Force a loop to vectorize

Accelerated Computing HPC Compilers Legacy PGI Compilers
#1

I have a loop body with a lot of statements that is just refusing to vectorize, the output with -Minfo says that its not beneficial to vectorize. I want to see if this really the case, so I want to force the compiler to generate vector instructions. Is there a way to bypass the compiler cost model?

I have tried to add the following pragmas to the loop
#pragma loop ivdep
#pragma loop vector

I have also tried to add the following flags to the compilation "-fast -fastsse -Mvect=simd:256 -Mvect=nosizelimit ".

I am not posting the code here since the code is auto-generated and is too messy to read, and is not really relevant to my query.

#2

Hi Mahesh,

It appears that you tried all the usual ways to force vectorization. At this point we would need to see the code to better understand what’s going on. Can you send a reproducing example to PGI Customer Service (trs@pgroup.com)?

Thanks,
Mat