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SIMD : VEXT -32-q1-q1-q1-3-slow

Hi, i have some issue on an inplace vetx.32 instructions. I post it on the Cortex A forum. Who has a tip or workaround as it is too slow on A7,A8,A9, etc... ? thanks

vetx-32-q1-q1-q1-3-slow

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Tamar Christina over 5 years ago +1

Hi br-dev, If you're talking about the latency of the instruction itself then there isn't really an alternative to it, You could in principle do it with two shifts (left and right) and an or, but that...

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0 Paul Black over 5 years ago

Hi,

Which compiler are you using?

Thanks,

Paul.
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0 Paul Black over 5 years ago

Hi,

Which compiler are you using?

Thanks,

Paul.
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0 br-dev over 5 years ago in reply to Paul Black

Hi Paul, gcc 8.3 but i did bench on many ARM (a7,a8,a9,a53,a72) and the results is homogeneous (different also) but seems logical. How ever i am not that much happy to spend so much cycles (5 on A7) for a single line instruction. I am happy if you can ask the team some workaround. cheers. bruno
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0 Peterson Quadros over 5 years ago in reply to br-dev

Hi,

This is the Arm Compiler forum. Your query would be better answered in the GCC toolchain forum: https://community.arm.com/developer/tools-software/oss-platforms/f/gnu-toolchain-forum

Thanks

Peterson
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