[llvm-commits] [llvm] r134231 - /llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp

[Jakob Stoklund Olesen]

On Jun 30, 2011, at 9:15 PM, Rafael Espindola wrote:

>   // FIXME: If "B = X" kills X, we have to move the kill back to its
>   // previous use. For now we just avoid the optimization in that case.

This is actually an easy FIXME. Se the other places that call li_->shrinkToUses() after remat etc.

The only trick is to call it after markAsJoined() has undef'ed all operands on the COPY instruction that is going away. Otherwise the undead COPY would still require liveness.

/jakob

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