https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78187
Bug ID: 78187
Summary: -fno-automatic does not work with allocatable scalar
character result result
Product: gcc
Version: 6.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: nuclearlee at gmail dot com
Target Milestone: ---
Created attachment 39945
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39945&action=edit
test.f90 contains a module and a test program to demonstrate described bug.
Summary:
The attached code should returns an allocatable scalar character as a "result".
If I compile without -fno-automtic I get the correct result, if I compile with
-fno-automatic, I get an empty string that is allocated (for gfortran 6.2.0,
5.4.1, and 4.9.4. 4.8.5 gives close to the correct result with some garbage
appended to it). If I instead use the function name to return the result
(instead of using the keyword "result"), the function works with
-fno-automatic).
More details below.
Thanks,
Lee
Detail:
If I compile in Ubuntu using gcc-6.2 (gcc version 6.2.0 20160901 (Ubuntu
6.2.0-3ubuntu11~14.04) using the following command
$ gfortran-6 -o test.exe test.f90
I get the correct result:
$ ./test.exe
c|abcdef| T
If I compile using -fno-automatic, however, I get the folowing
$ gfortran-6 -fno-automatic -o test.exe test.f90
I get the correct result:
$ ./test.exe
c|| T
Also, If I change the function scalar in test_module so that I'm not using
"result", and instead declaring scalar and setting it, it returns the *correct*
result using -fno-automatic, i.e.,
function scalar(a, b) result(c)
character(len=*), intent(in) :: a, b
character(len=:), allocatable :: scalar
scalar = trim(a)//trim(b)
end function scalar
I used a few different versions and -fno-automatic has the same result in all
of them (4.9.4, 5.4.1 and 4.8.5). gfortran 4.8.5 returns the closest to a
correct result (though still incorrect):
$ gfortran-4.8 -fno-automatic -o test.exe test.f90
$ ./test.exe
c|abcdef�q�abcdef��| T
