https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70235
--- Comment #16 from Dominique d'Humieres <dominiq at lps dot ens.fr> --- > Created attachment 38090 [details] > Updated patch correcting problem found by Dominique With this updated patch and y = 643.125 and d=2, I get -8pf18.2 y= 1.00 -7pf18.2 y= 1.00 -6pf18.2 y= 1.00 -5pf18.2 y= 1.00 -4pf18.2 y= 0.06 -3pf18.2 y= 0.64 -2pf18.2 y= 6.43 -1pf18.2 y= 64.31 0pf18.2 y= 643.12 1pf18.2 y= 6431.25 2pf18.2 y= 64312.50 3pf18.2 y= 643125.00 4pf18.2 y= 6431250.00 5pf18.2 y= 64312500.00 6pf18.2 y= 643125000.00 7pf18.2 y= 6431250000.00 while I get -8pf18.2 y= 0.00 -7pf18.2 y= 0.00 -6pf18.2 y= 0.00 -5pf18.2 y= 0.00 -4pf18.2 y= 0.06 -3pf18.2 y= 0.64 -2pf18.2 y= 6.43 -1pf18.2 y= 64.31 0pf18.2 y= 643.12 1pf18.2 y= 6431.25 2pf18.2 y= 64312.50 3pf18.2 y= 643125.00 4pf18.2 y= 6431250.00 5pf18.2 y= 64312500.00 6pf18.2 y= 643125000.00 7pf18.2 y= 6431250000.00 Note that -5pf18.2 y= should be 0.01 if correctly rounded. The rounding error comes from the addition of + precision += dtp->u.p.scale_factor; + if (precision < f->u.real.d) + precision = f->u.real.d; in my patch.
