J3/17-244
To:        J3 Members
From:      Lorri Menard
Subject:   Comment GB038; regarding DEFAULT (NONE)
Date: 2017 October 17
References: N2141, 17-007r2

1. Introduction:
~~~~~~~~~~~~~~~~~

[191:17] 11.1.7.2 Form of the DO construct
 The syntax permits DEFAULT (NONE) to appear more than once in a single
concurrent header in a DO CONCURRENT statement.


2. Discussion:
~~~~~~~~~~~~~~~~~

In subgroup we then asked "Is it legal to have LOCAL, LOCAL_INIT, and
SHARED repeated in a given concurrent-locality?"  The syntax certainly
permits it and it matches OpenMP's behavior.  However we could not
come up with any other Fortran statements or constructs where keywords
can be repeated.

Straw vote relative to locality specs on a DO CONCURRENT statement
    1) No locality spec should be repeated
    2) Only DEFAULT(NONE) cannot be repeated
    3) They all can be repeated (status quo)
    4) Undecided


3. Possible edits
~~~~~~~~~~~~~~~~~

If straw-proposal 1 wins:

After C1126, insert new constraint:
[191:17]+ "C1126a No <<locality-spec>> shall appear more than once in
a given <<concurrent-locality>>."


If straw-proposal 2 wins:

After C1126, insert new constraint:
[191:17]+ "C1126a The DEFAULT ( NONE ) <<locality-spec>> shall not appear
more than once in a given <<concurrent-locality>>."

If straw-proposal 3 wins:

 No edits are required

If straw-proposal 4 wins:

  Subgroup will ponder deeply the implications.