This patch makes ldbl-96 functions use libm_alias_ldouble to define
function aliases.
Tested for x86_64, and tested with build-many-glibcs.py that installed
stripped shared libraries are unchanged by the patch.
* sysdeps/ieee754/ldbl-96/s_asinhl.c: Include
<libm-alias-ldouble.h>.
(asinhl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_cbrtl.c: Include
<libm-alias-ldouble.h>.
(cbrtl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_copysignl.c: Include
<libm-alias-ldouble.h>.
(copysignl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_cosl.c: Include
<libm-alias-ldouble.h>.
(cosl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_erfl.c: Include
<libm-alias-ldouble.h>.
(erfl): Define using libm_alias_ldouble.
(erfcl): Likewise.
* sysdeps/ieee754/ldbl-96/s_fmal.c: Include
<libm-alias-ldouble.h>.
(fmal): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_frexpl.c: Include
<libm-alias-ldouble.h>.
(frexpl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_fromfpl.c (fromfpl): Define using
libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_fromfpl_main.c: Include
<libm-alias-ldouble.h>.
* sysdeps/ieee754/ldbl-96/s_fromfpxl.c (fromfpxl): Define using
libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_getpayloadl.c: Include
<libm-alias-ldouble.h>.
(getpayloadl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_llrintl.c: Include
<libm-alias-ldouble.h>.
(llrintl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_llroundl.c: Include
<libm-alias-ldouble.h>.
(llroundl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_lrintl.c: Include
<libm-alias-ldouble.h>.
(lrintl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_lroundl.c: Include
<libm-alias-ldouble.h>.
(lroundl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_modfl.c: Include
<libm-alias-ldouble.h>.
(modfl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_nextupl.c: Include
<libm-alias-ldouble.h>.
(nextupl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_remquol.c: Include
<libm-alias-ldouble.h>.
(remquol): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_roundevenl.c: Include
<libm-alias-ldouble.h>.
(roundevenl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_roundl.c: Include
<libm-alias-ldouble.h>.
(roundl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_setpayloadl.c (setpayloadl): Define
using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_setpayloadl_main.c: Include
<libm-alias-ldouble.h>.
* sysdeps/ieee754/ldbl-96/s_setpayloadsigl.c: Include
<libm-alias-ldouble.h>.
(setpayloadsigl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_sincosl.c: Include
<libm-alias-ldouble.h>.
(sincosl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_sinl.c: Include
<libm-alias-ldouble.h>.
(sinl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_tanhl.c: Include
<libm-alias-ldouble.h>.
(tanhl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_tanl.c: Include
<libm-alias-ldouble.h>.
(tanl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_totalorderl.c: Include
<libm-alias-ldouble.h>.
(totalorderl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_totalordermagl.c: Include
<libm-alias-ldouble.h>.
(totalordermagl): Define using libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_ufromfpl.c (ufromfpl): Define using
libm_alias_ldouble.
* sysdeps/ieee754/ldbl-96/s_ufromfpxl.c (ufromfpxl): Define using
libm_alias_ldouble.
C11 defines standard <float.h> macros *_TRUE_MIN for the least
positive subnormal value of a type. Now that we build with
-std=gnu11, we can use these macros in glibc. This patch replaces
previous uses of the GCC predefines __*_DENORM_MIN__ (used in
<float.h> to define *_TRUE_MIN), as well as *_DENORM_MIN references in
comments.
Tested for x86_64 and x86 (testsuite, and that installed shared
libraries are unchanged by the patch). Also tested for powerpc that
installed stripped shared libraries are unchanged by the patch.
* math/libm-test.inc (min_subnorm_value): Use LDBL_TRUE_MIN,
DBL_TRUE_MIN and FLT_TRUE_MIN instead of __LDBL_DENORM_MIN__,
__DBL_DENORM_MIN__ and __FLT_DENORM_MIN__.
* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Refer to DBL_TRUE_MIN
instead of DBL_DENORM_MIN in comment.
* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Refer to
LDBL_TRUE_MIN instead of LDBL_DENORM_MIN in comment.
* sysdeps/ieee754/ldbl-128ibm/s_nextafterl.c: Include <float.h>.
(__nextafterl): Use LDBL_TRUE_MIN instead of __LDBL_DENORM_MIN__.
* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Refer to
LDBL_TRUE_MIN instead of LDBL_DENORM_MIN in comment.
Various fma implementations have logic that, when computing fma (x, y,
z) where z is large (so care needs taking to avoid internal overflow)
but x * y is small, scale x * y up instead of down to avoid internal
underflows resulting from scaling down. (In these cases, x * y is
small enough that only its sign actually matters rather than the exact
value.)
The threshold for scaling up instead of down was correct for "if the
unscaled values were multiplied, the low part of the multiplication
could underflow", and the scaling was sufficient to ensure that the
low part of the multiplication did not underflow (given that cases of
very small x * y - less than half the least subnormal - were
previously dealt with). However, the choice in the functions wasn't
between scaling up or no scaling, but between scaling up and scaling
down (scaling down actually being needed when x * y isn't so small
compared to z and so the exact value does matter). Thus a larger
threshold is needed to ensure that scaling down doesn't produce values
the multiplication of whose low parts underflows. This patch
increases the thresholds accordingly.
Tested for x86_64, x86 and mips64 (with the MIPS version of s_fmal.c
removed so that the ldbl-128 version gets tested instead of the
soft-fp one).
[BZ #18824]
* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Increase threshold for
scaling x * y up instead of down.
* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Likewise.
* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.
* math/auto-libm-test-in: Add more tests of fma.
* math/auto-libm-test-out: Regenerated.
