[MPI3 Fortran] Fortran extra_state argument to MPIattributefunctions

Jim Xia jimxia at ca.ibm.com
Thu May 28 12:37:54 CDT 2009

mpi3-fortran-bounces at lists.mpi-forum.org wrote on 05/28/2009 01:17:13 PM:

> Besides the more formal methods mentioned by Aleks below, there is a 
> common programming style approach to solve this problem: put the 
> variable extra in a module.  The compiler has to assume that any 
> non-intrinsic procedure reference might access the module, and hence 
> access or modify the variable.  This technique generally avoids 
> performance hits  that might be associated with some others -

Using module variables is a nice way to go.  But I don't think that solves 
all the aliasing problems.

>                                                                 in 
> particular, the VOLATILE attribute can shut down almost all optimization 

> for a variable.

Where did you get that idea from?  Does anything associated (any kind of 
association) with this variable also inherit VOLATILE?  I don't see 
VOLATILE being a viable solution.

Also to Aleks:  We've discussed this TARGET attribute for too long.  Let's 
agree to disagree :-).


Jim Xia

XL Fortran Compiler Test
IBM Toronto Lab at 8200 Warden Ave, Markham, On, L6G 1C7
Phone (905) 413-3444  Tie-line 313-3444
email: jimxia at ca.ibm.com
D2/YF7/8200 /MKM

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