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Re: Speedup CSE by 5%


Kazu Hirata wrote:
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.

I don't follow, sorry. In the context we're talking about, INSN is NULL_RTX in fold_rtx.



Bernd



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