[Bug debug/23551] dwarf records for inlines appear incomplete

["drow at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #10 from drow at gcc dot gnu dot org  2006-07-21 16:57 -------
(In reply to comment #9)
> Case 1:
> There is no location info for the parameter x because it has been optimized
> away.  Change the variable x in main to y to avoid ambiguity, compile with
> -fdump-tree-all, and look at the t27 and t29 dumps.  In the t27 dump, the
> variable x is there and assigned to.  In the t29 dump, the variable x is there,
> but no longer assigned to.  Since it is no longer assigned to, we never
> allocate space for it, and hence no location attribute can be emitted.  t29 is
> the copyrename dump file.  If I compile with -fno-tree-copyrename, then I do
> get a location attribute for the parameter x in the inlined copy of foo.  I
> don't think there is any bug here, but if there is, it would be in the tree
> copyrename pass, because there is no longer any useful parameter x when it is
> done.

For the record, I encountered this problem today also (formals with no location
information).  Not a single argument had a location.  Adding
-fno-tree-copyrename fixed one (of about seven).  In this case the variables
are all used, mostly in non-trivial ways.  My testcase was eval.c from GDB; the
function evaluate_struct_tuple is inlined and debugging into it is quite hard. 
I'm working on improving this in GDB, but I can't improve where the compiler
gives me nothing to work with.

We already know that there are many similar problems in the tree optimizers;
I'm just adding a data point.


-- 

drow at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-07-21 16:57:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23551