New module 'fabsl'.

* lib/math.in.h (fabsl): New declaration.
* lib/fabsl.c: New file.
* m4/fabsl.m4: New file.
* m4/math_h.m4 (gl_MATH_H): Test whether fabsl is declared.
(gl_MATH_H_DEFAULTS): Initialize GNULIB_FABSL, HAVE_FABSL,
REPLACE_FABSL.
* modules/math (Makefile.am): Substitute GNULIB_FABSL, HAVE_FABSL,
REPLACE_FABSL.
* modules/fabsl: New file.
* doc/posix-functions/fabsl.texi: Mention the new module.

2 files changed, 76 insertions, 2 deletions

diff --git a/m4/fabsl.m4 b/m4/fabsl.m4
new file mode 100644
index 0000000000..fa4825bb36
--- /dev/null
+++ b/m4/fabsl.m4
@@ -0,0 +1,71 @@
+# fabsl.m4 serial 1
+dnl Copyright (C) 2011-2012 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_FABSL],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+
+  dnl Determine FABSL_LIBM.
+  gl_MATHFUNC([fabsl], [long double], [(long double)])
+  if test $gl_cv_func_fabsl_no_libm = yes \
+     || test $gl_cv_func_fabsl_in_libm = yes; then
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $FABSL_LIBM"
+    gl_FUNC_FABSL_WORKS
+    LIBS="$save_LIBS"
+    case "$gl_cv_func_fabsl_works" in
+      *yes) ;;
+      *) REPLACE_FABSL=1 ;;
+    esac
+  else
+    HAVE_FABSL=0
+  fi
+  if test $HAVE_FABSL = 0 || test $REPLACE_FABSL = 1; then
+    dnl Find libraries needed to link lib/fabsl.c.
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_FABS])
+      FABSL_LIBM="$FABS_LIBM"
+    else
+      FABSL_LIBM=
+    fi
+  fi
+  AC_SUBST([FABSL_LIBM])
+])
+
+dnl Test whether fabsl() works on a minus zero.
+dnl On IRIX 6.5, with gcc 4.2.4 and without -fno-builtin-fabsl, the value is a
+dnl minus zero rather than a positive zero.
+AC_DEFUN([gl_FUNC_FABSL_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether fabsl works], [gl_cv_func_fabsl_works],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <float.h>
+#include <math.h>
+#include <string.h>
+volatile long double x;
+long double y;
+long double zero = 0.0L;
+int main ()
+{
+  x = - (LDBL_MIN * LDBL_MIN * LDBL_MIN);
+  y = fabsl (x);
+  return (memcmp (&y, &zero, sizeof y) != 0);
+}
+]])],
+        [gl_cv_func_fabsl_works=yes],
+        [gl_cv_func_fabsl_works=no],
+        [case "$host_os" in
+           irix*) gl_cv_func_fabsl_works="guessing no";;
+           *)     gl_cv_func_fabsl_works="guessing yes";;
+         esac
+        ])
+    ])
+])
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 5d7d52bbab..2dad99970a 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 56
+# math_h.m4 serial 57
 dnl Copyright (C) 2007-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -41,7 +41,7 @@ AC_DEFUN([gl_MATH_H],
   gl_WARN_ON_USE_PREPARE([[#include <math.h>]],
     [acosf acosl asinf asinl atanf atanl
      ceilf ceill copysign copysignf copysignl cosf cosl coshf
-     expf expl fabsf floorf floorl fma fmaf fmal fmodf frexpf frexpl
+     expf expl fabsf fabsl floorf floorl fma fmaf fmal fmodf frexpf frexpl
      ldexpf ldexpl logb logf logl log10f modff powf
      rint rintf rintl round roundf roundl sinf sinl sinhf sqrtf sqrtl
      tanf tanl tanhf trunc truncf truncl])
@@ -77,6 +77,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   GNULIB_EXPF=0;      AC_SUBST([GNULIB_EXPF])
   GNULIB_EXPL=0;      AC_SUBST([GNULIB_EXPL])
   GNULIB_FABSF=0;     AC_SUBST([GNULIB_FABSF])
+  GNULIB_FABSL=0;     AC_SUBST([GNULIB_FABSL])
   GNULIB_FLOOR=0;     AC_SUBST([GNULIB_FLOOR])
   GNULIB_FLOORF=0;    AC_SUBST([GNULIB_FLOORF])
   GNULIB_FLOORL=0;    AC_SUBST([GNULIB_FLOORL])
@@ -136,6 +137,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   HAVE_EXPF=1;                 AC_SUBST([HAVE_EXPF])
   HAVE_EXPL=1;                 AC_SUBST([HAVE_EXPL])
   HAVE_FABSF=1;                AC_SUBST([HAVE_FABSF])
+  HAVE_FABSL=1;                AC_SUBST([HAVE_FABSL])
   HAVE_FMA=1;                  AC_SUBST([HAVE_FMA])
   HAVE_FMAF=1;                 AC_SUBST([HAVE_FMAF])
   HAVE_FMAL=1;                 AC_SUBST([HAVE_FMAL])
@@ -186,6 +188,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   REPLACE_CEIL=0;              AC_SUBST([REPLACE_CEIL])
   REPLACE_CEILF=0;             AC_SUBST([REPLACE_CEILF])
   REPLACE_CEILL=0;             AC_SUBST([REPLACE_CEILL])
+  REPLACE_FABSL=0;             AC_SUBST([REPLACE_FABSL])
   REPLACE_FLOOR=0;             AC_SUBST([REPLACE_FLOOR])
   REPLACE_FLOORF=0;            AC_SUBST([REPLACE_FLOORF])
   REPLACE_FLOORL=0;            AC_SUBST([REPLACE_FLOORL])