mirror of
https://github.com/postgres/postgres.git
synced 2025-04-27 22:56:53 +03:00
Extend configure's __int128 test to check for a known gcc bug.
On Sparc64, use of __attribute__(aligned(8)) with __int128 causes faulty code generation in gcc versions at least through 5.5.0. We can work around that by disabling use of __int128, so teach configure to test for the bug. This solution doesn't fix things for the case of cross-compiling with a buggy compiler; to support that nicely, we'd need to add a manual disable switch. Unless more such cases turn up, it doesn't seem worth the work. Affected users could always edit pg_config.h manually. In passing, fix some typos in the existing configure test for __int128. They're harmless because we only compile that code not run it, but they're still confusing for anyone looking at it closely. This is needed in support of commit 751804998, so back-patch to 9.5 as that was. Marina Polyakova, Victor Wagner, Tom Lane Discussion: https://postgr.es/m/0d3a9fa264cebe1cb9966f37b7c06e86@postgrespro.ru
This commit is contained in:
Tom Lane
parent
4a81c02297
commit
456cab29df
@ -106,29 +106,61 @@ AC_DEFUN([PGAC_TYPE_128BIT_INT],
|
||||
[AC_CACHE_CHECK([for __int128], [pgac_cv__128bit_int],
|
||||
[AC_LINK_IFELSE([AC_LANG_PROGRAM([
|
||||
/*
|
||||
* We don't actually run this test, just link it to verify that any support
|
||||
* functions needed for __int128 are present.
|
||||
*
|
||||
* These are globals to discourage the compiler from folding all the
|
||||
* arithmetic tests down to compile-time constants. We do not have
|
||||
* convenient support for 64bit literals at this point...
|
||||
* convenient support for 128bit literals at this point...
|
||||
*/
|
||||
__int128 a = 48828125;
|
||||
__int128 b = 97656255;
|
||||
__int128 b = 97656250;
|
||||
],[
|
||||
__int128 c,d;
|
||||
a = (a << 12) + 1; /* 200000000001 */
|
||||
b = (b << 12) + 5; /* 400000000005 */
|
||||
/* use the most relevant arithmetic ops */
|
||||
/* try the most relevant arithmetic ops */
|
||||
c = a * b;
|
||||
d = (c + b) / b;
|
||||
/* return different values, to prevent optimizations */
|
||||
/* must use the results, else compiler may optimize arithmetic away */
|
||||
if (d != a+1)
|
||||
return 0;
|
||||
return 1;
|
||||
return 1;
|
||||
])],
|
||||
[pgac_cv__128bit_int=yes],
|
||||
[pgac_cv__128bit_int=no])])
|
||||
if test x"$pgac_cv__128bit_int" = xyes ; then
|
||||
AC_DEFINE(PG_INT128_TYPE, __int128, [Define to the name of a signed 128-bit integer type.])
|
||||
AC_CHECK_ALIGNOF(PG_INT128_TYPE)
|
||||
# Use of non-default alignment with __int128 tickles bugs in some compilers.
|
||||
# If not cross-compiling, we can test for bugs and disable use of __int128
|
||||
# with buggy compilers. If cross-compiling, hope for the best.
|
||||
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83925
|
||||
AC_CACHE_CHECK([for __int128 alignment bug], [pgac_cv__128bit_int_bug],
|
||||
[AC_RUN_IFELSE([AC_LANG_PROGRAM([
|
||||
/* This must match the corresponding code in c.h: */
|
||||
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
|
||||
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
|
||||
#endif
|
||||
typedef __int128 int128a
|
||||
#if defined(pg_attribute_aligned)
|
||||
pg_attribute_aligned(8)
|
||||
#endif
|
||||
;
|
||||
int128a holder;
|
||||
void pass_by_val(void *buffer, int128a par) { holder = par; }
|
||||
],[
|
||||
long int i64 = 97656225L << 12;
|
||||
int128a q;
|
||||
pass_by_val(main, (int128a) i64);
|
||||
q = (int128a) i64;
|
||||
if (q != holder)
|
||||
return 1;
|
||||
])],
|
||||
[pgac_cv__128bit_int_bug=ok],
|
||||
[pgac_cv__128bit_int_bug=broken],
|
||||
[pgac_cv__128bit_int_bug="assuming ok"])])
|
||||
if test x"$pgac_cv__128bit_int_bug" != xbroken ; then
|
||||
AC_DEFINE(PG_INT128_TYPE, __int128, [Define to the name of a signed 128-bit integer type.])
|
||||
AC_CHECK_ALIGNOF(PG_INT128_TYPE)
|
||||
fi
|
||||
fi])# PGAC_TYPE_128BIT_INT
|
||||
|
||||
|
||||
|
||||
72
configure
vendored
72
configure
vendored
@ -14355,12 +14355,15 @@ else
|
||||
/* end confdefs.h. */
|
||||
|
||||
/*
|
||||
* We don't actually run this test, just link it to verify that any support
|
||||
* functions needed for __int128 are present.
|
||||
*
|
||||
* These are globals to discourage the compiler from folding all the
|
||||
* arithmetic tests down to compile-time constants. We do not have
|
||||
* convenient support for 64bit literals at this point...
|
||||
* convenient support for 128bit literals at this point...
|
||||
*/
|
||||
__int128 a = 48828125;
|
||||
__int128 b = 97656255;
|
||||
__int128 b = 97656250;
|
||||
|
||||
int
|
||||
main ()
|
||||
@ -14369,13 +14372,12 @@ main ()
|
||||
__int128 c,d;
|
||||
a = (a << 12) + 1; /* 200000000001 */
|
||||
b = (b << 12) + 5; /* 400000000005 */
|
||||
/* use the most relevant arithmetic ops */
|
||||
/* try the most relevant arithmetic ops */
|
||||
c = a * b;
|
||||
d = (c + b) / b;
|
||||
/* return different values, to prevent optimizations */
|
||||
/* must use the results, else compiler may optimize arithmetic away */
|
||||
if (d != a+1)
|
||||
return 0;
|
||||
return 1;
|
||||
return 1;
|
||||
|
||||
;
|
||||
return 0;
|
||||
@ -14392,10 +14394,65 @@ fi
|
||||
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv__128bit_int" >&5
|
||||
$as_echo "$pgac_cv__128bit_int" >&6; }
|
||||
if test x"$pgac_cv__128bit_int" = xyes ; then
|
||||
# Use of non-default alignment with __int128 tickles bugs in some compilers.
|
||||
# If not cross-compiling, we can test for bugs and disable use of __int128
|
||||
# with buggy compilers. If cross-compiling, hope for the best.
|
||||
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83925
|
||||
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __int128 alignment bug" >&5
|
||||
$as_echo_n "checking for __int128 alignment bug... " >&6; }
|
||||
if ${pgac_cv__128bit_int_bug+:} false; then :
|
||||
$as_echo_n "(cached) " >&6
|
||||
else
|
||||
if test "$cross_compiling" = yes; then :
|
||||
pgac_cv__128bit_int_bug="assuming ok"
|
||||
else
|
||||
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
|
||||
/* end confdefs.h. */
|
||||
|
||||
/* This must match the corresponding code in c.h: */
|
||||
#if defined(__GNUC__) || defined(__SUNPRO_C) || defined(__IBMC__)
|
||||
#define pg_attribute_aligned(a) __attribute__((aligned(a)))
|
||||
#endif
|
||||
typedef __int128 int128a
|
||||
#if defined(pg_attribute_aligned)
|
||||
pg_attribute_aligned(8)
|
||||
#endif
|
||||
;
|
||||
int128a holder;
|
||||
void pass_by_val(void *buffer, int128a par) { holder = par; }
|
||||
|
||||
int
|
||||
main ()
|
||||
{
|
||||
|
||||
long int i64 = 97656225L << 12;
|
||||
int128a q;
|
||||
pass_by_val(main, (int128a) i64);
|
||||
q = (int128a) i64;
|
||||
if (q != holder)
|
||||
return 1;
|
||||
|
||||
;
|
||||
return 0;
|
||||
}
|
||||
_ACEOF
|
||||
if ac_fn_c_try_run "$LINENO"; then :
|
||||
pgac_cv__128bit_int_bug=ok
|
||||
else
|
||||
pgac_cv__128bit_int_bug=broken
|
||||
fi
|
||||
rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
|
||||
conftest.$ac_objext conftest.beam conftest.$ac_ext
|
||||
fi
|
||||
|
||||
fi
|
||||
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv__128bit_int_bug" >&5
|
||||
$as_echo "$pgac_cv__128bit_int_bug" >&6; }
|
||||
if test x"$pgac_cv__128bit_int_bug" != xbroken ; then
|
||||
|
||||
$as_echo "#define PG_INT128_TYPE __int128" >>confdefs.h
|
||||
|
||||
# The cast to long int works around a bug in the HP C Compiler,
|
||||
# The cast to long int works around a bug in the HP C Compiler,
|
||||
# see AC_CHECK_SIZEOF for more information.
|
||||
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking alignment of PG_INT128_TYPE" >&5
|
||||
$as_echo_n "checking alignment of PG_INT128_TYPE... " >&6; }
|
||||
@ -14430,6 +14487,7 @@ cat >>confdefs.h <<_ACEOF
|
||||
_ACEOF
|
||||
|
||||
|
||||
fi
|
||||
fi
|
||||
|
||||
# Check for various atomic operations now that we have checked how to declare
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user