$ cat write-many.f
program main
open(10,status='SCRATCH')
a = 0.3858204
do i=1,1000000
a = a + 0.4761748164
write(10, '(G12.5)'),a
end do
end
$ gfortran write-many.f
$ time ./a.out
real 0m8.165s
user 0m8.092s
sys 0m0.059s
$ g77 write-many.f
$ time ./a.out
real 0m5.760s
user 0m5.719s
sys 0m0.032s
$ gfortran -v
Using built-in specs.
Target: ia64-unknown-linux-gnu
Configured with: ../gcc-4.1-20050227/configure --prefix=/home/zfkts
--enable-languages=c,f95
Thread model: posix
gcc version 4.1.0 20050227 (experimental)
--
Summary: Performance regression in formatted output vs. g77
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: libfortran
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: Thomas dot Koenig at online dot de
CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: ia64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20278
