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133d0d422ebd18dbd215cfa5394aff9f938e7060
gcc/libgfortran/intrinsics/trigd.c
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Jakub Jelinek 133d0d422e fortran, libgfortran: Avoid using libquadmath for glibc 2.26+ 
As mentioned by Joseph in PR105101, glibc 2.26 or later has on x86
(both -m32/-m64), powerpc64le, ia64 and mips support for
*f128 math/complex APIs plus strtof128 and strfromf128, and these APIs allow
us to avoid libquadmath for Fortran purposes on these architectures,
replace *q math/complex APIs, strtof128 instead of strtoflt128 and,
while strfromf128 unfortunately isn't a perfect replacement to
quadmath_snprintf, it can be made to work.

The advantage of this is that when configured against such glibcs
(2.26 is now almost 5 years old), we can avoid linking against an extra shared
library and the math support in glibc is maintained better than libquadmath.

We need both a compiler change (so that for glibc 2.26+ it uses *f128 APIs
instead of *q) and library change.

The above mentioned problem with strfromf128 is that the strfrom* functions
are severely restricted versions of snprintf.  In libgfortran, we handle
!isfinite differently and just use snprintf/quadmath_snprintf for
%+-#.*{L,Q}{f,e} printing.
strfrom* doesn't allow +, -, # modifiers and it only supports .34 or
similar precision, not .* .  The L/Q etc. letters are omitted.
The + is there to force + sign at the start if it is positive.
Workaround in the patch is to add the + at the start manually for
!signbit (val).
The - (left alignment instead of right) I don't understand why we need it,
when minimum field width isn't specified (for strfrom* can't be specified),
no padding is ever added anywhere I believe.
The # is to force adding . - workaround is to search for first . or e or '\0'
character, if it is '\0', just append ., if it is e, insert . before e and
memmove the rest (which is just a few bytes, e, +/- and at most a few digits)
one byte later.
The .* case is handled by creating the format string for strfrom* by
snprintf into a temporary buffer.

As requested, this patch also switches from using __float128 type in
libgfortran to _Float128 which is equivalent on all arches that support
__float128.

The change is done in a backwards compatible change, when GCC is configured
against glibc 2.26 or newer, libgfortran.so.5 itself doesn't link against
-lquadmath nor uses any libquadmath APIs, libgfortran.a doesn't use any
libquadmath APIs either.  User programs and libraries when being linked
by gfortran driver are linked against -lgfortran and -lquadmath, but
the latter only in the --as-needed linker mode, which means it needs
to be around during linking and will be linked in if there are any
calls to math/complex functions with real(kind=16) or complex(kind=16)
in compilation units compiled by older versions of gcc, but if either
user code doesn't call those math/complex functions for the largest
supported kind, or the code is recompiled by gcc with this change in,
libquadmath won't be linked in.

2022-06-28  Jakub Jelinek  <jakub@redhat.com>

gcc/fortran/
	* gfortran.h (gfc_real_info): Add use_iec_60559 bitfield.
	* trans-types.h (gfc_real16_use_iec_60559): Declare.
	* trans-types.cc (gfc_real16_use_iec_60559): Define.
	(gfc_init_kinds): When building powerpc64le-linux libgfortran
	on glibc 2.26 to 2.31, set gfc_real16_use_iec_60559 and
	use_iec_60559.
	(gfc_build_real_type): Set gfc_real16_use_iec_60559 and use_iec_60559
	on glibc 2.26 or later.
	* trans-intrinsic.cc (gfc_build_intrinsic_lib_fndecls): Adjust
	comment.  Handle gfc_real16_use_iec_60559.
	(gfc_get_intrinsic_lib_fndecl): Handle use_iec_60559.
libgfortran/
	* configure.ac: Check for strtof128 and strfromf128.
	Check for math and complex *f128 functions.  Set
	have_iec_60559_libc_support to yes if *f128 support is around, for
	--enable-libquadmath-support default to "default" rather than yes if
	have_iec_60559_libc_support is yes.
	* acinclude.m4 (LIBGFOR_CHECK_FLOAT128): Test
	_Float128/_Complex _Float128 rather than __float128 and
	_Complex float __attribute__((mode(TC))).  If libquadmath support
	is defaulted and have_iec_60559_libc_support is yes, define and subst
	USE_IEC_60559.  Remove unused LIBGFOR_BUILD_QUAD conditional.
	* Makefile.am (kinds.h): Pass @USE_IEC_60559@ as an extra
	mk-kinds-h.sh argument.
	* mk-kinds-h.sh: Accept 4th use_iec_60559 argument.  Use
	_Float128/_Complex _Float128 types instead of __float128 and
	_Complex float __attribute__((mode(TC))), and if use_iec_60559 is yes,
	use f128 suffix instead of q and define GFC_REAL_16_USE_IEC_60559.
	* kinds-override.h: Use _Float128/_Complex _Float128 types instead of
	__float128 and _Complex float __attribute__((mode(TC))), if
	USE_IEC_60559 is defined, use f128 suffixes instead of q and
	define GFC_REAL_17_USE_IEC_60559.
	* libgfortran.h: Don't include quadmath_weak.h if USE_IEC_60559 is
	defined.
	(GFC_REAL_16_INFINITY, GFC_REAL_16_QUIET_NAN): Define
	for GFC_REAL_16_USE_IEC_60559 differently.
	* caf/single.c (convert_type): Use _Float128/_Complex _Float128
	instead of __float128 and _Complex float __attribute__((mode(TC))).
	For HAVE_GFC_REAL_10 when HAVE_GFC_REAL_16 isn't defined use
	_Complex long double instead of long double.
	* ieee/issignaling_fallback.h (ieee854_float128_shape_type): Use
	_Float128 instead of __float128.
	(__issignalingf128): Change argument type to _Float128.
	(issignaling): Use _Float128 instead of __float128 in _Generic.
	* intrinsics/cshift0.c (cshift0): Use _Float128 instead of __float128
	in a comment.  Fix a comment typo, logn double -> long double.
	* intrinsics/erfc_scaled.c (_THRESH, _M_2_SQRTPI, _INF, _ERFC, _EXP):
	Use different definitions if GFC_REAL_16_USE_IEC_60559.
	(_THRESH, _M_2_SQRTPI): Use GFC_REAL_17_LITERAL macro.
	(_ERFC, _EXP): Use different definitions if GFC_REAL_17_USE_IEC_60559.
	* intrinsics/spread_generic.c (spread, spread_scalar): Use _Float128
	instead of __float128 in a comment.  Fix a comment typo,
	logn double -> long double.
	* intrinsics/trigd.c (ENABLE_SIND, ENABLE_COSD, ENABLE_TAND): Handle
	GFC_REAL_16_USE_IEC_60559.
	* intrinsics/pack_generic.c (pack): Use _Float128 instead of
	__float128 in a comment.  Fix a comment typo, logn double ->
	long double.
	* intrinsics/unpack_generic.c (unpack1, unpack0): Likewise.
	* runtime/in_pack_generic.c (internal_pack): Likewise.
	* runtime/in_unpack_generic.c (internal_unpack): Likewise.
	* io/read.c (convert_real, convert_infnan): Handle
	GFC_REAL_16_USE_IEC_60559 and GFC_REAL_17_USE_IEC_60559.
	* io/transfer128.c (tmp1, tmp2): Don't define if libquadmath
	isn't needed.
	* io/write_float.def (gfor_strfromf128): New function.
	(DTOA2Q, FDTOA2Q): Define differently if
	GFC_REAL_16_USE_IEC_60559 or GFC_REAL_17_USE_IEC_60559.
	* m4/mtype.m4: Use different suffix if GFC_REAL_16_USE_IEC_60559
	or GFC_REAL_17_USE_IEC_60559.
	* config.h.in: Regenerated.
	* configure: Regenerated.
	* Makefile.in: Regenerated.
	* generated/bessel_r16.c: Regenerated.
	* generated/bessel_r17.c: Regenerated.
	* generated/norm2_r16.c: Regenerated.
	* generated/norm2_r17.c: Regenerated.
2022-06-28 13:14:45 +02:00

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/* Implementation of the degree trignometric functions COSD, SIND, TAND.
Copyright (C) 2020-2022 Free Software Foundation, Inc.
Contributed by Steven G. Kargl <kargl@gcc.gnu.org>
This file is part of the GNU Fortran runtime library (libgfortran).
Libgfortran is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
Libgfortran is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "libgfortran.h"
#include <math.h>
/* Body of library functions which are cannot be implemented on the current
* platform because it lacks a capability, such as an underlying trigonometric
* function (sin, cos, tan) or C99 floating-point function (fabs, fmod). */
#define STRINGIFY_EXPAND(x) #x
#define ERROR_RETURN(f, k, x) runtime_error (#f " is unavailable for" \
" REAL(KIND=" STRINGIFY_EXPAND(k) ") because the system math library" \
" lacks support for it"); \
RETURN(x)
/*
For real x, let {x}_P or x_P be the closest representible number in the
floating point representation which uses P binary bits of fractional
precision (with IEEE rounding semantics).
Similarly, let f_P(x) be shorthand for {f(x)}_P.
Let ulp_P(x) be the unit of least precision for x: in other words the
maximal value of |a_P - b_P| where a_P <= x <= b_P and a_P != b_P.
Let x ~= y <-> | x - y | < ulp_P(x - y).
Let deg(x) be the value of x radians in degrees.
Values for each precision P were selected as follows.
COSD_SMALL = 2**{-N} such that for all x <= COSD_SMALL:
* cos(deg(x)) ~= 1, or equivalently:
| 1 - cos(deg(x)) | < ulp_P(1).
Unfortunately for SIND (and therefore TAND) a similar relation is only
possible for REAL(4) and REAL(8). With REAL(10) and REAL(16), enough
precision is available such that sin_P(x) != x_P for some x less than any
value. (There are values where this equality holds, but the distance has
inflection points.)
For REAL(4) and REAL(8), we can select SIND_SMALL such that:
* sin(deg(x)) ~= deg(x), or equivalently:
| deg(x) - sin(deg(x)) | < ulp_P(deg(x)).
*/
#ifdef HAVE_GFC_REAL_4
/* Build _gfortran_sind_r4, _gfortran_cosd_r4, and _gfortran_tand_r4 */
#define KIND 4
#define TINY 0x1.p-100 /* ~= 7.889e-31 */
#define COSD_SMALL 0x1.p-7 /* = 7.8125e-3 */
#define SIND_SMALL 0x1.p-5 /* = 3.125e-2 */
#define COSD30 8.66025388e-01
#define PIO180H 1.74560547e-02 /* high 12 bits. */
#define PIO180L -2.76216747e-06 /* Next 24 bits. */
#if defined(HAVE_FABSF) && defined(HAVE_FMODF) && defined(HAVE_COPYSIGNF)
#ifdef HAVE_SINF
#define ENABLE_SIND
#endif
#ifdef HAVE_COSF
#define ENABLE_COSD
#endif
#ifdef HAVE_TANF
#define ENABLE_TAND
#endif
#endif /* HAVE_FABSF && HAVE_FMODF && HAVE_COPYSIGNF */
#ifdef GFC_REAL_4_INFINITY
#define HAVE_INFINITY_KIND
#endif
#include "trigd_lib.inc"
#undef KIND
#undef TINY
#undef COSD_SMALL
#undef SIND_SMALL
#undef COSD30
#undef PIO180H
#undef PIO180L
#undef ENABLE_SIND
#undef ENABLE_COSD
#undef ENABLE_TAND
#undef HAVE_INFINITY_KIND
#endif /* HAVE_GFC_REAL_4... */
#ifdef HAVE_GFC_REAL_8
/* Build _gfortran_sind_r8, _gfortran_cosd_r8, and _gfortran_tand_r8 */
#define KIND 8
#define TINY 0x1.p-1000 /* ~= 9.33e-302 (min exp -1074) */
#define COSD_SMALL 0x1.p-21 /* ~= 4.768e-7 */
#define SIND_SMALL 0x1.p-19 /* ~= 9.537e-7 */
#define COSD30 8.6602540378443860e-01
#define PIO180H 1.7453283071517944e-02 /* high 21 bits. */
#define PIO180L 9.4484253514332993e-09 /* Next 53 bits. */
#if defined(HAVE_FABS) && defined(HAVE_FMOD) && defined(HAVE_COPYSIGN)
#ifdef HAVE_SIN
#define ENABLE_SIND
#endif
#ifdef HAVE_COS
#define ENABLE_COSD
#endif
#ifdef HAVE_TAN
#define ENABLE_TAND
#endif
#endif /* HAVE_FABS && HAVE_FMOD && HAVE_COPYSIGN */
#ifdef GFC_REAL_8_INFINITY
#define HAVE_INFINITY_KIND
#endif
#include "trigd_lib.inc"
#undef KIND
#undef TINY
#undef COSD_SMALL
#undef SIND_SMALL
#undef COSD30
#undef PIO180H
#undef PIO180L
#undef ENABLE_SIND
#undef ENABLE_COSD
#undef ENABLE_TAND
#undef HAVE_INFINITY_KIND
#endif /* HAVE_GFC_REAL_8... */
#ifdef HAVE_GFC_REAL_10
/* Build _gfortran_sind_r10, _gfortran_cosd_r10, and _gfortran_tand_r10 */
#define KIND 10
#define TINY 0x1.p-16400 /* ~= 1.28e-4937 (min exp -16494) */
#define COSD_SMALL 0x1.p-26 /* ~= 1.490e-8 */
#undef SIND_SMALL /* not precise */
#define COSD30 8.66025403784438646787e-01
#define PIO180H 1.74532925229868851602e-02 /* high 32 bits */
#define PIO180L -3.04358939097084072823e-12 /* Next 64 bits */
#if defined(HAVE_FABSL) && defined(HAVE_FMODL) && defined(HAVE_COPYSIGNL)
#ifdef HAVE_SINL
#define ENABLE_SIND
#endif
#ifdef HAVE_COSL
#define ENABLE_COSD
#endif
#ifdef HAVE_TANL
#define ENABLE_TAND
#endif
#endif /* HAVE_FABSL && HAVE_FMODL && HAVE_COPYSIGNL */
#ifdef GFC_REAL_10_INFINITY
#define HAVE_INFINITY_KIND
#endif
#include "trigd_lib.inc"
#undef KIND
#undef TINY
#undef COSD_SMALL
#undef SIND_SMALL
#undef COSD30
#undef PIO180H
#undef PIO180L
#undef ENABLE_SIND
#undef ENABLE_COSD
#undef ENABLE_TAND
#undef HAVE_INFINITY_KIND
#endif /* HAVE_GFC_REAL_10 */
#ifdef HAVE_GFC_REAL_16
/* Build _gfortran_sind_r16, _gfortran_cosd_r16, and _gfortran_tand_r16 */
#define KIND 16
#define TINY 0x1.p-16400 /* ~= 1.28e-4937 */
#undef SIND_SMALL /* not precise */
#if GFC_REAL_16_DIGITS == 64
/* 80 bit precision, use constants from REAL(10). */
#define COSD_SMALL 0x1.p-26 /* ~= 1.490e-8 */
#define COSD30 8.66025403784438646787e-01
#define PIO180H 1.74532925229868851602e-02 /* high 32 bits */
#define PIO180L -3.04358939097084072823e-12 /* Next 64 bits */
#else
/* Proper float128 precision. */
#define COSD_SMALL 0x1.p-51 /* ~= 4.441e-16 */
#define COSD30 8.66025403784438646763723170752936183e-01
#define PIO180H 1.74532925199433197605003442731685936e-02
#define PIO180L -2.39912634365882824665106671063098954e-17
#endif
#ifdef GFC_REAL_16_IS_LONG_DOUBLE
#if defined(HAVE_FABSL) && defined(HAVE_FMODL) && defined(HAVE_COPYSIGNL)
#ifdef HAVE_SINL
#define ENABLE_SIND
#endif
#ifdef HAVE_COSL
#define ENABLE_COSD
#endif
#ifdef HAVE_TANL
#define ENABLE_TAND
#endif
#endif /* HAVE_FABSL && HAVE_FMODL && HAVE_COPYSIGNL */
#elif defined(GFC_REAL_16_USE_IEC_60559)
#if defined(HAVE_FABSF128) && defined(HAVE_FMODF128) && defined(HAVE_COPYSIGNF128)
#ifdef HAVE_SINF128
#define ENABLE_SIND
#endif
#ifdef HAVE_COSF128
#define ENABLE_COSD
#endif
#ifdef HAVE_TANF128
#define ENABLE_TAND
#endif
#endif /* HAVE_FABSF128 && HAVE_FMODF128 && HAVE_COPYSIGNF128 */
#else
/* libquadmath: HAVE_*Q are never defined. They must be available. */
#define ENABLE_SIND
#define ENABLE_COSD
#define ENABLE_TAND
#endif /* GFC_REAL_16_IS_LONG_DOUBLE */
#ifdef GFC_REAL_16_INFINITY
#define HAVE_INFINITY_KIND
#endif
#include "trigd_lib.inc"
#undef KIND
#undef TINY
#undef COSD_SMALL
#undef SIND_SMALL
#undef COSD30
#undef PIO180H
#undef PIO180L
#undef ENABLE_SIND
#undef ENABLE_COSD
#undef ENABLE_TAND
#undef HAVE_INFINITY_KIND
#endif /* HAVE_GFC_REAL_16 */
#ifdef HAVE_GFC_REAL_17
/* Build _gfortran_sind_r17, _gfortran_cosd_r17, and _gfortran_tand_r17 */
#define KIND 17
#define TINY 0x1.p-16400 /* ~= 1.28e-4937 */
#undef SIND_SMALL /* not precise */
/* Proper float128 precision. */
#define COSD_SMALL 0x1.p-51 /* ~= 4.441e-16 */
#define COSD30 8.66025403784438646763723170752936183e-01
#define PIO180H 1.74532925199433197605003442731685936e-02
#define PIO180L -2.39912634365882824665106671063098954e-17
/* libquadmath or glibc 2.32+: HAVE_*Q are never defined. They must be available. */
#define ENABLE_SIND
#define ENABLE_COSD
#define ENABLE_TAND
#ifdef GFC_REAL_17_INFINITY
#define HAVE_INFINITY_KIND
#endif
#ifdef POWER_IEEE128
#define COPYSIGN __copysignieee128
#define FMOD __fmodieee128
#define FABS __fabsieee128
#define FMA __fmaieee128
#define SIN __sinieee128
#define COS __cosieee128
#define TAN __tanieee128
#endif
#include "trigd_lib.inc"
#undef KIND
#undef TINY
#undef COSD_SMALL
#undef SIND_SMALL
#undef COSD30
#undef PIO180H
#undef PIO180L
#undef ENABLE_SIND
#undef ENABLE_COSD
#undef ENABLE_TAND
#undef HAVE_INFINITY_KIND
#endif /* HAVE_GFC_REAL_17 */
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