Re: [Patch, Fortran] Simplify lbound

[Mikael Morin <mikael.morin@sfr.fr>]

Le 25/04/2015 13:33, Thomas Koenig a écrit :
> Hello world,
> 
> this is a simplification for calculating the lboud of assumed-shape
> arrays - it is usually one, or whatever the user specified as
> lower bound (if constant).
> 
Hello,

I've double-checked in the standard, and it seems it is not possible to
simplify after all:

	If ARRAY is a whole array and either ARRAY is an assumed-size
	array of rank DIM or dimension DIM of ARRAY has nonzero extent,
	LBOUND (ARRAY, DIM) has a value equal to the lower bound for
	subscript DIM of ARRAY. Otherwise the result value is 1.

We can't tell whether the array is zero-sized, so we can't tell the
lbound value.


As you may want to simplify in the limited scope of the matmul inlining,
I'm giving comments about the patch (otherwise you can ignore them):
 - No need to check for allocatable or pointer, it should be excluded by
as->type == AS_ASSUMED_SHAPE (but does no harm either).
 - Please modify the early return condition:
     if (as && (as->type == AS_DEFERRED || as->type == AS_ASSUMED_SHAPE
	        || as->type == AS_ASSUMED_RANK))
       return NULL;
   and let the existing code do the simplification work.


Or drop the lbound simplification idea, and fetch the lbound "by hand"
at matmul inline time.

Mikael