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Bug #2150

fftw SIMD compile flags vanished with 2016.3

Added by Johannes Wagner over 3 years ago. Updated over 3 years ago.

Status:
Closed
Priority:
High
Assignee:
-
Category:
build system
Target version:
Affected version - extra info:
Affected version:
Difficulty:
simple
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Description

Since the last point release 2016.3, cmake .. -DGMX_BUILD_OWN_FFTW=ON does not issue any SIMD compile flags to cmake anymore. Probably related to:

https://github.com/gromacs/gromacs/commit/aa905d647e272792f67d93994578d0bb0eeb0f3f

tested with gcc 6.3.1 on arch and fedora 25.

To reproduce, just run cmake .. -DGMX_BUILD_OWN_FFTW=ON and check fftw compile flags

History

#1 Updated by Vedran Miletic over 3 years ago

Johannes Wagner wrote:

Since the last point release 2016.3, cmake .. -DGMX_BUILD_OWN_FFTW=ON does not issue any SIMD compile flags to cmake anymore. Probably related to:

https://github.com/gromacs/gromacs/commit/aa905d647e272792f67d93994578d0bb0eeb0f3f

tested with gcc 6.3.1 on arch and fedora 25.

To reproduce, just run cmake .. -DGMX_BUILD_OWN_FFTW=ON and check fftw compile flags

Probably fixed by: https://gerrit.gromacs.org/#/c/6569/

#2 Updated by Mark Abraham over 3 years ago

  • Status changed from New to Closed

#3 Updated by Johannes Wagner over 3 years ago

Has to be opened again. On linux it is fixed as far as I can tell (Fedora25), but compiling on macOS 10.12.4 with homebrew installed GCC 6.3.0_1 --without-multilib; cmake still gives on an Ivy Bridge macbook (AVX1):

-- The GROMACS-managed build of FFTW 3 will configure with the following optimizations: --enable-sse2
-- Using external FFT library - FFTW3 build managed by GROMACS

compiled with:

export CC=/usr/local/bin/gcc-6
export CXX=/usr/local/bin/g++-6
git clone https://github.com/gromacs/gromacs.git --branch release-2016 --single-branch gromacs-2016-git

cmake .. -DGMX_BUILD_OWN_FFTW=ON -DCMAKE_INSTALL_PREFIX=~/programs/gromacs/2016-git

#4 Updated by Mark Abraham over 3 years ago

Yes, that's deliberate: https://redmine.gromacs.org/projects/gromacs/repository/revisions/master/entry/src/contrib/fftw/CMakeLists.txt#L63

I can reproduce your issue with gcc 6.3 in macports on my Haswell 2011 Macbook, but if I hack it to permit it to configure with avx support, the assembler does not compile the AVX instructions from the FFTW source. If you can get a standalone FFTW to build with that toolchain, then perhaps we can figure how to get something done.

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