<html lang="en">
<head>
<title>LTO - GNU Compiler Collection (GCC) Internals</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="GNU Compiler Collection (GCC) Internals">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="prev" href="Plugins.html#Plugins" title="Plugins">
<link rel="next" href="Match-and-Simplify.html#Match-and-Simplify" title="Match and Simplify">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1988-2015 Free Software Foundation, Inc.
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 the section entitled
``GNU Free Documentation License''.
(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.-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="LTO"></a>
<p>
Next: <a rel="next" accesskey="n" href="Match-and-Simplify.html#Match-and-Simplify">Match and Simplify</a>,
Previous: <a rel="previous" accesskey="p" href="Plugins.html#Plugins">Plugins</a>,
Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
<hr>
</div>
<h2 class="chapter">24 Link Time Optimization</h2>
<p><a name="index-lto-5103"></a><a name="index-whopr-5104"></a><a name="index-wpa-5105"></a><a name="index-ltrans-5106"></a>
Link Time Optimization (LTO) gives GCC the capability of
dumping its internal representation (GIMPLE) to disk,
so that all the different compilation units that make up
a single executable can be optimized as a single module.
This expands the scope of inter-procedural optimizations
to encompass the whole program (or, rather, everything
that is visible at link time).
<ul class="menu">
<li><a accesskey="1" href="LTO-Overview.html#LTO-Overview">LTO Overview</a>: Overview of LTO.
<li><a accesskey="2" href="LTO-object-file-layout.html#LTO-object-file-layout">LTO object file layout</a>: LTO file sections in ELF.
<li><a accesskey="3" href="IPA.html#IPA">IPA</a>: Using summary information in IPA passes.
<li><a accesskey="4" href="WHOPR.html#WHOPR">WHOPR</a>: Whole program assumptions,
linker plugin and symbol visibilities.
<li><a accesskey="5" href="Internal-flags.html#Internal-flags">Internal flags</a>: Internal flags controlling <code>lto1</code>.
</ul>
</body></html>