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Subject: [OMPI users] is loop unrolling safe for MPI logic?
From: Anton Shterenlikht (mexas_at_[hidden])
Date: 2010-07-17 04:22:57

I'm using mpif90 with Intel 10 fortran complier:

% mpif90 -compile_info
ifort -I/usr/mpi/qlogic//include/mpich/intel10/x86_64 -c -I/usr/mpi/qlogic//include

If I don't specify any compiler options, the
compiler vectorises some loops:

% mpif90 p-grains1.f90
p-grains1.f90(123): (col. 1) remark: LOOP WAS VECTORIZED.
p-grains1.f90(250): (col. 35) remark: LOOP WAS VECTORIZED.

Is loop vectorisation/unrolling safe for MPI logic?
I presume it is, but are there situations where
loop vectorisation could e.g. violate the order
of execution of MPI calls?

many thanks

Anton Shterenlikht
Room 2.6, Queen's Building
Mech Eng Dept
Bristol University
University Walk, Bristol BS8 1TR, UK
Tel: +44 (0)117 331 5944
Fax: +44 (0)117 929 4423