[LLVMdev] Instruction combiner: converting arithmetic into bit operations

[Krzysztof Parzyszek]

On 10/17/2012 11:57 AM, Chris Lattner wrote:
>
> We do want one canonical form, but it would be an interesting experiment to see what happens when we turned 'or' into 'add' instead of the other way around.  We'd have to make sure that simplifydemandedbits and friend can handle the add case as well as the or case, but I think it is already close to smart enough to do that.

I looked in Reassociate.cpp and I saw that it internally converts shifts 
into multiplications.  I think it would be worthwhile to at least 
investigate this possibility further.

-K

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