On Thu, Nov 24, 2011 at 5:28 PM, Michael Matz <m...@suse.de> wrote:
> Hi,
>
> On Thu, 24 Nov 2011, Jakub Jelinek wrote:
>
>> When stmt is mem = {v} {CLOBBER};, then lhs is neither
>> SSA_NAME, but it doesn't satisfy gimple_assign_copy_p either.
>> With this patch it will set the new_tree also to the clobber,
>> making it clear that the next iteration uses unitialized variable.
>
> Hmm. My guts don't like clobbers on the RHS of normal ssa operations.
> Usually our uninitialized values are the default defs of SSA names that
> aren't PARM_DECLs. I don't like having two ways of expressing
> uninitializedness.
>
> As the default defs are already automatically handled by all our ssa
> infrastructure (including warning and propagation machinery) I think it
> would be best to generate such one instead of a clobber for the RHS.
I think the patch is ok. Does the CLOBBER get re-placed anywhere?
Richard.
>
> Ciao,
> Michael.
