------- Comment #5 from burnus at gcc dot gnu dot org 2010-02-25 13:54 -------
type :: thytype
integer(4), allocatable :: h(:)
end type thytype
type :: mytype
type(thytype), allocatable :: q(:)
end type mytype
type (mytype) :: x
x = mytype ([thytype([555])])
end
Reduced test case. If I read the dump correctly, one effectively does:
tmp = thytype([555])
x = mytype(tmp)
however, for "mytype(tmp)" the data is copied instead of simply assigning the
pointer "tmp.data" and "tmp.data" is never freed.
a) One creates "thytype" with the value 555:
(*(struct thytype[1] * restrict) atmp.1.data)[0] = thytype.4;
- and recopying again:
(*(struct thytype[1] * restrict) atmp.7.data)[S.9] = (*(struct thytype[1] *
restrict) atmp.1.data)[S.9];
b) One now assigns that data to "mytype" - but not directly but via
malloc+memcopy:
D.1592 = (void * restrict) __builtin_malloc (MAX_EXPR <D.1591, 1>);
(*(struct thytype[0:] * restrict) mytype.0.q.data)[S.10].h.data = D.1592;
__builtin_memcpy ((integer(kind=4)[0:] * restrict) (*(struct thytype[0:] *
restrict) mytype.0.q.data)[S.10].h.data, (integer(kind=4)[0:] * restrict)
(*(struct thytype[1] * restrict) atmp.7.data)[S.10].h.data, D.1590 * 4);
The problem is now that "atmp.7.data.h.data" is never freed.
It would be fantastic if instead of freeing atmp.7.data.h.data one could simply
assign atmp.7.data.h.data to mytype.0.q.data[S.10].h.data without
malloc/memcpy. I am sure it is nontrivial, but I would really like to see the
number of temporaries be cut down. The dumps are pretty hard to read and we
probably give also the middle end a hard time in figuring out that we do not
need ~8 mallocs but one three - especially since the middle end does not really
optimize malloc/free (it could, but it doesn't - yet).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38319
