glibc/sysdeps/i386/fpu
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 ]
	* 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
..
doasin.c Update. 2001-03-12 00:04:52 +00:00
e_acos.S Fix x86 acos near 1 (bug 13942). 2012-04-30 18:56:39 +00:00
e_acosf.S Fix acos (-1) in round-downwards mode on x86 (bug 14034). 2012-04-30 09:38:06 +00:00
e_acosh.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_acoshf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_acoshl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_acosl.c Fix x86 acos near 1 (bug 13942). 2012-04-30 18:56:39 +00:00
e_asin.S Fix x86 acos near 1 (bug 13942). 2012-04-30 18:56:39 +00:00
e_asinf.S Optimize libm 2011-10-12 11:27:51 -04:00
e_atan2.S Fix atan / atan2 missing underflows (bug 15319). 2015-02-18 21:10:49 +00:00
e_atan2f.S Fix atan / atan2 missing underflows (bug 15319). 2015-02-18 21:10:49 +00:00
e_atan2l.c Optimize libm 2011-10-12 11:27:51 -04:00
e_atanh.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_atanhf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_atanhl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_exp2.S Optimize libm 2011-10-12 11:27:51 -04:00
e_exp2f.S Optimize libm 2011-10-12 11:27:51 -04:00
e_exp2l.S Fix exp2 spurious underflows (bug 16560). 2015-02-12 19:02:45 +00:00
e_exp10.S Optimize libm 2011-10-12 11:27:51 -04:00
e_exp10f.S Optimize libm 2011-10-12 11:27:51 -04:00
e_exp10l.S Fix exp10 inaccuracy and exceptions (bugs 13884, 13914). 2012-05-06 18:23:44 +00:00
e_exp.S Optimize exp 2011-10-15 20:22:59 -04:00
e_expf.S Optimize exp 2011-10-15 20:22:59 -04:00
e_expl.S Fix x86/x86_64 expm1l spurious underflow exceptions (bug 16539). 2014-06-24 21:00:08 +00:00
e_fmod.S Optimize libm 2011-10-12 11:27:51 -04:00
e_fmodf.S Optimize libm 2011-10-12 11:27:51 -04:00
e_fmodl.c Optimize libm 2011-10-12 11:27:51 -04:00
e_hypot.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_hypotf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_ilogb.S Remove useless __ilogb*_finite aliases 2012-04-18 00:40:13 +02:00
e_ilogbf.S Remove useless __ilogb*_finite aliases 2012-04-18 00:40:13 +02:00
e_ilogbl.S Remove useless __ilogb*_finite aliases 2012-04-18 00:40:13 +02:00
e_log2.S Fix log2 (1) in round-downward mode (bug 17042). 2014-06-10 12:07:15 +00:00
e_log2f.S Fix log2 (1) in round-downward mode (bug 17042). 2014-06-10 12:07:15 +00:00
e_log2l.S Fix log2 (1) in round-downward mode (bug 17042). 2014-06-10 12:07:15 +00:00
e_log10.S Fix log10 (1) in round-downward mode (bug 16977). 2014-05-23 12:07:50 +00:00
e_log10f.S Fix log10 (1) in round-downward mode (bug 16977). 2014-05-23 12:07:50 +00:00
e_log10l.S Fix log10 (1) in round-downward mode (bug 16977). 2014-05-23 12:07:50 +00:00
e_log.S Fix log (1) in round-downward mode (bug 16731). 2014-03-21 18:13:58 +00:00
e_logf.S Fix log (1) in round-downward mode (bug 16731). 2014-03-21 18:13:58 +00:00
e_logl.S Fix __ieee754_logl (-LDBL_MAX) in FE_DOWNWARD mode (bug 17022). 2014-06-18 12:32:01 +00:00
e_pow.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_powf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_powl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
e_rem_pio2.c Update. 1999-07-14 00:54:57 +00:00
e_remainder.S Optimize libm 2011-10-12 11:27:51 -04:00
e_remainderf.S Optimize libm 2011-10-12 11:27:51 -04:00
e_remainderl.S Optimize libm 2011-10-12 11:27:51 -04:00
e_scalb.S Get rid of ASM_TYPE_DIRECTIVE{,_PREFIX}. 2012-08-02 21:04:29 +02:00
e_scalbf.S Get rid of ASM_TYPE_DIRECTIVE{,_PREFIX}. 2012-08-02 21:04:29 +02:00
e_scalbl.S Get rid of ASM_TYPE_DIRECTIVE{,_PREFIX}. 2012-08-02 21:04:29 +02:00
e_sqrt.S Fix x86 sqrt rounding (bug 14032). 2013-11-29 16:31:16 +00:00
e_sqrtf.S Optimize libm 2011-10-12 11:27:51 -04:00
e_sqrtl.c Optimize libm 2011-10-12 11:27:51 -04:00
fclrexcpt.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fedisblxcpt.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
feenablxcpt.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fegetenv.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fegetexcept.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fegetround.c Fix libm fegetround namespace (bug 17748). 2015-01-02 20:44:42 +00:00
feholdexcpt.c Fix libm feholdexcept namespace (bug 17748). 2015-01-05 23:06:14 +00:00
fenv_private.h Fix yn overflow handling in non-default rounding modes (bug 16561, bug 16562). 2014-06-27 14:52:13 +00:00
fesetenv.c Fix libm fesetenv namespace (bug 17748). 2015-01-06 23:36:20 +00:00
fesetround.c Fix libm fesetround namespace (bug 17748). 2015-01-07 00:41:23 +00:00
feupdateenv.c Fix libm feupdateenv namespace (bug 17748). 2015-01-07 19:01:20 +00:00
fgetexcptflg.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fraiseexcpt.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
fsetexcptflg.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
ftestexcept.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
halfulp.c Update. 2001-03-12 00:04:52 +00:00
Implies Use x86_64 fpu/bits/fenv.h for i386 and x86_64 2012-06-06 10:13:19 -07:00
k_rem_pio2l.c Update. 1999-07-14 00:54:57 +00:00
libm-test-ulps Fix atan / atan2 missing underflows (bug 15319). 2015-02-18 21:10:49 +00:00
math_private.h Optimize private 387 fenv access; share code between i386 and x86_64. 2012-03-19 06:51:39 -07:00
math-tests.h Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
mpatan2.c Update. 2001-03-12 00:04:52 +00:00
mpatan.c Update. 2001-03-12 00:04:52 +00:00
mpexp.c Update. 2001-03-12 00:04:52 +00:00
mplog.c Update. 2001-03-12 00:04:52 +00:00
mpsqrt.c Update. 2001-03-12 00:04:52 +00:00
s_asinh.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_asinhf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_asinhl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_atan.S Fix atan / atan2 missing underflows (bug 15319). 2015-02-18 21:10:49 +00:00
s_atanf.S Fix atan / atan2 missing underflows (bug 15319). 2015-02-18 21:10:49 +00:00
s_atanl.c Update. 2001-05-06 17:03:45 +00:00
s_cbrt.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_cbrtf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_cbrtl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_ceil.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_ceilf.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_ceill.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_copysign.S Update. 1999-07-14 00:54:57 +00:00
s_copysignf.S Update. 1999-07-14 00:54:57 +00:00
s_copysignl.S Update. 1999-07-14 00:54:57 +00:00
s_expm1.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_expm1f.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_expm1l.S Fix x86/x86_64 expm1l inaccuracy and exceptions (bugs 13885, 13923). 2012-05-07 19:13:08 +00:00
s_fabs.S Update. 2002-04-03 00:36:12 +00:00
s_fabsf.S Update. 2002-04-03 00:36:12 +00:00
s_fabsl.S Update. 2002-04-03 00:36:12 +00:00
s_fdim.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fdimf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fdiml.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_finite.S Update. 2002-09-10 01:40:26 +00:00
s_finitef.S Update. 2002-09-10 01:40:26 +00:00
s_finitel.S Update. 2002-09-10 01:40:26 +00:00
s_floor.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_floorf.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_floorl.S Add CFI to x86 ceil / floor / trunc (bug 16681). 2014-06-16 22:54:46 +00:00
s_fmax.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fmaxf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fmaxl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fmin.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fminf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fminl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_fpclassifyl.c Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_frexp.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_frexpf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_frexpl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_isinfl.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
s_isnanl.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
s_llrint.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_llrintf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_llrintl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_log1p.S Remove __ELF__ conditionals 2012-02-07 00:41:11 +01:00
s_log1pf.S Remove __ELF__ conditionals 2012-02-07 00:41:11 +01:00
s_log1pl.S Fix log1pl (LDBL_MAX) in FE_UPWARD mode (bug 16564). 2014-05-14 12:38:56 +00:00
s_logb.S Update. 1999-07-14 00:54:57 +00:00
s_logbf.S Update. 1999-07-14 00:54:57 +00:00
s_logbl.c Update. 2001-09-18 14:13:20 +00:00
s_lrint.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_lrintf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_lrintl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_nearbyint.S * intl/Makefile (tst-gettext[45].out): Pass also $(run-program-prefix) 2005-05-04 17:58:13 +00:00
s_nearbyintf.S * intl/Makefile (tst-gettext[45].out): Pass also $(run-program-prefix) 2005-05-04 17:58:13 +00:00
s_nearbyintl.S * intl/Makefile (tst-gettext[45].out): Pass also $(run-program-prefix) 2005-05-04 17:58:13 +00:00
s_nextafterl.c Fix nextafter overflow in non-default rounding modes (bug 16677). 2014-03-11 22:24:00 +00:00
s_nexttoward.c Fix nexttoward bugs (bugs 2550, 2570). 2012-05-01 15:37:43 +00:00
s_nexttowardf.c Fix nexttoward bugs (bugs 2550, 2570). 2012-05-01 15:37:43 +00:00
s_remquo.S Remove remaining bounded-pointers support from i386 .S files. 2013-02-21 22:21:52 +00:00
s_remquof.S Remove remaining bounded-pointers support from i386 .S files. 2013-02-21 22:21:52 +00:00
s_remquol.S Remove remaining bounded-pointers support from i386 .S files. 2013-02-21 22:21:52 +00:00
s_rint.S Update. 1999-07-14 00:54:57 +00:00
s_rintf.S Update. 1999-07-14 00:54:57 +00:00
s_rintl.c Update. 2001-09-18 14:13:20 +00:00
s_scalbln.c Update. 1999-07-14 00:54:57 +00:00
s_scalblnf.c Update. 1999-07-14 00:54:57 +00:00
s_scalblnl.c Update. 1999-07-14 00:54:57 +00:00
s_scalbn.S Add compat symbols for scalb* in i386 2014-06-25 08:47:13 +05:30
s_scalbnf.S Add compat symbols for scalb* in i386 2014-06-25 08:47:13 +05:30
s_scalbnl.S Add compat symbols for scalb* in i386 2014-06-25 08:47:13 +05:30
s_significand.S Update. 1999-07-14 00:54:57 +00:00
s_significandf.S Update. 1999-07-14 00:54:57 +00:00
s_significandl.c (__significandl): Really return significand and not the exponent. 2003-01-07 07:42:11 +00:00
s_trunc.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_truncf.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
s_truncl.S Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
slowexp.c Update. 2001-03-12 00:04:52 +00:00
slowpow.c Update. 2001-03-12 00:04:52 +00:00
t_exp.c Update. 1999-07-14 00:54:57 +00:00
Versions Update. 2000-06-14 00:55:24 +00:00
w_sqrt.c Fix x86 sqrt rounding (bug 14032). 2013-11-29 16:31:16 +00:00