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Diffstat (limited to 'gnulib/m4/fma.m4')
| m--------- | gnulib | 0 | ||||
| -rw-r--r-- | gnulib/m4/fma.m4 | 166 |
2 files changed, 166 insertions, 0 deletions
diff --git a/gnulib b/gnulib deleted file mode 160000 -Subproject 443bc5ffcf7429e557f4a371b0661abe98ddbc1 diff --git a/gnulib/m4/fma.m4 b/gnulib/m4/fma.m4 new file mode 100644 index 0000000..3ce3f9a --- /dev/null +++ b/gnulib/m4/fma.m4 @@ -0,0 +1,166 @@ +# fma.m4 serial 1 +dnl Copyright (C) 2011 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +AC_DEFUN([gl_FUNC_FMA], +[ + AC_REQUIRE([gl_MATH_H_DEFAULTS]) + + dnl Determine FMA_LIBM. + gl_MATHFUNC([fma], [double], [(double, double, double)]) + if test $gl_cv_func_fma_no_libm = yes \ + || test $gl_cv_func_fma_in_libm = yes; then + gl_FUNC_FMA_WORKS + case "$gl_cv_func_fma_works" in + *no) REPLACE_FMA=1 ;; + esac + else + HAVE_FMA=0 + fi + if test $HAVE_FMA = 0 || test $REPLACE_FMA = 1; then + dnl Find libraries needed to link lib/fmal.c. + AC_REQUIRE([gl_FUNC_FREXP]) + AC_REQUIRE([gl_FUNC_LDEXP]) + AC_REQUIRE([gl_FUNC_FEGETROUND]) + FMA_LIBM= + dnl Append $FREXP_LIBM to FMA_LIBM, avoiding gratuitous duplicates. + case " $FMA_LIBM " in + *" $FREXP_LIBM "*) ;; + *) FMA_LIBM="$FMA_LIBM $FREXP_LIBM" ;; + esac + dnl Append $LDEXP_LIBM to FMA_LIBM, avoiding gratuitous duplicates. + case " $FMA_LIBM " in + *" $LDEXP_LIBM "*) ;; + *) FMA_LIBM="$FMA_LIBM $LDEXP_LIBM" ;; + esac + dnl Append $FEGETROUND_LIBM to FMA_LIBM, avoiding gratuitous duplicates. + case " $FMA_LIBM " in + *" $FEGETROUND_LIBM "*) ;; + *) FMA_LIBM="$FMA_LIBM $FEGETROUND_LIBM" ;; + esac + fi + AC_SUBST([FMA_LIBM]) +]) + +dnl Test whether fma() has any of the 7 known bugs of glibc 2.11.3 on x86_64. +AC_DEFUN([gl_FUNC_FMA_WORKS], +[ + AC_REQUIRE([AC_PROG_CC]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_REQUIRE([gl_FUNC_LDEXP]) + save_LIBS="$LIBS" + LIBS="$LIBS $FMA_LIBM $LDEXP_LIBM" + AC_CACHE_CHECK([whether fma works], [gl_cv_func_fma_works], + [ + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#include <float.h> +#include <math.h> +double p0 = 0.0; +int main() +{ + int failed_tests = 0; + /* These tests fail with glibc 2.11.3 on x86_64. */ + { + volatile double x = 1.5; /* 3 * 2^-1 */ + volatile double y = x; + volatile double z = ldexp (1.0, DBL_MANT_DIG + 1); /* 2^54 */ + /* x * y + z with infinite precision: 2^54 + 9 * 2^-2. + Lies between (2^52 + 0) * 2^2 and (2^52 + 1) * 2^2 + and is closer to (2^52 + 1) * 2^2, therefore the rounding + must round up and produce (2^52 + 1) * 2^2. */ + volatile double expected = z + 4.0; + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 1; + } + { + volatile double x = 1.25; /* 2^0 + 2^-2 */ + volatile double y = - x; + volatile double z = ldexp (1.0, DBL_MANT_DIG + 1); /* 2^54 */ + /* x * y + z with infinite precision: 2^54 - 2^0 - 2^-1 - 2^-4. + Lies between (2^53 - 1) * 2^1 and 2^53 * 2^1 + and is closer to (2^53 - 1) * 2^1, therefore the rounding + must round down and produce (2^53 - 1) * 2^1. */ + volatile double expected = (ldexp (1.0, DBL_MANT_DIG) - 1.0) * 2.0; + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 2; + } + { + volatile double x = 1.0 + ldexp (1.0, 1 - DBL_MANT_DIG); /* 2^0 + 2^-52 */ + volatile double y = x; + volatile double z = 4.0; /* 2^2 */ + /* x * y + z with infinite precision: 2^2 + 2^0 + 2^-51 + 2^-104. + Lies between (2^52 + 2^50) * 2^-50 and (2^52 + 2^50 + 1) * 2^-50 + and is closer to (2^52 + 2^50 + 1) * 2^-50, therefore the rounding + must round up and produce (2^52 + 2^50 + 1) * 2^-50. */ + volatile double expected = 4.0 + 1.0 + ldexp (1.0, 3 - DBL_MANT_DIG); + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 4; + } + { + volatile double x = 1.0 + ldexp (1.0, 1 - DBL_MANT_DIG); /* 2^0 + 2^-52 */ + volatile double y = - x; + volatile double z = 8.0; /* 2^3 */ + /* x * y + z with infinite precision: 2^2 + 2^1 + 2^0 - 2^-51 - 2^-104. + Lies between (2^52 + 2^51 + 2^50 - 1) * 2^-50 and + (2^52 + 2^51 + 2^50) * 2^-50 and is closer to + (2^52 + 2^51 + 2^50 - 1) * 2^-50, therefore the rounding + must round down and produce (2^52 + 2^51 + 2^50 - 1) * 2^-50. */ + volatile double expected = 7.0 - ldexp (1.0, 3 - DBL_MANT_DIG); + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 8; + } + { + volatile double x = 1.25; /* 2^0 + 2^-2 */ + volatile double y = - 0.75; /* - 2^0 + 2^-2 */ + volatile double z = ldexp (1.0, DBL_MANT_DIG); /* 2^53 */ + /* x * y + z with infinite precision: 2^53 - 2^0 + 2^-4. + Lies between (2^53 - 2^0) and 2^53 and is closer to (2^53 - 2^0), + therefore the rounding must round down and produce (2^53 - 2^0). */ + volatile double expected = ldexp (1.0, DBL_MANT_DIG) - 1.0; + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 16; + } + if ((DBL_MANT_DIG % 2) == 1) + { + volatile double x = 1.0 + ldexp (1.0, - (DBL_MANT_DIG + 1) / 2); /* 2^0 + 2^-27 */ + volatile double y = 1.0 - ldexp (1.0, - (DBL_MANT_DIG + 1) / 2); /* 2^0 - 2^-27 */ + volatile double z = - ldexp (1.0, DBL_MIN_EXP - DBL_MANT_DIG); /* - 2^-1074 */ + /* x * y + z with infinite precision: 2^0 - 2^-54 - 2^-1074. + Lies between (2^53 - 1) * 2^-53 and 2^53 * 2^-53 and is closer to + (2^53 - 1) * 2^-53, therefore the rounding must round down and + produce (2^53 - 1) * 2^-53. */ + volatile double expected = 1.0 - ldexp (1.0, - DBL_MANT_DIG); + volatile double result = fma (x, y, z); + if (result != expected) + failed_tests |= 32; + } + { + double minus_inf = -1.0 / p0; + volatile double x = ldexp (1.0, DBL_MAX_EXP - 1); + volatile double y = ldexp (1.0, DBL_MAX_EXP - 1); + volatile double z = minus_inf; + volatile double result = fma (x, y, z); + if (!(result == minus_inf)) + failed_tests |= 64; + } + return failed_tests; +}]])], + [gl_cv_func_fma_works=yes], + [gl_cv_func_fma_works=no], + [dnl Guess no, even on glibc systems. + gl_cv_func_fma_works="guessing no" + ]) + ]) + LIBS="$save_LIBS" +]) + +# Prerequisites of lib/fma.c. +AC_DEFUN([gl_PREREQ_FMA], [:]) |