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Re: Speedup CSE by 5%
- From: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- To: bernds_cb1 at t-online dot de
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Thu, 27 Jan 05 10:12:19 EST
- Subject: Re: Speedup CSE by 5%
Kenner, any idea what it was for?
I take back part of my last message: the sharing concern clearly had
nothing to do with that validate_change. And I'm sure it was also
addressing the case where fold_rtx would return its input unchanged.
But I'm not sure exactly what the sharing was. I'm fairly sure that
the copy_rtx wouldn't have been put there had there not been some bug,
but it's anybody's guess as to whether that is still an issue nine
years later. One possibility is that it's not sharing at all, but a concern
that something is in the wrong obstack. If that's so, then it's not a current
issue at all.