https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91030
--- Comment #6 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- I cannot reproduce this on an AMD Ryzen 7 1700X (little-endian): $ gfortran -fconvert=native wr.f90 walltime.c cc1: Warnung: command-line option »-fconvert=native« is valid for Fortran but not for C $ rm -f out.dat ; time ./a.out ; rm -f out.dat write time(sec) = 1.0676949024200439 done real 0m1.399s user 0m0.112s sys 0m1.083s $ gfortran -fconvert=big-endian wr.f90 walltime.c cc1: Warnung: command-line option »-fconvert=big-endian« is valid for Fortran but not for C $ rm -f out.dat ; time ./a.out ; rm -f out.dat write time(sec) = 1.4781639575958252 done real 0m1.773s user 0m0.397s sys 0m1.196s which looks reasonable. Platform specific? Which OS/processor combination did you test this on?
