[llvm-commits] [llvm] r46959 - in /llvm/trunk: lib/Analysis/ScalarEvolution.cpp test/Analysis/ScalarEvolution/2008-02-11-ReversedCondition.ll

[Evan Cheng]

On Feb 24, 2008, at 1:55 PM, Wojciech Matyjewicz wrote:

> Hi,
>
>> I'm going to have to back out this patch temporarily.
>
> Okay.
>
>> This is causing
>> performance regression in an important benchmark. I don't think this
>> patch is really at fault. But I need time to investigate.
>
> Which benchmark is it? Probably, an expression for the iteration count

Something you can't see. :-)

>
> can be now created for a loop that wasn't previously analyzable. It  
> may
> be the case that -indvars currently introduces code to compute the
> iteration count before the loop, or to compute the exit value for some
> register in the loop after the loop. Sometimes this kind of code can  
> be
> really long...

Not sure at this point. I'll try to find out.

Evan

>
>
> Wojtek
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