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GCC 12 warns too much about <regex>

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See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105562

* m4/gccwarn.m4: Compile a small regex and add
-Wno-maybe-uninitialized if needed.
This commit is contained in:
Alexandre Duret-Lutz 2022-05-17 16:59:01 +02:00
parent 10bc253dd8
commit 99d030f5e1
1 changed files with 31 additions and 8 deletions
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39
m4/gccwarn.m4
View file

@ -21,6 +21,7 @@ AC_DEFUN([CF_GXX_WARNINGS],
cat > conftest.$ac_ext <<EOF
#line __oline__ "configure"
#include <string>
#include <regex>
int main(int argc, char *argv[[]])
{
// This string comparison is here to detect superfluous
@ -33,19 +34,26 @@ int main(int argc, char *argv[[]])
std::string a{"foo"}, b{"bar"};
if (b < a)
return 1;
// GCC 12 has spurious warnings about ininialized values in regex.
// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105562
// We need -Wno-maybe-uninitialized in this case.
std::regex r{"a"};
(void)r;
return argv[[argc-1]] == nullptr;
}
EOF
cf_save_CXXFLAGS="$CXXFLAGS"
ac_cv_prog_gxx_warn_flags="-W -Wall"
ac_cv_prog_gxx_warn_flags="-W -Werror"
dnl The following list has options of the form OPT:BAD:GOOD
dnl if -OPT fails we try -OPT -BAD. If -OPT succeeds we add -GOOD.
for cf_opt in \
Werror \
Wall:Wno-maybe-uninitialized:\
Wint-to-void-pointer-cast \
Wzero-as-null-pointer-constant \
Wcast-align \
Wpointer-arith \
Wwrite-strings \
Wcast-qual \
Wcast-qual::DXTSTRINGDEFINES \
Wdocumentation \
Wmissing-declarations \
Wnoexcept \
@ -58,11 +66,26 @@ EOF
Wsuggest-override \
Wpedantic
do
CXXFLAGS="$cf_save_CXXFLAGS $ac_cv_prog_gxx_warn_flags -$cf_opt"
if AC_TRY_EVAL(ac_compile); then
ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -$cf_opt"
test "$cf_opt" = Wcast-qual && ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -DXTSTRINGDEFINES"
fi
fopt=${cf_opt%%:*}
CXXFLAGS="$cf_save_CXXFLAGS $ac_cv_prog_gxx_warn_flags -$fopt"
if AC_TRY_EVAL(ac_compile); then
ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -$fopt"
case $cf_opt in
*:*:);;
*:*:*)ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -${cf_opt##*:}";;
esac
else
case $cf_opt in
*::*);;
*:*:*)
sopt=${cf_opt%:*}
sopt=${sopt#*:}
CXXFLAGS="$cf_save_CXXFLAGS $ac_cv_prog_gxx_warn_flags -$fopt -$sopt"
if AC_TRY_EVAL(ac_compile); then
ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -$fopt -$sopt"
fi;;
esac
fi
done
rm -f conftest*
CXXFLAGS="$cf_save_CXXFLAGS"])