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Clean up Fortran __float128 configure-time checks (HDFGroup#4649)
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* Always use DECIMAL_DIG instead of LDBL_DIG. This was controlled by
  an ifdef that is always true in C99 or greater

It's confusing to use float.h C constants as variable names in
configure.ac and the PAC_FC_LDBL_DIG macro.

* Directly compare MY_FLT128_DIG and MY_LDBL_DIG

* Make uniform across CMake and Autotools
* Don't export quadmath.h variables to H5pubconf.h
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@derobins @qkoziol
derobins authored and qkoziol committed Jul 16, 2024
1 parent 4fbb888 commit 4f26344
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Showing 7 changed files with 170 additions and 106 deletions.
102 changes: 60 additions & 42 deletions config/cmake/ConfigureChecks.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -133,11 +133,15 @@ endif ()

## Check for non-standard extension quadmath.h

CHECK_INCLUDE_FILES(quadmath.h C_HAVE_QUADMATH)
if (C_HAVE_QUADMATH)
set(${HDF_PREFIX}_HAVE_QUADMATH_H 1)
# gcc puts symbols like FLT128_DIG in quadmath.h instead of float.h, so
# check for that. This is only used by the build system and doesn't need
# to be exported to H5pubconf.h.
CHECK_INCLUDE_FILES("quadmath.h" INCLUDE_QUADMATH_H)
# Convert TRUE/FALSE to 0/1 for preprocessor values in test code, below
if (${INCLUDE_QUADMATH_H})
set(C_INCLUDE_QUADMATH_H 1)
else ()
set(${HDF_PREFIX}_HAVE_QUADMATH_H 0)
set(C_INCLUDE_QUADMATH_H 0)
endif ()

if (CYGWIN)
Expand Down Expand Up @@ -641,22 +645,38 @@ endif()
#-----------------------------------------------------------------------------

if (HDF5_BUILD_FORTRAN)
HDF_CHECK_TYPE_SIZE(__float128 _SIZEOF___FLOAT128)
if (_SIZEOF___FLOAT128)
set (${HDF_PREFIX}_HAVE_FLOAT128 1)
set (${HDF_PREFIX}_SIZEOF___FLOAT128 ${_SIZEOF___FLOAT128})
else ()
set (${HDF_PREFIX}_HAVE_FLOAT128 0)
set (${HDF_PREFIX}_SIZEOF___FLOAT128 0)
endif ()
# ----------------------------------------------------------------------
# __float128 checks
#
# If __float128 exists and we can determine its precision, we will use
# it in the Fortran interface. The checks for this require that the
# precision be specified via a symbol named FLT128_DIG, which might be
# found in quadmath.h.
#
# The checks here are based on the GNU __float128 extension type from
# libquadmath, which is now part of gcc. Other compilers (clang, Intel)
# also expose __float128 and/or __float128 may be an alias for some
# other 128-bit floating point type.
#
# 128-bit floating-point math is usually handled in software and is thus
# orders of magnitude slower than hardware-supported floating-point math.
#

HDF_CHECK_TYPE_SIZE(_Quad _SIZEOF__QUAD)
if (NOT _SIZEOF__QUAD)
set (${HDF_PREFIX}_SIZEOF__QUAD 0)
#-----------------------------------------------------------------------------
# Is the __float128 type available?
#-----------------------------------------------------------------------------
HDF_FUNCTION_TEST (HAVE___FLOAT128)
# Convert TRUE/FALSE to 0/1 for preprocessor values in test code, below
if (${HAVE___FLOAT128})
set(C_HAVE_FLOAT128 1)
else ()
set (${HDF_PREFIX}_SIZEOF__QUAD ${_SIZEOF__QUAD})
set(C_HAVE_FLOAT128 0)
endif ()

#-----------------------------------------------------------------------------
# Get the max decimal precision in C, checking both long double and
# __float128 (if available)
#-----------------------------------------------------------------------------
if (NOT CMAKE_CROSSCOMPILING)
#-----------------------------------------------------------------------------
# The provided CMake C macros don't provide a general compile/run function
Expand All @@ -677,7 +697,6 @@ if (HDF5_BUILD_FORTRAN)
TRY_RUN (RUN_RESULT_VAR COMPILE_RESULT_VAR
${CMAKE_BINARY_DIR}
${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/testCCompiler1.c
COMPILE_DEFINITIONS "-D_SIZEOF___FLOAT128=${H5_SIZEOF___FLOAT128};-D_HAVE_QUADMATH_H=${H5_HAVE_QUADMATH_H}"
COMPILE_OUTPUT_VARIABLE COMPILEOUT
${_RUN_OUTPUT_VARIABLE} OUTPUT_VAR
)
Expand Down Expand Up @@ -714,43 +733,42 @@ if (HDF5_BUILD_FORTRAN)
"
#include <float.h>\n\
#include <stdio.h>\n\
#define CHECK_FLOAT128 _SIZEOF___FLOAT128\n\
#if CHECK_FLOAT128!=0\n\
#if _HAVE_QUADMATH_H!=0\n\
#include <quadmath.h>\n\
#endif\n\
#ifdef FLT128_DIG\n\
#define C_FLT128_DIG FLT128_DIG\n\
#else\n\
#define C_FLT128_DIG 0\n\
#endif\n\
#if ${C_HAVE_FLOAT128}\n\
# if ${C_INCLUDE_QUADMATH_H}\n\
# include <quadmath.h>\n\
# endif\n\
# ifdef FLT128_DIG\n\
# define C_FLT128_DIG FLT128_DIG\n\
# else\n\
# define C_FLT128_DIG 0\n\
# endif\n\
#else\n\
#define C_FLT128_DIG 0\n\
# define C_FLT128_DIG 0\n\
#endif\n\
#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L\n\
#define C_LDBL_DIG DECIMAL_DIG\n\
#else\n\
#define C_LDBL_DIG LDBL_DIG\n\
#endif\n\nint main(void) {\nprintf(\"\\%d\\\;\\%d\\\;\", C_LDBL_DIG, C_FLT128_DIG)\\\;\n\nreturn 0\\\;\n}\n
"
\n\
int main(void) {\nprintf(\"\\%d\\\;\\%d\\\;\", C_LDBL_DIG, C_FLT128_DIG)\\\;\n\nreturn 0\\\;\n}\n
"
)

C_RUN ("maximum decimal precision for C" ${PROG_SRC} PROG_RES PROG_OUTPUT4)
message (STATUS "Testing maximum decimal precision for C - ${PROG_OUTPUT4}")

# dnl The output from the above program will be:
# dnl -- long double decimal precision -- __float128 decimal precision
# The output from the above program will be:
# -- long double decimal precision -- __float128 decimal precision

list (GET PROG_OUTPUT4 0 H5_LDBL_DIG)
list (GET PROG_OUTPUT4 1 H5_FLT128_DIG)
list (GET PROG_OUTPUT4 0 MY_LDBL_DIG)
list (GET PROG_OUTPUT4 1 MY_FLT128_DIG)

if (${HDF_PREFIX}_SIZEOF___FLOAT128 EQUAL "0" OR FLT128_DIG EQUAL "0")
set (${HDF_PREFIX}_HAVE_FLOAT128 0)
set (${HDF_PREFIX}_SIZEOF___FLOAT128 0)
set (_PAC_C_MAX_REAL_PRECISION ${H5_LDBL_DIG})
# Set configure output and behavior
if (${HAVE___FLOAT128} AND (${MY_FLT128_DIG} GREATER ${MY_LDBL_DIG}))
set (${HDF_PREFIX}_HAVE_FLOAT128 1)
set (_PAC_C_MAX_REAL_PRECISION ${MY_FLT128_DIG})
else ()
set (_PAC_C_MAX_REAL_PRECISION ${H5_FLT128_DIG})
# No __float128 or the precision of __float128 <= that of long double
set (_PAC_C_MAX_REAL_PRECISION ${MY_LDBL_DIG})
endif ()

if (NOT ${_PAC_C_MAX_REAL_PRECISION})
set (${HDF_PREFIX}_PAC_C_MAX_REAL_PRECISION 0)
else ()
Expand Down
11 changes: 1 addition & 10 deletions config/cmake/H5pubconf.h.in
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Original file line number Diff line number Diff line change
Expand Up @@ -144,7 +144,7 @@
/* Determine if _Float16 is available */
#cmakedefine H5_HAVE__FLOAT16 @H5_HAVE__FLOAT16@

/* Determine if __float128 is available */
/* Determine if __float128 will be used in the Fortran wrappers */
#cmakedefine H5_HAVE_FLOAT128 @H5_HAVE_FLOAT128@

/* Define to 1 if you have the `flock' function. */
Expand Down Expand Up @@ -265,9 +265,6 @@
/* Define to 1 if you have the <pwd.h> header file. */
#cmakedefine H5_HAVE_PWD_H @H5_HAVE_PWD_H@

/* Define to 1 if you have the <quadmath.h> header file. */
#cmakedefine H5_HAVE_QUADMATH_H @H5_HAVE_QUADMATH_H@

/* Define whether the Read-Only S3 virtual file driver (VFD) should be
compiled */
#cmakedefine H5_HAVE_ROS3_VFD @H5_HAVE_ROS3_VFD@
Expand Down Expand Up @@ -595,15 +592,9 @@
/* The size of `unsigned', as computed by sizeof. */
#cmakedefine H5_SIZEOF_UNSIGNED @H5_SIZEOF_UNSIGNED@

/* The size of `_Quad', as computed by sizeof. */
#define H5_SIZEOF__QUAD @H5_SIZEOF__QUAD@

/* The size of `_Float16', as computed by sizeof. */
#define H5_SIZEOF__FLOAT16 @H5_SIZEOF__FLOAT16@

/* The size of `__float128', as computed by sizeof. */
#define H5_SIZEOF___FLOAT128 @H5_SIZEOF___FLOAT128@

/* Define if strict file format checks are enabled */
#cmakedefine H5_STRICT_FORMAT_CHECKS @H5_STRICT_FORMAT_CHECKS@

Expand Down
23 changes: 11 additions & 12 deletions config/cmake/HDF5UseFortran.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -363,13 +363,13 @@ set (PROG_SRC3
"
)
FORTRAN_RUN ("SIZEOF NATIVE KINDs" ${PROG_SRC3} XX YY PAC_SIZEOF_NATIVE_KINDS_RESULT PROG_OUTPUT3)
# dnl The output from the above program will be:
# dnl -- LINE 1 -- sizeof INTEGER
# dnl -- LINE 2 -- kind of INTEGER
# dnl -- LINE 3 -- sizeof REAL
# dnl -- LINE 4 -- kind of REAL
# dnl -- LINE 5 -- sizeof DOUBLE PRECISION
# dnl -- LINE 6 -- kind of DOUBLE PRECISION
# The output from the above program will be:
# -- LINE 1 -- sizeof INTEGER
# -- LINE 2 -- kind of INTEGER
# -- LINE 3 -- sizeof REAL
# -- LINE 4 -- kind of REAL
# -- LINE 5 -- sizeof DOUBLE PRECISION
# -- LINE 6 -- kind of DOUBLE PRECISION
#
# Convert the string to a list of strings by replacing the carriage return with a semicolon
string (REGEX REPLACE "[\r\n]+" ";" PROG_OUTPUT3 "${PROG_OUTPUT3}")
Expand Down Expand Up @@ -402,11 +402,10 @@ endif ()

set (${HDF_PREFIX}_FORTRAN_SIZEOF_LONG_DOUBLE ${${HDF_PREFIX}_SIZEOF_LONG_DOUBLE})

# remove the invalid kind from the list
if (NOT(${${HDF_PREFIX}_SIZEOF___FLOAT128} EQUAL 0))
if (NOT(${${HDF_PREFIX}_SIZEOF___FLOAT128} EQUAL ${max_real_fortran_sizeof})
AND NOT(${${HDF_PREFIX}_FORTRAN_SIZEOF_LONG_DOUBLE} EQUAL ${max_real_fortran_sizeof})
# account for the fact that the C compiler can have 16-byte __float128 and the fortran compiler only has 8-byte doubles,
# Remove the invalid kind from the list
if (${${HDF_PREFIX}_HAVE_FLOAT128})
if (NOT(16 EQUAL ${max_real_fortran_sizeof}) AND NOT(${${HDF_PREFIX}_FORTRAN_SIZEOF_LONG_DOUBLE} EQUAL ${max_real_fortran_sizeof})
# Account for the fact that the C compiler can have 16-byte __float128 and the fortran compiler only has 8-byte doubles,
# so we don't want to remove the 8-byte fortran doubles.
AND NOT(${PAC_FORTRAN_NATIVE_DOUBLE_SIZEOF} EQUAL ${max_real_fortran_sizeof}))
message (WARNING "
Expand Down
12 changes: 12 additions & 0 deletions config/cmake/HDFTests.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,18 @@
/* A simple test program to see if a function "works" */
#define SIMPLE_TEST(x) int main(void){ x; return 0; }

#ifdef HAVE___FLOAT128

/* Check if __float128 works (only used in the Fortran interface) */
int
main ()
{
__float128 x;

return 0;
}

#endif /* HAVE___FLOAT128 */

#ifdef HAVE_BUILTIN_EXPECT

Expand Down
86 changes: 66 additions & 20 deletions configure.ac
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Original file line number Diff line number Diff line change
Expand Up @@ -794,41 +794,87 @@ AC_MSG_RESULT([$HDF_FORTRAN])

if test "X$HDF_FORTRAN" = "Xyes"; then

## ----------------------------------------------------------------------
## Check for non-standard extension __FLOAT128
##
HAVE_FLOAT128=0
HAVE_QUADMATH=0
FLT128_DIG=0
LDBL_DIG=0
## ----------------------------------------------------------------------
## __float128 checks
##
## If __float128 exists and we can determine its precision, we will use
## it in the Fortran interface. The checks for this require that the
## precision be specified via a symbol named FLT128_DIG, which might be
## found in quadmath.h.
##
## The checks here are based on the GNU __float128 extension type from
## libquadmath, which is now part of gcc. Other compilers (clang, Intel)
## also expose __float128 and/or __float128 may be an alias for some
## other 128-bit floating point type.
##
## 128-bit floating-point math is usually handled in software and is thus
## orders of magnitude slower than hardware-supported floating-point math.
##
AC_MSG_CHECKING([if __float128 exists])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]],[[__float128 x; return 0;]])],
[HAVE___FLOAT128=1; AC_MSG_RESULT([yes])],
[HAVE___FLOAT128=0; AC_MSG_RESULT([no])]
)

## gcc puts symbols like FLT128_DIG in quadmath.h instead of float.h,
## so check for that before running the precision macro. Note that
## using AC_CHECK_HEADER instead of AC_CHECK_HEADERS keeps the
## H5_HAVE_QUADMATH_H symbol out of the public config header.
##
AC_CHECK_HEADER([quadmath.h], [INCLUDE_QUADMATH_H=1], [INCLUDE_QUADMATH_H=0])

## ----------------------------------------------------------------------
## Get the max decimal precision in C, checking both long double and
## __float128 (if available)
##
AC_MSG_CHECKING([maximum decimal precision for C])

AC_CHECK_SIZEOF([__float128])
AC_CHECK_SIZEOF([_Quad])
AC_CHECK_HEADERS([quadmath.h], [HAVE_QUADMATH=1], [])
MY_FLT128_DIG=0
MY_LDBL_DIG=0

## Macro to compare long double and __float128 to see which has higher precision
PAC_FC_LDBL_DIG

## Set results
if test "$MY_FLT128_DIG" -gt "$MY_LDBL_DIG" ; then
PAC_C_MAX_REAL_PRECISION=$MY_FLT128_DIG
PRECISION_TYPE="(__float128)"
else
PAC_C_MAX_REAL_PRECISION=$MY_LDBL_DIG
PRECISION_TYPE="(long double)"
fi
AC_MSG_RESULT([$PAC_C_MAX_REAL_PRECISION $PRECISION_TYPE])

## Store results in config file
AC_SUBST([PAC_C_MAX_REAL_PRECISION])
AC_DEFINE_UNQUOTED([PAC_C_MAX_REAL_PRECISION], $PAC_C_MAX_REAL_PRECISION, [Determine the maximum decimal precision in C])

## Are we going to use __float128?
AC_MSG_CHECKING([if __float128 will be used in the Fortran wrappers])

if test "$ac_cv_sizeof___float128" != 0 && test "$FLT128_DIG" != 0 ; then
AC_DEFINE([HAVE_FLOAT128], [1], [Determine if __float128 is available])
PAC_C_MAX_REAL_PRECISION=$FLT128_DIG
if test "$MY_FLT128_DIG" -gt "$MY_LDBL_DIG" ; then
AC_MSG_RESULT([yes])
AC_DEFINE([HAVE_FLOAT128], [1], [Determine if __float128 will be used in the Fortran wrappers])
else
PAC_C_MAX_REAL_PRECISION=$LDBL_DIG
## Can't use __float128, but write an undef line anyway
AC_MSG_RESULT([no])
AH_TEMPLATE([HAVE_FLOAT128], [Determine if __float128 will be used in the Fortran wrappers])
fi
AC_DEFINE_UNQUOTED([PAC_C_MAX_REAL_PRECISION], $PAC_C_MAX_REAL_PRECISION, [Determine the maximum decimal precision in C])
AC_MSG_RESULT([$PAC_C_MAX_REAL_PRECISION])

## ----------------------------------------------------------------------
## Define interface version
##
VERS_MAJOR=`cat $srcdir/src/H5public.h | sed -n 's/^#define H5_VERS_MAJOR //p'`
VERS_MINOR=`cat $srcdir/src/H5public.h | sed -n 's/^#define H5_VERS_MINOR //p'`
VERS_RELEASE=`cat $srcdir/src/H5public.h | sed -n 's/^#define H5_VERS_RELEASE //p'`
AC_DEFINE_UNQUOTED([VERS_MAJOR_TMP], $VERS_MAJOR, [Define major library version])
AC_DEFINE_UNQUOTED([VERS_MINOR_TMP], $VERS_MINOR, [Define minor library version])
AC_DEFINE_UNQUOTED([VERS_RELEASE_TMP], $VERS_RELEASE, [Define release library version])

## We will output an include file for Fortran, H5config_f.inc which
## contains various configure definitions used by the Fortran Library.
## Prepend H5_ to all macro names. This avoids name conflict between HDF5 macro
## names and those generated by another software package that uses the HDF5 library.
## We will output an include file for Fortran, H5config_f.inc which
## contains various configure definitions used by the Fortran Library.
## Prepend H5_ to all macro names. This avoids name conflict between HDF5 macro
## names and those generated by another software package that uses the HDF5 library.
AC_CONFIG_HEADERS([fortran/src/H5config_f.inc],
[cat fortran/src/H5config_f.inc | sed '1d;s%^/\* \(.*\) \*/%\1%;s/#define /#define H5_/;s/#undef /#undef H5_/' >fortran/src/H5config_f.inc.tmp; sed -i 's\_TMP\\g' fortran/src/H5config_f.inc.tmp; mv -f fortran/src/H5config_f.inc.tmp fortran/src/H5config_f.inc])

Expand Down
4 changes: 0 additions & 4 deletions fortran/test/tH5T_F03.F90
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1090,10 +1090,8 @@ SUBROUTINE test_h5kind_to_type(total_error)
CALL check("H5Dcreate_f",error, total_error)
CALL H5Dcreate_f(file_id, dsetnamer8, h5kind_to_type(real_kind_15,H5_REAL_KIND), dspace_id, dset_idr8, error)
CALL check("H5Dcreate_f",error, total_error)
!#ifdef H5_HAVE_FLOAT128
CALL H5Dcreate_f(file_id, dsetnamer16, h5kind_to_type(real_kind_31,H5_REAL_KIND), dspace_id, dset_idr16, error)
CALL check("H5Dcreate_f",error, total_error)
!#endif
!
! Write the dataset.
!
Expand Down Expand Up @@ -1123,11 +1121,9 @@ SUBROUTINE test_h5kind_to_type(total_error)
f_ptr = C_LOC(dset_data_r15(1))
CALL h5dwrite_f(dset_idr8, h5kind_to_type(real_kind_15,H5_REAL_KIND), f_ptr, error)
CALL check("H5Dwrite_f",error, total_error)
!#ifdef H5_HAVE_FLOAT128
f_ptr = C_LOC(dset_data_r31(1))
CALL h5dwrite_f(dset_idr16, h5kind_to_type(real_kind_31,H5_REAL_KIND), f_ptr, error)
CALL check("H5Dwrite_f",error, total_error)
!#endif
!
! Close the file
!
Expand Down
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