[Patch, fortran] PR27709 - Using size of array pointer component as dimension of function result causes gfortran internal error.

[Paul Thomas]

:ADDPATCH fortran:

This was http://gcc.gnu.org/ml/fortran/2006-05/msg00357.html and thread.

Well, in spite of living up to my name, I relented and was convinced 
that this is good code and that the bug should be fixed.  Thanks to 
Richard, Brooks and David Ham for a useful discussion.

Not only was I persuaded by this discussion but I was promptly hit by 
the same bug myself; so I had a double incentive to fix it.

The problem is clearly indicated in the attached testcase.  The internal 
error is triggered by multiple component references in an array bound 
specification expression.

It turned out that the routine that emits the error, 
resolve.c(find_array_spec), is also the cause of it.  As it is coded, it 
makes no attempt to go any deeper than one component reference and fails 
because it only checks the reference against any derived types that it 
finds in the primary derived type.  Thus, multiple component references 
in linked lists work; eg. real, dimension (size (self%next%next%data, 
1)) :: local is OK.

The fix is implemented by supplying a gfc_symbol that points to the 
derived type used in the last component reference.  The components of 
this derived type are used for comparison with the next component 
reference.  The testcase is that posted with the PR.

Regtested on FC5/Athlon1700.  OK for trunk and, when reopened, 4.1?

Paul

2006-05-21  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/27709
    * resolve.c (find_array_spec): Add gfc_symbol, derived, and
    use to track repeated component references.

2006-05-21  Paul Thomas  <pault@gcc.gnu.org>

    PR fortran/27709
    * gfortran.dg/spec_expr_4.f90: New test.


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