Re: [patch, libgfortran] Merge of fortran-dev IO to trunk

[Steve Ellcey <sje at cup dot hp dot com>]

On Mon, 2009-04-06 at 20:04 +0300, Janne Blomqvist wrote:

> Just out of curiosity, how does this situation arise? If you look at the 
> stack trace, it should be something like
> 
> convert_real
> read_f
> formatted_transfer_scalar_read
> formatted_transfer
> transfer_real
> 
> where the last is the library entry point. If you look at the code, 
> there is no pointer arithmetic or such done on *dest; The pointer that 
> we're writing via is provided as is by user space, so the frontend 
> should already have the place for the data in memory properly alYourigned.

I am not sure how we get unaligned, I am testing with
fortran.dg/arrayio_9.f90.  It seems to follow your stack trace.

! { dg-do run }
! PR29563 Internal read loses data.
! Test from test case. Submitted by Jerry DeLisle
<jvdelisle@gcc.gnu.org>
! Without patch, last value in array was being skipped in the read.
program pr29563
  character(len=10), dimension(3)::arraydata = (/' 1 2 3',' 4 5 6',' 7 8
9'/)
  real(kind=8), dimension(3,3) :: tmp
  tmp = 0.0
  read(arraydata,*,iostat=iostat)((tmp(i,j),j=1,3),i=1,3)
  if (tmp(3,3)-9.0.gt.0.0000001) call abort()
end program pr29563

The backtrace I see (using HP's gdb) is:
#0  0x9fffffffbd717700:0 in *_gfortrani_convert_real
(dtp=0x9fffffffffffef80, 
    dest=0x9ffffffffffff07c, buffer=0x6000000000021de0 "1", length=8)
    at /proj/opensrc/nightly/src/trunk/libgfortran/io/read.c:154
#1  0x9fffffffbd70c8d0:0 in read_real (length=8)
    at /proj/opensrc/nightly/src/trunk/libgfortran/io/list_read.c:1521
#2  0x9fffffffbd70ecd0:0 in list_formatted_read_scalar
(p=0x9ffffffffffff1a0, 
    kind=8, size=8)
    at /proj/opensrc/nightly/src/trunk/libgfortran/io/list_read.c:1765
#3  0x9fffffffbd70f780:0 in *_gfortrani_list_formatted_read (
    dtp=0x9fffffffffffef80, type=BT_REAL, size=8, nelems=1)
    at /proj/opensrc/nightly/src/trunk/libgfortran/io/list_read.c:1848
#4  0x9fffffffbd71a1b0:0 in *_gfortran_transfer_real
(dtp=0x9fffffffffffef80, 
    p=0x9ffffffffffff1a0, kind=8)
    at /proj/opensrc/nightly/src/trunk/libgfortran/io/transfer.c:1680