HP UX Fortran Software Compatibility directives, Controlling vectorization, Vendor Directive Cray

Description and restrictions

The $HP$ OPTIMIZEdirective allows you to determine which areas of your program that the optimizer will process. Specifying $HP$ OPTIMIZE OFFcauses the following source lines not to be optimized. $HP$ OPTIMIZE ONre-enables optimization for the following source lines.

This directive is effective only if you have used either the -Onor +Onoption when you compiled the program. If you have not specified either option, both $HP$ OPTIMIZE ONand $HP$ OPTIMIZE OFFwill give you level 0 optimization.

The following are supported:

!HP$ OPTIMIZE ON

!HP$ OPTIMIZE OFF !HP$ OPTIMIZE level 1 !HP$ OPTIMIZE level 0 !HP$ OPTIMIZE level 2 !HP$ OPTIMIZE level 1 on !HP$ OPTIMIZE level 0 on !HP$ OPTIMIZE level 2 on !HP$ OPTIMIZE level 1 off !HP$ OPTIMIZE level 0 off !HP$ OPTIMIZE level 2 off

!HP$ optimize assume_no_parameters_overlaps on !HP$ optimize assume_no_parameters_overlaps off

Compatibility directives

HP Fortran supports the compiler directives listed in Table 9-2. These directives are provided for compatibility with programs developed on the platforms listed in the table.

Table 36 Compatibility directives recognized by HP Fortran

Vendor	Directive
Cray	DIR$ NO SIDE EFFECTS
	DIR$ [NO]CONCUR
	DIR$ IVDEP
	FPP$ NODEPCHK
KAP	*$* [NO]CONCURRENTIZE
	*$* [NO]VECTORIZE
VAST	VD$ NODEPCHK

In fixed format, each directive must be preceded by the comment character C, !, or *and must begin in column 1 of the source file. In free format, the directive must be preceded by the Fortran comment character(!).

If an option or argument is included with the directive name, the compiler ignores the directive.

The following sections describes these directives in detail.

Controlling vectorization

HP Fortran can vectorize eligible program loops that operate on vectors. This optimization causes the compiler to replace the loops with calls to selected routines in the Basic Linear Algebra Subroutine (BLAS) library. You can use the *$*[NO]VECTORIZEdirective to enable or disable vectorization. The compiler considers the *$* VECTORIZEdirective as a request to vectorize a loop. If the compiler determines that it cannot profitably or safely vectorize the loop, it ignores the directive.

To use the vectorization directive, you must compile and link with the +Ovectorizeoption. The directive applies to the beginning of the next loop and remains in effect for the rest of the program

128 Using Fortran directives