[gmx-users] avx2 with gcc 4.8.3

[Harry Mark Greenblatt]

BS"D

Dear All,

  While trying to run cmake under Centos 6.6 on a Haswell cpu for Gromacs 5.0.3 using gcc 4.8.3, cmake fails claiming the compiler doesn't support AVX2, but as far as I know it should...

Cannot find AVX2 compiler flag.  Use a newer compiler, or choose AVX SIMD
  (slower).

Some tests for AVX2 *do* succeed:

-- Try C compiler AVX2 flag = [-mavx2]
-- Performing Test C_FLAG_mavx2
-- Performing Test C_FLAG_mavx2 - Success
...
-- Try C++ compiler AVX2 flag = [-mavx2]
-- Performing Test CXX_FLAG_mavx2
-- Performing Test CXX_FLAG_mavx2 - Success

Using  -DGMX_SIMD=AVX_256 does solve the problem, but then I lose AVX2 acceleration.

I am using CUDA 6.5-19 (which was compiled with gcc 4.4.7, but that doesn't seem to be the issue).

Any advice?

Thanks

Harry

Harry M. Greenblatt
Associate Staff Scientist
Dept of Structural Biology           harry.greenblatt at weizmann.ac.il<mailto:harry.greenblatt at weizmann.ac.il>
Weizmann Institute of Science        Phone:  972-8-934-3625
234 Herzl St.                        Facsimile:   972-8-934-4159
Rehovot, 76100
Israel