------- Comment #8 from tkoenig at gcc dot gnu dot org 2009-08-12 20:36 -------
(In reply to comment #7)
> An interesting approach. As long as you don't print array slices in the
> loops this should work around the escaping pointer problem. It comes at
> the risk of creating excessive copies.
Apparently, the optimizers are smart enough for that at least for
simple cases.
The loop in the following subroutine gets translated to
subroutine foo
do i=1,10
call bar((i))
end do
end subroutine foo
leal -12(%ebp), %esi
.p2align 4,,7
L2:
movl %ebx, -12(%ebp)
addl $1, %ebx
movl %esi, (%esp)
call bar_
cmpl $11, %ebx
jne L2
which is pretty good.
> Actually, perhaps the right way of achieving this is not to add
> OP_PARENTHESES in the frontend, but to do a copy when creating the call.
This would likely have the same result, the subprogram
subroutine foo
do i=1,10
j = i
call bar(j)
end do
end subroutine foo
gets the same code as the one above.
For comparision, the unadorned
$ cat a.f90
subroutine foo
do i=1,10
call bar(i)
end do
end subroutine foo
gets
movl $1, -12(%ebp)
.L2:
movl %ebx, (%esp)
call bar_
movl -12(%ebp), %eax
leal 1(%eax), %edx
cmpl $10, %eax
movl %edx, -12(%ebp)
jne .L2
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31593
