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Disable -faggressive-loop-optimizations in gcc 4.8+ for pre-9.2 branches.

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With this optimization flag enabled, recent versions of gcc can generate
incorrect code that assumes variable-length arrays (such as oidvector)
are actually fixed-length because they're embedded in some larger struct.
The known instance of this problem was fixed in 9.2 and up by commit
8137f2c323 and followon work, which hides
actually-variable-length catalog fields from the compiler altogether.
And we plan to gradually convert variable-length fields to official
"flexible array member" notation over time, which should prevent this type
of bug from reappearing as gcc gets smarter.  We're not going to try to
back-port those changes into older branches, though, so apply this
band-aid instead.

Andres Freund
This commit is contained in:
Tom Lane
2013-08-21 18:31:51 -04:00
parent 8e0b7d2219
commit e9e387a5b1
2 changed files with 55 additions and 0 deletions
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52
configure vendored
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@ -4250,6 +4250,58 @@ sed 's/^/| /' conftest.$ac_ext >&5
$as_echo "no" >&6; }
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
# Disable loop optimizations that get confused by variable-length struct
# declarations in gcc 4.8+
{ $as_echo "$as_me:$LINENO: checking if $CC supports -fno-aggressive-loop-optimizations" >&5
$as_echo_n "checking if $CC supports -fno-aggressive-loop-optimizations... " >&6; }
pgac_save_CFLAGS=$CFLAGS
CFLAGS="$pgac_save_CFLAGS -fno-aggressive-loop-optimizations"
cat >conftest.$ac_ext <<_ACEOF
/* confdefs.h. */
_ACEOF
cat confdefs.h >>conftest.$ac_ext
cat >>conftest.$ac_ext <<_ACEOF
/* end confdefs.h. */
int
main ()
{
;
return 0;
}
_ACEOF
rm -f conftest.$ac_objext
if { (ac_try="$ac_compile"
case "(($ac_try" in
*\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
*) ac_try_echo=$ac_try;;
esac
eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
$as_echo "$ac_try_echo") >&5
(eval "$ac_compile") 2>conftest.er1
ac_status=$?
grep -v '^ *+' conftest.er1 >conftest.err
rm -f conftest.er1
cat conftest.err >&5
$as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
(exit $ac_status); } && {
test -z "$ac_c_werror_flag" ||
test ! -s conftest.err
} && test -s conftest.$ac_objext; then
{ $as_echo "$as_me:$LINENO: result: yes" >&5
$as_echo "yes" >&6; }
else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
CFLAGS="$pgac_save_CFLAGS"
{ $as_echo "$as_me:$LINENO: result: no" >&5
$as_echo "no" >&6; }
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
elif test "$ICC" = yes; then