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Re: CSE not combining equivalent expressions.


On Thu, 2007-01-18 at 09:41 +0100, Steven Bosscher wrote:

> There appear to be more bit operations in RTL, so perhaps it is a
> better idea to implement a known-bits propagation pass for RTL, with
> the new dataflow engine.
If that's the case then most of the opportunities are appearing due to
lowering of the IL which would make a lot of sense for detecting
useless sign/zero extensions.

I'm not immediately aware of too many cases where lowering the IL is
going to expose new opportunities to track and optimize nonzero/zero
bits stuff.  

Jeff


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