	(__ieee754_asinl): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/e_asinl.c: Include <float.h>.
	(__ieee754_asinl): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/e_asinl.c: Include <float.h>.
	(__ieee754_asinl): Force underflow exception for results with
	small absolute value.
	* sysdeps/x86_64/fpu/multiarch/e_asin.c [HAVE_FMA4_SUPPORT]:
	Include <math.h>.
	* math/auto-libm-test-in: Do not mark underflow exceptions as
	possibly missing for bug 16351.
	* math/auto-libm-test-out: Regenerated.
2015-02-26 17:18:54 +00:00
Joseph Myers
380bd0fd24 Fix ldbl-128ibm logbl near powers of 2 (bug 18030).
The ldbl-128ibm implementation of logbl produces incorrect results
when the high part of the argument is a power of 2 and the low part a
nonzero number with the opposite sign (and so the returned exponent
should be 1 less than that of the high part).  For example, logbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1.  (This is
similar to (fixed) bug 16740 for frexpl, and (fixed) bug 18029 for
ilogbl.)  This patch adds checks for that case.

Tested for powerpc.

	[BZ #18030]
	* sysdeps/ieee754/ldbl-128ibm/s_logbl.c (__logbl): Adjust exponent
	of power of 2 down when low part has opposite sign.
	* math/libm-test.inc (logb_test_data): Add more tests.
2015-02-26 15:14:58 +00:00
Joseph Myers
524ae9ea2e Fix ldbl-128ibm ilogbl near powers of 2 (bug 18029).
The ldbl-128ibm implementation of ilogbl produces incorrect results
when the high part of the argument is a power of 2 and the low part a
nonzero number with the opposite sign (and so the returned exponent
should be 1 less than that of the high part).  For example, ilogbl
(0x1.ffffffffffffffp1L) returns 2 but should return 1.  (This is
similar to (fixed) bug 16740 for frexpl, and bug 18030 for logbl.)
This patch adds checks for that case.

Tested for powerpc.

	[BZ #18029]
	* sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c (__ieee754_ilogbl):
	Adjust exponent of power of 2 down when low part has opposite
	sign.
	* math/libm-test.inc (ilogb_test_data): Add more tests.
2015-02-26 12:57:21 +00:00
Joseph Myers
137cef7d43 Fix ldbl-128ibm asinhl inaccuracy (bug 18020).
The ldbl-128ibm implementation of asinhl uses cut-offs of 0x1p28 and
0x1p-29 to determine when to use simpler formulas that avoid possible
overflow / underflow.  Both those cut-offs are inappropriate for this
format, resulting in large errors.  This patch changes the code to use
more appropriate cut-offs of 0x1p56 and 0x1p-56, adding tests around
the cut-offs for various floating-point formats.

Tested for powerpc.  Also tested for x86_64 and x86 and updated ulps.

	[BZ #18020]
	* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Use 2**56 and
	2**-56 not 2**28 and 2**-29 as thresholds for simpler formulas.
	* math/auto-libm-test-in: Add more tests of asinh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2015-02-25 11:13:41 +00:00
Joseph Myers
440169d681 Fix ldbl-128ibm acoshl inaccuracy (bug 18019).
The ldbl-128ibm implementation of acoshl uses a cut-off of 0x1p28 to
determine when to use log(x) + log(2) as a formula.  That cut-off is
too small for this format, resulting in large errors.  This patch
changes it to a more appropriate cut-off of 0x1p56, adding tests
around the cut-offs for various floating-point formats.

Tested for powerpc.  Also tested for x86_64 and x86 and updated ulps.

	[BZ #18019]
	* sysdeps/ieee754/ldbl-128ibm/e_acoshl.c (__ieee754_acoshl): Use
	2**56 not 2**28 as threshold for log (2x) formula.
	* math/auto-libm-test-in: Add more tests of acosh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2015-02-25 00:01:15 +00:00
Joseph Myers
4629c866ad Fix atan / atan2 missing underflows (bug 15319).
This patch fixes bug 15319, missing underflows from atan / atan2 when
the result of atan is very close to its small argument (or that of
atan2 is very close to the ratio of its arguments, which may be an
exact division).

The usual approach of doing an underflowing computation if the
computed result is subnormal is followed.  For 32-bit x86, there are
extra complications: the inline __ieee754_atan2 in bits/mathinline.h
needs to be disabled for float and double because other libm functions
using it generally rely on getting proper underflow exceptions from
it, while the out-of-line functions have to remove excess range and
precision from the underflowing result so as to return an exact 0 in
the case where errno should be set for underflow to 0.  (The failures
I saw without that are similar to those Carlos reported for other
functions, where I haven't seen a response to
<https://sourceware.org/ml/libc-alpha/2015-01/msg00485.html>
confirming if my diagnosis is correct.  Arguably all libm functions
with float and double returns should remove excess range and
precision, but that's a separate matter.)

The x86_64 long double case reported in a comment in bug 15319 is not
a bug (it's an argument of LDBL_MIN, and x86_64 is an after-rounding
architecture so the correct IEEE result is not to raise underflow in
the given rounding mode, in addition to treating the result as an
exact LDBL_MIN being within the newly clarified documentation of
accuracy goals).  I'm presuming that the fpatan instruction can be
trusted to raise appropriate exceptions when the (long double) result
underflows (after rounding) and so no changes are needed for x86 /
x86_64 long double functions here; empirically this is the case for
the cases covered in the testsuite, on my system.

Tested for x86_64, x86, powerpc and mips64.  Only 32-bit x86 needs
ulps updates (for the changes to inlines meaning some functions no
longer get excess precision from their __ieee754_atan2* calls).

	[BZ #15319]
	* sysdeps/i386/fpu/e_atan2.S (dbl_min): New object.
	(MO): New macro.
	(__ieee754_atan2): For results with small absolute value, force
	underflow exception and remove excess range and precision from
	return value.
	* sysdeps/i386/fpu/e_atan2f.S (flt_min): New object.
	(MO): New macro.
	(__ieee754_atan2f): For results with small absolute value, force
	underflow exception and remove excess range and precision from
	return value.
	* sysdeps/i386/fpu/s_atan.S (dbl_min): New object.
	(MO): New macro.
	(__atan): For results with small absolute value, force underflow
	exception and remove excess range and precision from return value.
	* sysdeps/i386/fpu/s_atanf.S (flt_min): New object.
	(MO): New macro.
	(__atanf): For results with small absolute value, force underflow
	exception and remove excess range and precision from return value.
	* sysdeps/ieee754/dbl-64/e_atan2.c: Include <float.h> and
	<math.h>.
	(__ieee754_atan2): Force underflow exception for results with
	small absolute value.
	* sysdeps/ieee754/dbl-64/s_atan.c: Include <float.h> and
	<math_private.h>.
	(atan): Force underflow exception for results with small absolute
	value.
	* sysdeps/ieee754/flt-32/s_atanf.c: Include <float.h>.
	(__atanf): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/ldbl-128/s_atanl.c: Include <float.h> and
	<math.h>.
	(__atanl): Force underflow exception for results with small
	absolute value.
	* sysdeps/ieee754/ldbl-128ibm/s_atanl.c: Include <float.h>.
	(__atanl): Force underflow exception for results with small
	absolute value.
	* sysdeps/x86/fpu/bits/mathinline.h
	[!__SSE2_MATH__ && !__x86_64__ && __LIBC_INTERNAL_MATH_INLINES]
	(__ieee754_atan2): Only define inline for long double.
	* sysdeps/x86_64/fpu/multiarch/e_atan2.c
	[HAVE_FMA4_SUPPORT || HAVE_AVX_SUPPORT]: Include <math.h>.
	* math/auto-libm-test-in: Do not mark underflow exceptions as
	possibly missing for bug 15319.  Add more tests of atan2.
	* math/auto-libm-test-out: Regenerated.
	* math/libm-test.inc (casin_test_data): Do not mark underflow
	exceptions as possibly missing for bug 15319.
	(casinh_test_data): Likewise.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
2015-02-18 21:10:49 +00:00
Joseph Myers
ce8fc784e6 Fix sign of remquo zero remainder in round-downward mode (bug 17987).
Various remquo implementations produce a zero remainder with the wrong
sign (a zero remainder should always have the sign of the first
argument, as specified in IEEE 754) in round-downward mode, resulting
from the sign of 0 - 0.  This patch checks for zero results and fixes
their sign accordingly.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #17987]
	* sysdeps/ieee754/dbl-64/s_remquo.c (__remquo): Ensure sign of
	zero result does not depend on the sign resulting from
	subtraction.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo):
	Likewise.
	* sysdeps/ieee754/flt-32/s_remquof.c (__remquof): Likewise.
	* sysdeps/ieee754/ldbl-128/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-96/s_remquol.c (__remquol): Likewise.
	* math/libm-test.inc (remquo_test_data): Add more tests.
2015-02-17 00:41:50 +00:00
Joseph Myers
a820f9b3c0 Fix remquo spurious overflows (bug 17978).
Various remquo implementations, when computing the last three bits of
the quotient, have spurious overflows when 4 times the second argument
to remquo overflows.  These overflows can in turn cause bad results in
rounding modes where that overflow results in a finite value.  This
patch adds tests to avoid the problem multiplications in cases where
they would overflow, similar to those that control an earlier
multiplication by 8.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #17978]
	* sysdeps/ieee754/dbl-64/s_remquo.c (__remquo): Do not form
	products 4 * y and 2 * y where those would overflow.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo):
	Likewise.
	* sysdeps/ieee754/flt-32/s_remquof.c (__remquof): Likewise.
	* sysdeps/ieee754/ldbl-128/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise.
	* sysdeps/ieee754/ldbl-96/s_remquol.c (__remquol): Likewise.
	* math/libm-test.inc (remquo_test_data): Add more tests.
2015-02-16 22:38:28 +00:00
Joseph Myers
d9afe48d55 Fix dbl-64/wordsize-64 remquo (bug 17569).
The dbl-64/wordsize-64 remquo implementation follows similar logic to
various other implementations, but where that logic computes some
absolute values, it wrongly uses a previously computed bit-pattern for
the absolute value of the first argument, where actually it needs the
absolute value of the first argument mod 8 times the second.  This
patch fixes it to compute the correct absolute value.

The integer quotient result of remquo is only specified mod 8
(including its sign); architecture-specific versions may well vary in
what results they give for higher bits of that result (and indeed bug
17569 gives an example correct result from __builtin_remquo giving 9
for that result, where the particular glibc implementation used in
that bug report would give 1 after this fix).  Thus, this patch adapts
the tests of remquo to test that result only mod 8, to allow for such
variation when tests with higher quotient are included.

Tested for x86_64 and x86.

	[BZ #17569]
	* sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo):
	Compute absolute value of x as modified by fmod, not original
	value of x.
	* math/libm-test.inc (RUN_TEST_ffI_f1): Rename to
	RUN_TEST_ffI_f1_mod8.  Check extra return value mod 8.
	(RUN_TEST_LOOP_ffI_f1): Rename to RUN_TEST_LOOP_ffI_f1_mod8.  Call
	RUN_TEST_ffI_f1_mod8.
	(remquo_test_data): Add more tests.
2015-02-13 21:54:44 +00:00
Joseph Myers
03d95bd483 Fix exp2 spurious underflows (bug 16560).
This patch fixes the remaining part of bug 16560, spurious underflows
from exp2 of arguments close to 0 (when the result is close to 1, so
should not underflow), by just using 1+x instead of a more complicated
calculation when the argument is sufficiently small.

Tested for x86_64, x86 and mips64.

	[BZ #16560]
	* math/e_exp2l.c [LDBL_MANT_DIG == 106] (LDBL_EPSILON): Undefine
	and redefine.
	(__ieee754_exp2l): Do not multiply small fractional parts by
	M_LN2l.
	* sysdeps/i386/fpu/e_exp2l.S (__ieee754_exp2l): Just add 1 to
	small argument.
	* 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 (__ieee754_exp2l): Likewise.
	* math/auto-libm-test-in: Add more tests of exp2.
	* math/auto-libm-test-out: Regenerated.
2015-02-12 19:02:45 +00:00
Joseph Myers
d435569cd6 Fix sincos errno setting (bug 15467).
This patch makes sincos set errno to EDOM when passed an infinity,
similarly to sin and cos.

Tested for x86_64, x86, powerpc and mips64.  I don't know if the
architecture-specific implementations for ia64 and m68k might need
corresponding fixes.

2015-02-11  Joseph Myers  <joseph@codesourcery.com>

	[BZ #15467]
	* sysdeps/ieee754/dbl-64/s_sincos.c: Include <errno.h>.
	(__sincos): Set errno to EDOM for infinite argument.
	* sysdeps/ieee754/flt-32/s_sincosf.c: Include <errno.h>.
	(SINCOSF_FUNC): Set errno to EDOM for infinite argument.
	* sysdeps/ieee754/ldbl-128/s_sincosl.c: Include <errno.h>.
	(__sincosl): Set errno to EDOM for infinite argument.
	* sysdeps/ieee754/ldbl-128ibm/s_sincosl.c: Include <errno.h>.
	(__sincosl): Set errno to EDOM for infinite argument.
	* sysdeps/ieee754/ldbl-96/s_sincosl.c: Include <errno.h>.
	(__sincosl): Set errno to EDOM for infinite argument.
	* math/libm-test.inc (sincos_test_data): Test errno setting.
2015-02-11 23:17:25 +00:00
Joseph Myers
5a9e4c09a2 Fix ldbl-96 scalblnl underflowing results (bug 17803).
The ldbl-96 implementation of scalblnl (used for x86_64 and ia64) uses
a condition k <= -63 to determine when a standard underflowing result
tiny*__copysignl(tiny,x) should be returned.  However, that condition
corresponds to values with exponent -16446 or less, and in the case of
-16446, the correct result for round-to-nearest depends on whether the
value is exactly 0x1p-16446 (half the least subnormal) or more than
that.  This patch fixes the bug by changing the condition to k <= -64
and accordingly adjusting the exponent by 64 not 63 when converting to
a normal value.

Tested for x86_64.

	[BZ #17803]
	* sysdeps/ieee754/ldbl-96/s_scalblnl.c (twom63): Rename to
	twom64.  Adjust value to 0x1p-64L.
	(__scalblnl): Only return standard underflowing result for K <=
	-64 not K <= -63; adjust exponent for underflowing result by 64
	not 63.
	* math/libm-test.inc (scalbn_test_data): Add more tests.
	(scalbln_test_data): Likewise.
2015-01-12 23:02:14 +00:00
Joseph Myers
34e93d6c76 Fix ldbl-96 scalblnl for subnormal arguments (bug 17834).
The ldbl-96 implementation of scalblnl (used for x86_64 and ia64) is
incorrect for subnormal arguments (this is a separate bug from bug
17803, which is about underflowing results).  There are two problems
with the adjustments of subnormal arguments: the "two63" variable
multiplied by is actually 0x1p52L not 0x1p63L, so is insufficient to
make values normal, and then GET_LDOUBLE_EXP(es,x), used to extract
the new exponent, extracts it into a variable that isn't used, while
the value taken to by the new exponent is wrongly taken from the high
part of the mantissa before the adjustment (hx).  This patch fixes
both those problems and adds appropriate tests.

Tested for x86_64.

	[BZ #17834]
	* sysdeps/ieee754/ldbl-96/s_scalblnl.c (two63): Change value to
	0x1p63L.
	(__scalblnl): Get new exponent of adjusted subnormal value from ES
	not HX.
	* math/libm-test.inc (scalbn_test_data): Add more tests.
	(scalbln_test_data): Likewise.
2015-01-12 22:34:58 +00:00