[RFC] Clean up SSE variable shifts

[Richard Henderson]

On 08/21/2010 03:27 PM, Lu, Hongjiu wrote:
>>
>>> What is the performance impact of extra function call
>>> vs. multiple copies of the same jump table?
>>
>> I don't know.  I would hope that an indirect call and return
>> would be just as predictable as an indirect jump and branch.
>>
>> Fancy helping me benchmark?
>>
> 
> Sure. Send me a patch. I will run some benchmarks.

And for good measure, here's a third patch which implements a
variable shift via pshufb.  Which means we avoid any control
mis-prediction in favor of a data load stall.  Whether this is 
better or worse given a large insn re-order buffer, I have
no idea.  Something else to test.


r~
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