X-Git-Url: https://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fexpm1f.m4;h=04a0d7279aca440d886b497f97ef6401dea29565;hb=85ab65259ed73d4d6e12f13c3f0882bdbb9d1cd6;hp=f78262a47b7682ad27b7dfe98c924a0b0f07effd;hpb=fef5744cfb2fe5d6241e66a8e736f6926e7ea621;p=gnulib.git

diff --git a/m4/expm1f.m4 b/m4/expm1f.m4
index f78262a47..04a0d7279 100644
--- a/m4/expm1f.m4
+++ b/m4/expm1f.m4
@@ -1,4 +1,4 @@
-# expm1f.m4 serial 1
+# expm1f.m4 serial 2
 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,
@@ -20,10 +20,52 @@ AC_DEFUN([gl_FUNC_EXPM1F],
   LIBS="$save_LIBS"
   if test $ac_cv_func_expm1f = yes; then
     EXPM1F_LIBM="$EXPM1_LIBM"
+    save_LIBS="$LIBS"
+    LIBS="$LIBS $EXPM1F_LIBM"
+    gl_FUNC_EXPM1F_WORKS
+    LIBS="$save_LIBS"
+    case "$gl_cv_func_expm1f_works" in
+      *yes) ;;
+      *) REPLACE_EXPM1F=1 ;;
+    esac
   else
     HAVE_EXPM1F=0
+  fi
+  if test $HAVE_EXPM1F = 0 || test $REPLACE_EXPM1F = 1; then
     dnl Find libraries needed to link lib/expm1f.c.
     EXPM1F_LIBM="$EXPM1_LIBM"
   fi
   AC_SUBST([EXPM1F_LIBM])
 ])
+
+dnl Test whether expm1f() works.
+dnl On IRIX 6.5, for arguments <= -17.32868, it returns -5.6295e14.
+AC_DEFUN([gl_FUNC_EXPM1F_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether expm1f works], [gl_cv_func_expm1f_works],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <math.h>
+volatile float x;
+float y;
+int main ()
+{
+  x = -100.0f;
+  y = expm1f (x);
+  if (y < -1.0f)
+    return 1;
+  return 0;
+}
+]])],
+        [gl_cv_func_expm1f_works=yes],
+        [gl_cv_func_expm1f_works=no],
+        [case "$host_os" in
+           irix*) gl_cv_func_expm1f_works="guessing no";;
+           *)     gl_cv_func_expm1f_works="guessing yes";;
+         esac
+        ])
+    ])
+])