[llvm-commits] [llvm] r126445 - in /llvm/trunk: lib/Transforms/Utils/SimplifyCFG.cpp test/Transforms/SimplifyCFG/select-gep.ll
Evan Cheng
evan.cheng at apple.com
Sat Feb 26 00:23:42 PST 2011
On Feb 25, 2011, at 9:48 AM, Benjamin Kramer wrote:
>
> On 25.02.2011, at 18:25, Evan Cheng wrote:
>
>>
>> On Feb 25, 2011, at 7:26 AM, Benjamin Kramer wrote:
>>
>>>
>>> On 25.02.2011, at 08:14, Evan Cheng wrote:
>>>
>>>> Speculation is nice, but I would feel a lot better if there are hard numbers to back this up. Are we sure these changes are improving performance?
>>>
>>> My unscientific test case (gcc compiled with clang -O3 parsing itself) showed a 0.25% speedup with the original patch (all-constant GEPs only, median of 5 runs, i386, penryn). I just retested with the change Frits suggested and it slowed down ~0.6% compared to the original run so I reverted it.
>>
>> Thanks. What tests are you using to evaluate this?
>
> I routinely use the nice C files from http://people.csail.mit.edu/smcc/projects/single-file-programs/
> which are easy to handle and large enough to get meaningful results for both compile time and run
> time. They're extracted from programs that are also part of SPEC CINT, so I'm confident the
> improvements will also show up there :)
These are nice, but not quite enough. In this future, please at least run the llvm testsuite for anything that might affect performance.
Thanks,
Evan
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