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Re: Speedup CSE by 5%


Hi Bernd,

> There are two possible reasons for the copy_rtx I can think of: either 
> fold_rtx destructively modifies its input (which I shouldn't happen from 
> what I can see), or we have RTL sharing issues.  In the latter case, we 
> can postpone the copy until after we found that fold_rtx has made a change.

But if X points to a part of INSN, we may be indirectly modifying X
through modifications to INSN.

Kazu Hirata


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