NEWS.stable: log cherry-pick [e446f25]->[c092018] relocatable-shell: Update suggested...

[gnulib.git] / m4 / sqrtl.m4

diff --git a/m4/sqrtl.m4 b/m4/sqrtl.m4
index aa8522b..a730290 100644 (file)
--- a/m4/sqrtl.m4
+++ b/m4/sqrtl.m4
@@ -1,5 +1,5 @@
-# sqrtl.m4 serial 5
-dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
+# sqrtl.m4 serial 9
+dnl Copyright (C) 2010-2014 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.
@@ -7,6 +7,8 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_SQRTL],
 [
   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
+
   dnl Persuade glibc <math.h> to declare sqrtl().
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
@@ -20,8 +22,10 @@ AC_DEFUN([gl_FUNC_SQRTL],
              # define __NO_MATH_INLINES 1 /* for glibc */
              #endif
              #include <math.h>
+             long double (*funcptr) (long double) = sqrtl;
              long double x;]],
-           [[return sqrtl (x) > 0.4;]])],
+           [[return funcptr (x) > 0.4
+                    || sqrtl (x) > 0.4;]])],
         [gl_cv_func_sqrtl_no_libm=yes],
         [gl_cv_func_sqrtl_no_libm=no])
     ])
@@ -37,8 +41,10 @@ AC_DEFUN([gl_FUNC_SQRTL],
                # define __NO_MATH_INLINES 1 /* for glibc */
                #endif
                #include <math.h>
+               long double (*funcptr) (long double) = sqrtl;
                long double x;]],
-             [[return sqrtl (x) > 0.4;]])],
+             [[return funcptr (x) > 0.4
+                      || sqrtl (x) > 0.4;]])],
           [gl_cv_func_sqrtl_in_libm=yes],
           [gl_cv_func_sqrtl_in_libm=no])
         LIBS="$save_LIBS"
@@ -50,36 +56,107 @@ AC_DEFUN([gl_FUNC_SQRTL],
   if test $gl_cv_func_sqrtl_no_libm = yes \
      || test $gl_cv_func_sqrtl_in_libm = yes; then
     dnl Also check whether it's declared.
-    dnl MacOS X 10.3 has sqrtl() in libc but doesn't declare it in <math.h>.
+    dnl Mac OS X 10.3 has sqrtl() in libc but doesn't declare it in <math.h>.
     AC_CHECK_DECL([sqrtl], , [HAVE_DECL_SQRTL=0], [[#include <math.h>]])
+
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $SQRTL_LIBM"
+    gl_FUNC_SQRTL_WORKS
+    LIBS="$save_LIBS"
+    case "$gl_cv_func_sqrtl_works" in
+      *yes) ;;
+      *) REPLACE_SQRTL=1 ;;
+    esac
   else
     HAVE_DECL_SQRTL=0
     HAVE_SQRTL=0
+  fi
+  if test $HAVE_SQRTL = 0 || test $REPLACE_SQRTL = 1; then
     dnl Find libraries needed to link lib/sqrtl.c.
-    AC_REQUIRE([gl_FUNC_ISNANL])
-    AC_REQUIRE([gl_FUNC_FREXPL])
-    AC_REQUIRE([gl_FUNC_LDEXPL])
-    AC_REQUIRE([gl_FUNC_SQRT])
-    dnl Append $ISNANL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
-    case " $SQRTL_LIBM " in
-      *" $ISNANL_LIBM "*) ;;
-      *) SQRTL_LIBM="$SQRTL_LIBM $ISNANL_LIBM" ;;
-    esac
-    dnl Append $FREXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
-    case " $SQRTL_LIBM " in
-      *" $FREXPL_LIBM "*) ;;
-      *) SQRTL_LIBM="$SQRTL_LIBM $FREXPL_LIBM" ;;
-    esac
-    dnl Append $LDEXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
-    case " $SQRTL_LIBM " in
-      *" $LDEXPL_LIBM "*) ;;
-      *) SQRTL_LIBM="$SQRTL_LIBM $LDEXPL_LIBM" ;;
-    esac
-    dnl Append $SQRT_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
-    case " $SQRTL_LIBM " in
-      *" $SQRT_LIBM "*) ;;
-      *) SQRTL_LIBM="$SQRTL_LIBM $SQRT_LIBM" ;;
-    esac
+    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
+      AC_REQUIRE([gl_FUNC_SQRT])
+      SQRTL_LIBM="$SQRT_LIBM"
+    else
+      AC_REQUIRE([gl_FUNC_ISNANL])
+      AC_REQUIRE([gl_FUNC_FREXPL])
+      AC_REQUIRE([gl_FUNC_LDEXPL])
+      AC_REQUIRE([gl_FUNC_SQRT])
+      dnl Append $ISNANL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
+      case " $SQRTL_LIBM " in
+        *" $ISNANL_LIBM "*) ;;
+        *) SQRTL_LIBM="$SQRTL_LIBM $ISNANL_LIBM" ;;
+      esac
+      dnl Append $FREXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
+      case " $SQRTL_LIBM " in
+        *" $FREXPL_LIBM "*) ;;
+        *) SQRTL_LIBM="$SQRTL_LIBM $FREXPL_LIBM" ;;
+      esac
+      dnl Append $LDEXPL_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
+      case " $SQRTL_LIBM " in
+        *" $LDEXPL_LIBM "*) ;;
+        *) SQRTL_LIBM="$SQRTL_LIBM $LDEXPL_LIBM" ;;
+      esac
+      dnl Append $SQRT_LIBM to SQRTL_LIBM, avoiding gratuitous duplicates.
+      case " $SQRTL_LIBM " in
+        *" $SQRT_LIBM "*) ;;
+        *) SQRTL_LIBM="$SQRTL_LIBM $SQRT_LIBM" ;;
+      esac
+    fi
   fi
   AC_SUBST([SQRTL_LIBM])
 ])
+
+dnl Test whether sqrtl() works.
+dnl On OpenBSD 5.1/SPARC, sqrtl(8.1974099812331540680810141969554806865L) has
+dnl rounding errors that eat up the last 8 to 9 decimal digits.
+AC_DEFUN([gl_FUNC_SQRTL_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether sqrtl works], [gl_cv_func_sqrtl_works],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <float.h>
+#include <math.h>
+#ifndef sqrtl /* for AIX */
+extern
+#ifdef __cplusplus
+"C"
+#endif
+long double sqrtl (long double);
+#endif
+static long double
+my_ldexpl (long double x, int d)
+{
+  for (; d > 0; d--)
+    x *= 2.0L;
+  for (; d < 0; d++)
+    x *= 0.5L;
+  return x;
+}
+volatile long double x;
+volatile long double y;
+long double z;
+int main ()
+{
+  x = 8.1974099812331540680810141969554806865L;
+  y = sqrtl (x);
+  z = y * y - x;
+  z = my_ldexpl (z, LDBL_MANT_DIG);
+  if (z < 0)
+    z = - z;
+  if (z > 100.0L)
+    return 1;
+  return 0;
+}
+]])],
+        [gl_cv_func_sqrtl_works=yes],
+        [gl_cv_func_sqrtl_works=no],
+        [case "$host_os" in
+           openbsd*) gl_cv_func_sqrtl_works="guessing no";;
+           *)        gl_cv_func_sqrtl_works="guessing yes";;
+         esac
+        ])
+    ])
+])