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Re: [tree-ssa] Lazy updating of stmt operands
On Sunday 07 December 2003 18:29, Diego Novillo wrote:
> > > tree-dfa.c:compute_immediate_uses()
> >
> > Which needs to pass through every single statement in the program. Not
> > really terribly efficient.
>
> *shrug*, it's used by SSA-CCP. Since def-use edges are only needed by
> some passes, I don't think it would be worth our while trying to
> maintain them in get_stmt_operands.
There are going to be more passes that need immediate uses. Even a simple
pass to kill redundant PHIs (say, after unswitching a loop) will have to go
over _all_ statements to get the immediate uses of one or two statements. It
would be really nice if there were some way to keep this information
up-to-date at all times...
Gr.
Steven