https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93567
--- Comment #3 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
With
--- ../_clean/libgfortran/io/write_float.def 2020-06-13 03:11:55.000000000
+0200
+++ libgfortran/io/write_float.def 2020-07-20 18:17:41.000000000 +0200
@@ -990,7 +990,7 @@ determine_en_precision (st_parameter_dt
switch (dtp->u.p.current_unit->round_status)\
{\
case ROUND_ZERO:\
- r = sign_bit ? 1.0 : 0.0;\
+ r = sign_bit ? -1.0 : 0.0;\
break;\
case ROUND_UP:\
r = 1.0;\
@@ -1004,7 +1004,7 @@ determine_en_precision (st_parameter_dt
exp_d = calculate_exp_ ## x (d);\
r_sc = (1 - r / exp_d);\
temp = 0.1 * r_sc;\
- if ((m > 0.0 && ((m < temp) || (r >= (exp_d - m))))\
+ if ((m > 0.0 && ((m < temp) || (r > (exp_d - m - sign_bit))))\
|| ((m == 0.0) && !(compile_options.allow_std\
& (GFC_STD_F2003 | GFC_STD_F2008)))\
|| d == 0)\
the extended test case
program test_rug
print "(G12.2, a)", 99.0_8, " expected 99."
print "(G12.2, a)", 100.0_8, " expected 0.10E+03"
print "(RU,G12.2, a)", 99.0_8, " expected 99."
print "(RU,G12.2, a)", 99.01_8, " expected 0.10E+03"
print "(RU,G12.4,a)", 99.0_8 , " expected 99.00"
print "(RU,G12.4,a)", 99.01_8, " expected 99.02"
print "(RD,G12.2,a)", 99.0_8, " expected 99."
print "(RD,G12.2,a)", 99.01_8, " expected 99."
print "(RD,G12.2,a)", -99.0_8, " expected -99."
print "(RD,G12.2,a)", -99.01_8, " expected -0.10E+03"
print "(RD,G12.2,a)", -100.00_8, " expected -0.10E+03"
print "(Rz,G12.2,a)", -99.01_8, " expected -99."
print "(Rz,G12.2,a)", -100.01_8, " expected -0.10E+03"
end
gives the expected results.
Note that this "fix" is empirical and I am not 100% convinced it will work for
all cases.
