Performance impact of how a large array is accessed

[PierU]

@rdryne

I find this particularly strange because array hist is allocated the main program — so it knows the array size there — and the call to blah occurs in the main program of this toy code. But, call blah( hist( :,0:,i )…) produces no array copy while call blah( hist( 1:6,0:nhistpoints,i ),…) does produce an array copy. It’s as though the presence of CONTIGUOUS in subroutine blah causes gfortran to make an array copy even though it has all the information needed (in main where blah is called) to see that the array argument is contiguous and a copy is not needed.

If you’re correct, you should fill a bug report. It’s not a bug per se, but at least an unexpected behavior.