https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71363
--- Comment #3 from Paul Mustiere <paul.mustiere at gmail dot com> --- In the script: possible_real_kinds="4 8 10 16" i.e. it tries them all In the for loop, when it tries to compile the dummy Fortran program to check each kind=k existance, only 4, 8 & 16 exists. kind=4 is defined as float, kind=8 is defined as double, kind=16 is defined as long double. The issue being that long double = double in this case. When kind=16 match in C is defined, there's the check: 16) if [ $long_double_kind -eq 10 ]; then Could it be that kind=16 should be match to __float128, and the check should be $long_double_kind -neq 16?