Re: [PR debug/41343] introduce debug expr temps

[Alexandre Oliva <aoliva@redhat.com>]

On Oct  6, 2009, Richard Guenther <richard.guenther@gmail.com> wrote:

>> Anyhow, if we find it not to be true, it shouldn't be too hard to get
>> debug temps into SSA operands, especially if we're to add vops to debug
>> bind stmts as well.

> Gah.  Over my dead body!

:-)

> Fair enough.  Mind adding a comment here?  Mind adding
> a DEBUG_DECL_UID macro that encapsulates the negation?

Will do.

>> But the bind point is that where the stmt was before, and the moved DEF
>> might very well be referenced at a point between the bind point and the
>> reinsertion point.

> Please get some numbers here - I think this will for example
> artificially add debug stmts on basic block removal.

We remove basic blocks “backwards” too, from last to first stmt, and
dominated before dominator.  So, since the newly-added code only adds a
debug stmt if it finds the removed SSA DEF is USEd in a debug stmt, it
would only add a deug stmt if we were to remove a dominator without
removing its dominated, i.e., if we were to remove an SSA DEF without
removing its corresponding USEs.  We don't do that, do we?

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer