GNU Compiler Collection Flags

Flag descriptions for GCC, the GNU Compiler Collection

Note: The GNU Compiler Collection provides a wide array of compiler options, described in detail and readily available at and This SPEC CPU flags file contains excerpts from and brief summaries of portions of that documentation.

SPEC's modifications are:
Copyright (C) 2006-2017 Standard Performance Evaluation Corporation

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Funding Free Software", the Front-Cover Texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in your SPEC CPU kit at $SPEC/Docs/licenses/FDL.v1.3 and on the web at A copy of "Funding Free Software" is on your SPEC CPU kit at $SPEC/Docs/licenses/FundingFreeSW and on the web at

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.


Selecting one of the following will take you directly to that section:

Optimization Flags

Portability Flags

Compiler Flags

Other Flags

Commands and Options Used to Submit Benchmark Runs

SPECrate runs might use one of these methods to bind processes to specific processors, depending on the config file.

Commands and Options Used for Feedback-Directed Optimization

No special commands are needed for feedback-directed optimization, other than the compiler profile  flags.

Shell, Environment, and Other Software Settings

One or more of the following may have been used in the run. If so, it will be listed in the notes sections. Here is a brief guide to understanding them: