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Re: Eliminate write-only variables


> 
> Yeah, I discussed this with martin today on irc.  For aliasing we'd like to know whether a decl possibly has its address taken. Currently we only trust TREE_ADDRESSABLE for statics - and lto might change those to hidden visibility public :(
> 
> So we want deck_referred_to_by_single_function 

OK, I will implement this one in IPA mini-pass.  It is easy.
This property changes by clonning and inlining. What Martin wants to use it for?
(I.e. my plan would be to compute it as last IPA pass making it useless for
IPA analysis&propagation)

> and deck_may_have_address_taken.

We currently clear TREE_ADDRESSABLE for statics that have no address taken at
WPA time and that ought to keep the flag cleared at ltrans (I think I even made
testcase for this)

What I think we could improve is to not consider string functions as ADDR operations
for this analysis, i.e. it is common to only memset to 0.

How may_have_address_taken would differ here?

Honza


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