[PATCH] IndVarSimplify : do not recompute an IV value used outside of the loop if it is trivially known not to be beneficial

[Arnaud A. de Grandmaison]

Ping ?

On 03/14/2013 11:08 PM, Arnaud de Grandmaison wrote:
> On Tuesday 05 March 2013 10:14:37 Andrew Trick wrote:
>> On Mar 5, 2013, at 7:30 AM, "Arnaud A. de Grandmaison" 
> <arnaud.adegm at gmail.com> wrote:
>>>> I would at least gather optimization stats across llvm test-suite before
>>>> supressing exit value replacement to make sure we're not preventing
>>>> other optimization.> 
>>> I have never done that before, but that's a good time to start :)
>> There should be a way to gather stats with lnt, but I don't know how.
>> Unfortunately, I still use the TEST=nightly like this:
>>
>> make build -j8 TEST=nightly \
>> TARGET_FLAGS="-arch x86_64 -Wno-error=implicit-function-declaration" \
>> OPTFLAGS=-O3 ARCH=x86_64 CC_UNDER_TEST_TARGET_IS_X86_64=1 \
>> ENABLE_BUILT_CLANG=1 LLVMCC_OPTION=clang CC_UNDER_TEST_IS_CLANG=1
>>
>> And the attached python script to compare runs.
>>
>> -Andy
> Hi Andy
>
> Thanks for the pointers and apologize for the delay. It took me some time to 
> be able to use the lnt, I believe this time is worth the investment.
>
> The attached patch addresses the different points we have discussed. I have 
> also added another testcase. I have not noticed any performance regression 
> with lnt as this optimization is not triggered --- with lnt's stock testcases. 
> On the other hand, the optimization triggers on real code on my targets.
>
> Cheers,
> --
> Arnaud de Grandmaison


-- 
Arnaud A. de Grandmaison