Subject: hpff-doc: Comments on Extended Mapping

From: Thomas Brandes <[email-masked]>
Date: Fri, 13 Sep 1996 12:21:28 +0200

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1) RANGE DIRECTIVE (8.11)
   
Proposal: BLOCK, BLOCK(m) are also compatible with GEN_BLOCK

I believe that this will not make any difference for the compiler.

2) Shadow Width Declarations (8.12)

Sorry, I am absolutely not happy with it.

a) What about aligned arrays?

   Chapter 2 forces the user to use more the ALIGN directive. What is
   the shadow width of an aligned array ?

   If shadow edges are inherited, this will add shadow edges for a lot
   of arrays where this is not really required.

b) What about dummy arrays ?

   Can we specify shadow edges for dummy arrays ?

   This can be useful in certain cases.

c) Shadow edges for serial arrays ?

         REAL A(N)
   !HPF$ DISTRIBUTE A(*)
         A = CSHIFT (A,1) + CSHIFT(A,-1)

   A shadow edge is also useful for the array A as the code generation
   might be less complex.

   A(0) = A(N)
   A(N+1) = A(1)
   FORALL (I=1:N) A(I) = A(I-1) + A(I+1)

Proposal: insert a directive that is related to arrays instead of 
          distributions.

   !HPF$ SHADOW <shadow_decl_list>

   <shadow_decl> :: array_name '(' shadow_spec_list ')'

   <shadow_spec> :: [int_expr]
                    int_expr : int_expr
                    LOW_SHADOW = int-expr [: HIGH_SHADOW = int-expr]
                    HIGH_SHADOW = int-expr [: LOW_SHADOW = int-expr]

   Example:

   !HPF$ SHADOW A(3,1:2,HIGH_SHADOW=3)
   !HPF$ SHADOW B(,LOW_SHADOW=1)

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