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Use a more bulletproof test for whether finite() and isinf() are present.

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It seems that recent gcc versions can optimize away calls to these functions
even when the functions do not exist on the platform, resulting in a bogus
positive result.  Avoid this by using a non-constant argument and ensuring
that the function result is not simply discarded.  Per report from
François Laupretre.
This commit is contained in:
Tom Lane 2006-01-12 19:23:22 +00:00
parent 9484e14c5c
commit db0558c113
2 changed files with 18 additions and 10 deletions
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10
configure vendored
View File

@ -14202,7 +14202,6 @@ fi
# do this one the hard way in case isinf() is a macro
echo "$as_me:$LINENO: checking for isinf" >&5
echo $ECHO_N "checking for isinf... $ECHO_C" >&6
if test "${ac_cv_func_isinf+set}" = set; then
@ -14214,12 +14213,14 @@ _ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <math.h>
double glob_double;
int
main ()
{
double x = 0.0; int res = isinf(x);
return isinf(glob_double) ? 0 : 1;
;
return 0;
}
@ -15102,11 +15103,14 @@ _ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
#include <math.h>
double glob_double;
int
main ()
{
int dummy=finite(1.0);
return finite(glob_double) ? 0 : 1;
;
return 0;
}

18
configure.in
View File

@ -1,5 +1,5 @@
dnl Process this file with autoconf to produce a configure script.
dnl $PostgreSQL: pgsql/configure.in,v 1.441 2006/01/05 03:01:32 momjian Exp $
dnl $PostgreSQL: pgsql/configure.in,v 1.442 2006/01/12 19:23:22 tgl Exp $
dnl
dnl Developers, please strive to achieve this order:
dnl
@ -892,12 +892,13 @@ fi
AC_CHECK_DECLS([snprintf, vsnprintf])
# do this one the hard way in case isinf() is a macro
dnl Cannot use AC_CHECK_FUNC because isinf may be a macro
AC_CACHE_CHECK([for isinf], ac_cv_func_isinf,
[AC_TRY_LINK(
[#include <math.h>
[AC_TRY_LINK([
#include <math.h>
double glob_double;
],
[double x = 0.0; int res = isinf(x);],
[return isinf(glob_double) ? 0 : 1;],
[ac_cv_func_isinf=yes],
[ac_cv_func_isinf=no])])
@ -963,8 +964,11 @@ fi
dnl Cannot use AC_CHECK_FUNC because finite may be a macro
AC_MSG_CHECKING(for finite)
AC_TRY_LINK([#include <math.h>],
[int dummy=finite(1.0);],
AC_TRY_LINK([
#include <math.h>
double glob_double;
],
[return finite(glob_double) ? 0 : 1;],
[AC_DEFINE(HAVE_FINITE, 1, [Define to 1 if you have finite().])
AC_MSG_RESULT(yes)],
[AC_MSG_RESULT(no)])