topic OpenMP and !DEC$ attributes in Intel® Fortran Compiler

OpenMP and !DEC$ attributes

Pellegrini__Etienne — Tue, 14 Oct 2014 00:28:27 GMT

I am using OpenMP and Intel Fortran within Visual Studio 2010 Ultimate. I am calling some functions that are exported from a homemade DLL using the attribute DLLEXPORT and aliases. I use DLLIMPORT for the importation. No problem there.

The problem comes when I try using an OpenMP sentinel (!$, without omp, as in !$ call omp_set_num_threads(4) for instance) right after those DLLIMPORT statements. The conditional compilation that is supposed to be performed by the compiler when using /Qopenmp does not work, and the statements seem to be ignored. However, if I have any standard Fortran statement between the !DEC$ and !$, no problem anymore. Same if the openMP statement is an actual openMP directive, usig !$omp instead of just !$. To resume:

      PROGRAM main

        !$ use omp_lib

        integer :: i

        !$ print*, 'OMP 1'
        !DEC$ ATTRIBUTES DLLIMPORT, ALIAS : 'func1'  :: func1
        !$ print*, 'OMP 2'

        i = 5
        !$ print*, 'OMP 3'

      end program

outputs: 'OMP 1'
'OMP 3'

I have not found any references to this problem anywhere else, or any doc explicitly stating that an openMP sentinel should not directly follow a !DEC$ attributes statement, so I thought that maybe it was a bug that had not been discovered yet.

Looks like an obscure bug

pbkenned1 — Tue, 14 Oct 2014 14:25:32 GMT

Looks like an obscure bug with conditional compilation that hasn't been reported previously. I'll discuss with the team and follow up.

Patrick

Apparently this is a compiler

pbkenned1 — Wed, 15 Oct 2014 19:16:00 GMT

Apparently this is a compiler front end bug, and it has been reported to compiler engineering (internal tracking ID DPD200362090). I'll keep this thread updated with news from the developers.

Patrick

Thank you, Patrick!

Pellegrini__Etienne — Wed, 15 Oct 2014 19:18:29 GMT

Thank you, Patrick!

This issue has been fixed in

pbkenned1 — Wed, 22 Oct 2014 16:21:50 GMT

This issue has been fixed in a future version of the compiler. I'll identify the version with the fix when it becomes available.

Patrick

This is fixed in the 16.0

pbkenned1 — Wed, 28 Oct 2015 20:41:23 GMT

This is fixed in the 16.0 compiler, so I am closing this ticket now.

C:\ISN_Forums\U533490>ifort -Qopenmp foo.f90
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 16.0.0.110 Build 20150815
Copyright (C) 1985-2015 Intel Corporation. All rights reserved.

-out:foo.exe
-subsystem:console
-defaultlib:libiomp5md.lib
-nodefaultlib:vcomp.lib
-nodefaultlib:vcompd.lib
foo.obj

C:\ISN_Forums\U533490>foo.exe
OMP 1
OMP 2
OMP 3

C:\ISN_Forums\U533490>