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Re: Another case of DCE deleting live code



On Nov 9, 2004, at 6:36 PM, Diego Novillo wrote:




On Tue, 2004-11-09 at 18:09, Daniel Berlin wrote:



Yes. The tag_set we compute in get_tmt_for must be exactly what
get_alias_set returns. We use that to determine which pointers get the
same alias set and other checks.



Why isn't get_alias_set returning 0 for types with that flag set, which
would avoid anything but get_alias_set being modified?



Because that bit is set on TREE_TYPE (ptr) and what we are interested in
is TREE_TYPE (TREE_TYPE (ptr)) (ie, the type of the pointed-to memory
location).



Gah.
So TYPE_REF_CAN_ALIAS_ALL means that whatever it points to can alias anything?
That's ugly.




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