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UNWIND MARKED LOOPS

Syntax:

UNWIND ALL LOOPS UNWIND MARKED LOOPS UNWIND LOOPS [AS] MARKED DO NOT UNWIND LOOPS

Function:

The command UNWIND ALL LOOPS unwinds all DO loops with constant bounds and strides in the code.

The command UNWIND MARKED LOOPS or UNWIND LOOPS AS MARKED instructs FPT to unwind DO loops marked in the program text by the command UNWIND. UNWIND is written in a comment immediately before the DO statement which begins the loop.

Loops may be unwound, starting from the outer loops and working inwards, or starting from the inner loops and working outwards. This is important for two reasons. If the bounds or stride of an inner loop depend on a DO loop index in the outer loop, the outer loop must be unwound first so that the value of the index is available. If loop unwinding is limited by specifying a maximum number of statements, more efficient code is generated if the inner loops are unwound first. The order of unwinding is specified by the commands UNWIND INNER LOOPS FIRST and UNWIND OUTER LOOPS FIRST.

Loop unwinding is suppressed by the command DO NOT UNWIND LOOPS.

Note that loop unwinding is also suppressed by the command IGNORE COMMANDS IN THE CODE.

Where to use this command:

Operating system command line	Yes
Configuration file, config.fsp	Yes
Specification (FSP) files, *.fsp	Yes
Interactively, to FPT> prompt:	Yes
Interactive command files	Yes
Embedded in the Fortran code	Yes

Default:

UNWIND MARKED LOOPS

(Note that defaults may be changed in the configuration file)

See also:

IGNORE COMMANDS IN THE CODE

UNWIND

UNWIND INNER LOOPS FIRST

UNWIND OUTER LOOPS FIRST