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Re: [gfortran,patch] PR 15809, part 1

On Thursday 01 September 2005 13:56, Erik Edelmann wrote:
> wrote:
> > :ADDPATCH <fortran>:
> >
> > The attached patch fixes one of the two bugs in 15809.
> >
> > The cause of the bug is that in trans-array.c/gfc_trans_deferred_array()
> > we require that TREE_CODE (sym->backend_decl) == VAR_DECL.
> > For dummy variables, however, TREE_CODE (sym->backend_decl) is
> > PARM_DECL.  We need to accept that as well.
> >
> > Bubblestrapped & reg. tested on 4.0 and mainline (Linux/x86).
> > Please commit if OK.
> Don't commit yet.  While I still think the patch is correct in
> the sense that it fixes the bug and doesn't break anything, I
> also think that there might be a better way to fix the bug.
> The reasons why I think this:
> 1) gfc_trans_deferred_array() doesn't do anything special for
> dummy arguments.
> 2) gfc_trans_deferred_array() seems to not be called for any
> other type of dummies than
> CHARACTER(len=<expression_involving_other_dummy_var>).

It's only called for variables that have a non-constant length.
For constant length variables we already know the length so don't have to do 
anything. For non-constant length we need to evaluate the string length 

Deferred shape arguments are a special case because the standard requires that 
the actual length be the same as the dummy length, so evaluating the len= 
expression is optional (we could use the passed length directly). It'd be 
nice if we could add checking code to enforce this when -fbounds-check.

> The better solution I'm thinking of is to just avoid calling
> gfc_trans_deferred_array() for (any kind of) dummy arguments.

Possibly. This may end up being more hassle than just ignoring the ones where 
we don't have to do anything.


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