This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Fix a tcb crash and a potential bug on mainline




  This may be something Andrew may want to look into as part
of his immediate uses work??

It's something we've pondered and talked about a little. Basically with the immediate use work we would know where all the uses are and we could probably arrange to delete those uses.

How would you delete those uses? You don't know if those statements are dead, so you really can't do that.
If they are using the result of a deleted PHI or some other deleted
statement, then those statements must also be dead.  It's one of
the nice SSA properties.


Only if your pass performs *all* insertions and updates to statements before performing *any* removals of statements.
I believe some passes don't do this right now.
Otherwise, in the intermediate step, we would think some statements are dead when they are only dead because we haven't fixed them up yet :)
--Dan



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]