Intel® Fortran Compiler 17.0 Developer Guide and Reference
This topic only applies when targeting Intel® Many Integrated Core Architecture (Intel® MIC Architecture).
This topic only applies to the Intel® Xeon Phi™ coprocessor x100 product family (formerly code name Knights Corner).
You can write functions that you intend to run on a target, and sections of offloaded code, to take advantage of target-specific functions.
When the compiler generates code for the coprocessor, it defines a macrodirective specific to the coprocessor architecture, for example __MIC__ for the Intel® Xeon Phi™ coprocessor x100 product family (formerly code name Knights Corner) . You can then write target-specific code within a !DIR$ if defined __MIC__ section.
Do not use coprocessor-specific directives inside the statement following a !DIR$ OMP OFFLOAD statement. You can, however, use them in a subprogram called from the directive.
The implementation of the class F32vec is specialized for the CPU and the coprocessor. The offloaded code can use the specialized version if it runs on the coprocessor. If the offload fails and the construct runs on the CPU, it uses the CPU version.
!DIR$ ATTRIBUTES OFFLOAD : mic :: foo
integer function foo()
implicit none
!DIR$ if defined (__MIC__)
foo = 1 ! Code is running on coprocessor
!DIR$ else
foo = 0 ! Code is running on host
!DIR$ endif
end function foo
program main
implicit none
! Local variables
integer :: result
integer :: foo
!DIR$ ATTRIBUTES OFFLOAD : mic :: foo
! Call foo on host
result = foo()
! Print results
if ( result ) then
write (*,*) "Code ran on coprocessor"
else
write (*,*) "Code ran on host"
end if
! Call foo on MIC
!DIR$ OFFLOAD TARGET(mic)
result = foo()
! Print results
if ( result ) then
write (*,*) "Code ran on coprocessor"
else
write (*,*) "Code ran on host"
end if
end program main