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From: Jan Hubicka <hubicka@kam.mff.cuni.cz>
To: Richard Biener <richard.guenther@gmail.com>
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Subject: Re: Use modref summary to DSE calls to non-pure functions
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> > Hmm, I could try to do this, but possibly incrementally?
> 
> You mean handle a &decl argument specially for unknown param offset?
> Yeah, I guess so.

I think it is also pointer that was allocated and is going to be
freed...
> 
> > Basically I want to have
> >
> > foo (&decl)
> > decl = {}
> >
> > To be matched since even if I do not know the offset I know it is dead
> > after end of lifetime of the decl.  I am not quite sure PTA will give me
> > that?
> 
> for this case PTA should tell you the alias is to 'decl' only but then I'm
> not sure if stmt_kills_ref_p is up to the task to determine that 'decl = {}',
> from a quick look it doesn't.  So indeed the only interesting case will
> be a &decl based parameter which we can special-case.

Yep, i do not think it understands this.  I will look into it - I guess
it is common enough to care about.

Honza