[llvm-commits] [llvm] r98023 - /llvm/trunk/lib/CodeGen/SimpleRegisterCoalescing.cpp

[Chris Lattner]

On Mar 9, 2010, at 10:15 AM, Jakob Stoklund Olesen wrote:

> 
> On Mar 9, 2010, at 9:41 AM, Jakob Stoklund Olesen wrote:
> 
>> 
>> On Mar 8, 2010, at 5:37 PM, Jakob Stoklund Olesen wrote:
>> 
>>> 
>>> On Mar 8, 2010, at 5:23 PM, Evan Cheng wrote:
>>> 
>>>> Is 1000 scientific? :-)
>>> 
>> 
>> The coalescer timing formed a perfect parabola with t=4.1s at N=2000. This is not a caching effect - the coalescer is quadratic in the number of function calls!
> 
> The attached graph shows the coalescer runtime as a function of the array length in my tiny test function (inlining disabled). The patch kicks in at N=500 and reduces runtime to nothing.

Is it possible to fix or improve the N^2 algorithm?

-Chris