https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64927
Bug ID: 64927
Summary: [4.7/4.8 Regression] Surprising error with
-Wsurprising (-Wall) and TRANSFER + C_ASSOCIATED
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: anlauf at gmx dot de
The following error occurs with 4.7 and 4.8, but not with 4.6 or 4.9.
The error is slightly annoying since -Wsurprising is automatically
enabled by -Wall, and it was a try-and-error by a colleague to trace
the problem to -Wsurprising.
The error shows up only if both indicated code lines with TRANSFER
and C_ASSOCIATED are active, commenting out any of them makes the
error disappear. The dump-tree for 4.8 and 4.9 does not show
any difference if -Wno-surprising is set. The error is bogus.
> cat gfcbug130.f90
! gfortran -c gfcbug130.f90 -Wall
! false error, compare -Wsurprising vs. -Wno-surprising
module surprise
use iso_c_binding
implicit none
TYPE t_pointer
TYPE(c_ptr) :: cptr
END TYPE t_pointer
contains
SUBROUTINE get_pointer (ibuf)
INTEGER, INTENT(IN) :: ibuf(:)
TYPE(t_pointer) :: zp
! Error disappears if any line is commented out:
zp = TRANSFER (ibuf, zp)
IF (C_ASSOCIATED (zp% cptr)) Print *, "OK"
END SUBROUTINE get_pointer
end module surprise
> gfc-48 -c gfcbug130.f90 -Wall
gfcbug130.f90:16.22:
IF (C_ASSOCIATED (zp% cptr)) Print *, "OK"
1
Error: Type mismatch in argument 'c_ptr_1' at (1); passed INTEGER(4) to
TYPE(c_ptr)
> gfc-48 -c gfcbug130.f90 -Wall -Wno-surprising
The problem does not occur in 4.9. If there is an
easy fix for 4.8, could it be backported?
(I understand that the 4.7 branch is already closed.)
Thanks,
Harald
