https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107815
--- Comment #18 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Or better yet #include <stdlib.h> #include <stdio.h> int main () { char *end; const char *p = "6e-4966"; long double l = strtold (p, &end); if (l != __LDBL_DENORM_MIN__ || end != p + 7) printf ("%Le %s\n", l, end); p = "1e-4965"; l = strtold (p, &end); if (l != 2.0L * __LDBL_DENORM_MIN__ || end != p + 7) printf ("%Le %s\n", l, end); p = "2e-4965"; l = strtold (p, &end); if (l != 3.0L * __LDBL_DENORM_MIN__ || end != p + 7) printf ("%Le %s\n", l, end); return 0; } so that we know if it is just the denorm_min() case or also other denormals.