On Thu, 23 Mar 2017, Jakub Jelinek wrote:
> > + if (vf != 1)
> > + continue;
> > + unlink_stmt_vdef (stmt);
>
> This is weird. AFAIK unlink_stmt_vdef just replaces the uses of the vdef
> of that stmt with the vuse, but it still keeps the vdef (and vuse) around
> on the stmt, typically it is used when you are removing that stmt, but
> that is not the case here. So why are you doing it and not say removing the
> vdef?
Maybe I misunderstand your question, but actually the statement is removed
further below, when we break out of the switch:
stmt = lhs ? gimple_build_assign (lhs, rhs) : gimple_build_nop ();
gsi_replace (&gsi, stmt, false);
The same tactic is already in place for cleaning up GOMP_SIMT_ORDERED_PRED.
Thus, there's just one place that actually replaces statements; the body of
the switch is only responsible for coming up with a suitable rhs and cleaning
up vdefs for those statements where we know they would be present.
Thanks.
Alexander
