[cfe-dev] Performance problem with SIMD support

[Richard Hadsell]

On 09/06/2013 05:16 PM, Richard Hadsell wrote:
> I'll see what I can do about a simpler test case.
>
> I just talked with a colleague more familiar with our SIMD code, and he pointed out that our function called in this test case is using asm code for the SIMD instructions, not the intrinsic functions.  My guess that the difference was due to _mm_ 
> functions was wrong.  I apologize for jumping to the wrong conclusion.
>
> This colleague thinks the problem might be related to data packing, which compilers could handle differently.  I will try to send our code in a case that demonstrates the performance issue.

Another colleague pointed out that we are compiling the functions using asm code with '-fno-dse' for G++ builds.  Perhaps this option will help for Clang++, too.

I will try it out as soon as I can re-enable our SIMD code and rebuild everything.

-- 
Dick Hadsell			203-992-6320  Fax: 203-992-6001
Reply-to:			hadsell at blueskystudios.com
Blue Sky Studios                http://www.blueskystudios.com
1 American Lane, Greenwich, CT 06831-2560