PGI User's Guide

Accelerator DirectivesAccelerator Directives90This section provides an overview of the Fortran and C directives used to delineate accelerator regions and toaugment information available to the compiler for scheduling of loops and classification of data. For completedescriptions of each accelerator directive, refer to the “PGI Accelerator Directives” section of the PGI CompilerReference Manual.Enable Accelerator DirectivesPGI Accelerator compilers enable accelerator directives with the –ta command line option. For moreinformation on this option as it relates to the Accelerator, refer to “Applicable Command Line Options,” onpage 99.Note_ACCEL macroFormatRulesThe syntax used to define directives allows compilers to ignore accelerator directives if support isdisabled or not provided.The _ACCEL macro name is defined to have a value yyyymm where yyyy is the year and mm is the monthdesignation of the version of the Accelerator directives supported by the implementation. For example, theversion for May, 2009 is 200905. This macro must be defined by a compiler when accelerator directives areenabled.The specific format of the directive depends on the language and the format or form of the source.Directives include a name and clauses, and the format of the directive depends on the type:• C directives, described in “C Directives”• Free-form Fortran directives, described in “Free-Form Fortran Directives”• Fixed-form Fortran directives, described in “Fixed-Form Fortran Directives”NoteThis document uses free form for all PGI Accelerator compiler Fortran directive examples.The following rules apply to all PGI Accelerator compiler directives:• Only one directive-name can be specified per directive.• The order in which clauses appear is not significant.• Clauses may be repeated unless otherwise specified.