https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91734

Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- This is: /* sqrt(x) < c is the same as x < c*c, if we ignore NaNs. */ (if (! HONOR_NANS (@0)) (cmp @0 { build_real (TREE_TYPE (@0), c2); }) /* sqrt(x) < c is the same as x >= 0 && x < c*c. */ (if (GENERIC) (truth_andif (ge @0 { build_real (TREE_TYPE (@0), dconst0); }) (cmp @0 { build_real (TREE_TYPE (@0), c2); }))))))))) c here is 1.17549435082228750796873653722224567781866555677208752151e-38f, so c2 is 0.0f because the product is smaller than smallest positive subnormal float. Obviously, in that case we can't use < c2, but need to use <= c2. Maybe we probably should compute c2 with rounding towards positive infinity, then we could keep using < c2.