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.
On Mon, Jan 17, 2022 at 12:11:59AM +0100, FX via Gcc-patches wrote:
> This patch is the third in my “signaling NaN” series.
> For targets with IEEE support but without the issignaling macro in libc
> (i.e., everywhere except glibc), this allows us to provide a fallback
> implementation.
This doesn't seem to handle the powerpc* IBM double double long double.
__LDBL_IS_IEC_60559__ isn't defined for this type, because it is far from
an IEEE754 type, but it has signaling NaNs - as can be seen in glibc
libc/sysdeps/ieee754/ldbl-128ibm/s_issignalingl.c
the type is a pair of doubles and whether it is a sNaN or qNaN is determined
by whether the first double is a sNaN or qNaN.
2022-01-25 Jakub Jelinek <jakub@redhat.com>
* ieee/issignaling_fallback.h (__issignalingl): Define for
IBM extended long double are returning __issignaling on the
first double.
For targets with IEEE support but without the issignaling macro in libc
(currently, everywhere except glibc), this allows us to provide a fallback
implementation. In order to keep the code in ieee_helper.c relatively
readable, I've put that new implementation in a separate file,
issignaling_fallback.h.
libgfortran/ChangeLog:
* ieee/issignaling_fallback.h: New file.
* ieee/ieee_helper.c: Include issignaling_fallback.h when target
does not define issignaling macro.
gcc/testsuite/ChangeLog:
* gfortran.dg/ieee/signaling_1.f90: Do not require issignaling.
* gfortran.dg/ieee/signaling_2.f90: Add comment.
* gfortran.dg/ieee/signaling_3.f90: New test.
These two files were introduced by mistake in
86e3b476d5
gcc/testsuite/ChangeLog:
* gfortran.dg/ieee/signaling_3.f90: Remove file.
libgfortran/ChangeLog:
* ieee/issignaling_fallback.h: Remove file.
The ABI for x87 and x86-32 is not suitable for passing around
signaling NaNs in the way IEEE expects. See for example discussion
in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57484
gcc/testsuite/ChangeLog:
* gfortran.dg/ieee/signaling_1.f90: xfail on x87.
* gfortran.dg/ieee/signaling_2.f90: xfail on x87.
I moved the library implementation of IEEE_VALUE in libgfortran from
Fortran to C code, which gives us access to GCC's built-ins for NaN generation
(both quiet and signalling). It will be perform better than the current
Fortran implementation.
libgfortran/ChangeLog:
PR fortran/82207
* mk-kinds-h.sh: Add values for TINY.
* ieee/ieee_arithmetic.F90: Call C helper functions for
IEEE_VALUE.
* ieee/ieee_helper.c: New functions ieee_value_helper_N for each
floating-point type.
gcc/testsuite/ChangeLog:
PR fortran/82207
* gfortran.dg/ieee/ieee_10.f90: Do not create signaling NaNs.
* gfortran.dg/ieee/signaling_2.f90: New test.
* gfortran.dg/ieee/signaling_2_c.c: New file.
We use the issignaling macro, present in some libc's (notably glibc),
when it is available. Compile all IEEE-related files in the library
(both C and Fortran sources) with -fsignaling-nans to ensure maximum
compatibility.
libgfortran/ChangeLog:
PR fortran/82207
* Makefile.am: Pass -fsignaling-nans for IEEE files.
* Makefile.in: Regenerate.
* ieee/ieee_helper.c: Use issignaling macro to recognized
signaling NaNs.
gcc/testsuite/ChangeLog:
PR fortran/82207
* gfortran.dg/ieee/signaling_1.f90: New test.
* gfortran.dg/ieee/signaling_1_c.c: New file.
Fortran 2018 added some synonyms to the existing values, namely
IEEE_NEGATIVE_SUBNORMAL (which is the same as IEEE_NEGATIVE_DENORMAL)
and IEEE_POSITIVE_SUBNORMAL (same as IEEE_POSITIVE_DENORMAL). When they
were added to the C side, they were not kept in sync with the Fortran
part of the library. Thew new values are not used (yet), so it is
currently harmless, but better fix it.
libgfortran/ChangeLog:
* ieee/ieee_helper.c: Fix enum values.
The FE converts the old school .eq. to ==,
and then tracks the ==. The module starts with == and so it does not
properly overload the .eq. Reversing the interfaces fixes this.
2021-02-12 Steve Kargl <sgk@troutmask.apl.washington.edu>
libgfortran/ChangeLog:
PR libfortran/95647
* ieee/ieee_arithmetic.F90: Flip interfaces of operators .eq. to
== and .ne. to /= .
gcc/testsuite/ChangeLog:
PR libfortran/95647
* gfortran.dg/ieee/ieee_12.f90: New test.
2018-12-29 Steven G. Kargl <kargl@gcc.gnu.org>
* expr.c (external_spec_function): Add ieee_support_subnormal to list
of IEEE inquiry functions.
2018-12-29 Steven G. Kargl <kargl@gcc.gnu.org>
* gfortran.map: Expose subnormal functions in dynamic library.
* ieee/ieee_arithmetic.F90: Add support for IEEE_SUBNORMAL,
IEEE_POSITIVE_SUBNORMAL, and IEEE_NEGATIVE_SUBNORMAL.
* ieee/ieee_helper.c: Ditto.
* ieee/ieee_features.F90: Add IEEE_SUBNORMAL.
2018-12-29 Steven G. Kargl <kargl@gcc.gnu.org>
* gfortran.dg/ieee/ieee_11.F90: New test.
From-SVN: r267468
2018-12-29 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/88342
* ieee/ieee_arithmetic.F90: Prevent exceptions in IEEE_VALUE if
-ffpe-trap=invalid or -ffpe-trap=overflow is used.
2018-12-29 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/88342
* gfortran.dg/ieee/ieee_10.f90: New test.
From-SVN: r267465
2018-12-21 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/69121
* ieee/ieee_arithmetic.F90: Provide missing interfaces for IEEE_SCALB.
2018-12-21 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/69121
* gfortran.dg/ieee/ieee_9.f90: New test.
From-SVN: r267343
2018-12-20 Steven G. Kargl <kargl@gcc.gnu.org>
* libgfortran/ieee/ieee_arithmetic.F90: Re-organize file to
eliminate #ifdef ... #endif. No functional change.
From-SVN: r267312
2016-09-09 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/77507
* intrinsic.c (add_functions): Use correct keyword.
2016-09-09 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/77507
* ieee/ieee_arithmetic.F90 (IEEE_VALUE_4,IEEE_VALUE_8,IEEE_VALULE_10,
IEEE_VALUE_16): Use correct keyword.
2016-09-09 Steven G. Kargl <kargl@gcc.gnu.org>
PR fortran/77507
* gfortran.dg/pr77507.f90: New test.
From-SVN: r240050
PR fortran/64022
* simplify.c (gfc_simplify_ieee_selected_real_kind): Extend IEEE
support to all real kinds.
* ieee/ieee_exceptions.F90: Support all real kinds.
* ieee/ieee_arithmetic.F90: Likewise.
* ieee/ieee_helper.c (ieee_class_helper_10,
ieee_class_helper_16): New functions
* gfortran.map (GFORTRAN_1.7): Add entries.
* gfortran.dg/ieee/ieee_7.f90: Adjust test.
* gfortran.dg/ieee/large_1.f90: New test.
From-SVN: r226548
PR fortran/29383
gcc/fortran/
* gfortran.h (gfc_simplify_ieee_selected_real_kind): New prototype.
* libgfortran.h (GFC_FPE_*): Use simple integer values, valid in
both C and Fortran.
* expr.c (gfc_check_init_expr): Simplify IEEE_SELECTED_REAL_KIND.
* simplify.c (gfc_simplify_ieee_selected_real_kind): New function.
* module.c (mio_symbol): Keep track of symbols which came from
intrinsic modules.
(gfc_use_module): Keep track of the IEEE modules.
* trans-decl.c (gfc_get_symbol_decl): Adjust code since
we have new intrinsic modules.
(gfc_build_builtin_function_decls): Build decls for
ieee_procedure_entry and ieee_procedure_exit.
(is_from_ieee_module, is_ieee_module_used, save_fp_state,
restore_fp_state): New functions.
(gfc_generate_function_code): Save and restore floating-point
state on procedure entry/exit, when IEEE modules are used.
* intrinsic.texi: Document the IEEE modules.
libgfortran/
* configure.host: Add checks for IEEE support, rework priorities.
* configure.ac: Define IEEE_SUPPORT, check for fpsetsticky and
fpresetsticky.
* configure: Regenerate.
* Makefile.am: Build new ieee files, install IEEE_* modules.
* Makefile.in: Regenerate.
* gfortran.map (GFORTRAN_1.6): Add new symbols.
* libgfortran.h (get_fpu_trap_exceptions, set_fpu_trap_exceptions,
support_fpu_trap, set_fpu_except_flags, support_fpu_flag,
support_fpu_rounding_mode, get_fpu_state, set_fpu_state): New
prototypes.
* config/fpu-*.h (get_fpu_trap_exceptions,
set_fpu_trap_exceptions, support_fpu_trap, set_fpu_except_flags,
support_fpu_flag, support_fpu_rounding_mode, get_fpu_state,
set_fpu_state): New functions.
* ieee/ieee_features.F90: New file.
* ieee/ieee_exceptions.F90: New file.
* ieee/ieee_arithmetic.F90: New file.
* ieee/ieee_helper.c: New file.
gcc/testsuite/
* lib/target-supports.exp (check_effective_target_fortran_ieee):
New function.
* gfortran.dg/ieee/ieee.exp: New file.
* gfortran.dg/ieee/ieee_1.F90: New file.
* gfortran.dg/ieee/ieee_2.f90: New file.
* gfortran.dg/ieee/ieee_3.f90: New file.
* gfortran.dg/ieee/ieee_4.f90: New file.
* gfortran.dg/ieee/ieee_5.f90: New file.
* gfortran.dg/ieee/ieee_6.f90: New file.
* gfortran.dg/ieee/ieee_7.f90: New file.
* gfortran.dg/ieee/ieee_rounding_1.f90: New file.
From-SVN: r212102
