Sun Studio 12: C User's Guide

B.2.134 -xreduction

(SPARC) Turns on reduction recognition during automatic parallelization. -xreduction must be specified with -xautopar, or -xparallel otherwise the compiler issues a warning.

When reduction recognition is enabled, the compiler parallelizes reductions such as dot products, maximum and minimum finding. These reductions yield different roundoffs than obtained by unparallelized code.