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Re: [tcb]: Add RHS to V_MUST_DEF
On Mon, 2004-10-04 at 15:13 -0400, Andrew MacLeod wrote:
>
> Yeah, we discussed it a bit, and I think exposing the RHS in the MUST
> defs is the right thing.
>
> All we need to avoid the renaming in DCE is to figure out which argument
> of the PHI is to be propagated. Dan thinks he can figure that out, then
> its simply a matter of propagating the value and we have no more
> renaming.
>
> SO I think where we currently stand is:
>
> - expose the RHS of the V_MUST_DEF as a KILL.
> - This kill will also be a reference which shows up in the
> immeidate_uses info since it is now a reference in an operand.
> - DCE will use immediate_uses to do this, as it will be free in 4.1
Right.
>
> Dan has issues with partial renaming (wants multiple RHS arguments to a
> MUST DEF), but we'll visit that later :-)
Right.
It may turn out there is a better way to do that (have real vkill
operands, some other idea we've all missed). It's unknown at this point.
I only even mentioned it to Andrew so that he was aware of possible
future problems :)
>
>
> Andrew
>
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