Intel® C++ Compiler 16.0 User and Reference Guide

Profile-Guided Optimization Report

The PGO report can help identify where and how the compiler used profile information to optimize the source code. The PGO report is most useful when combined with the PGO compilation steps outlined in the topic, Profile an Application. Without the profiling data generated during the application profiling process the report will generally not provide useful information.

Combine the final PGO step with the reporting options by including -prof-use (Linux* and OS X*) or /Qprof-use (Windows*). The following syntax examples demonstrate how to run the report using the combined options.

Operating System Syntax Examples

Linux* OS

icpc -prof-use -opt-report-phase=pgo pgotools_sample.c

OS X*

icl++ -prof-use -opt-report-phase=pgo pgotools_sample.c //with CLANG compiler

icpc -prof-use -opt-report-phase=pgo pgotools_sample.c //with EDG compiler

Windows* OS

icl /Qprof-use /Qopt-report-phase:pgo pgotools_sample.c

By default the PGO report generates a medium level of detail (where the [Q]opt-report argument n=2). You can use the -opt-report= n (Linux and OS X) or /Qopt-report:n option along with the [Q]opt-report-phase option if you want a greater or lesser level of diagnostic detail.

The output, by default, comes out to a file with the same name as the object file but with an .optrpt extension and is written into the same directory as the object file. Using the entries in the example above, the output file will be pgotools_sample.optrpt. Use the -opt-report-file (Linux and OS X) or the /Qopt-report-file (Windows) option to specify any other name for the output file that captures the report results, or to specify that the output should go to stdout or stderr.

See Also