Sun Studio 12 Update 1: Fortran User's Guide

3.4.13 –depend[={yes|no}]

Analyze loops for inter-iteration data dependencies and performs loop restructuring. Loop restructuring includes loop interchange, loop fusion, scalar replacement, and elimination of "dead" array assignments.

On SPARC platforms, -xdepend is turned on for all optimization levels -xO3 and above, and is off for lower opt levels. Also, an explicit setting of -xdepend overrides any implicit setting.

On x86 platforms, if optimization is not at -xO3 or higher, the compiler raises the optimization to -xO3 and issues a warning.

If you do not specify -xdepend, the default is -xdepend=no which means the compiler does not analyze loops for data dependencies. If you specify -xdepend but do not specify an argument, the compiler sets the option to -xdepend=yes which means the compiler analyzes loops for data dependencies.

Dependency analysis is included in -xautopar. The dependency analysis is done at compile time. Dependency analysis may help on single-processor systems. However, if you try -xdepend on single-processor systems, you should not also specify -xautopar , otherwise the -xdepend optimization is done for multiple-processor systems.