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Next: <a href="Machine-Desc.html#Machine-Desc" accesskey="n" rel="next">Machine Desc</a>, Previous: <a href="Control-Flow.html#Control-Flow" accesskey="p" rel="prev">Control Flow</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Analysis-and-Representation-of-Loops"></a>
<h2 class="chapter">16 Analysis and Representation of Loops</h2>

<p>GCC provides extensive infrastructure for work with natural loops, i.e.,
strongly connected components of CFG with only one entry block.  This
chapter describes representation of loops in GCC, both on GIMPLE and in
RTL, as well as the interfaces to loop-related analyses (induction
variable analysis and number of iterations analysis).
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="Loop-representation.html#Loop-representation" accesskey="1">Loop representation</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Representation and analysis of loops.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Loop-querying.html#Loop-querying" accesskey="2">Loop querying</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Getting information about loops.
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<tr><td align="left" valign="top">&bull; <a href="Loop-manipulation.html#Loop-manipulation" accesskey="3">Loop manipulation</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Loop manipulation functions.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="LCSSA.html#LCSSA" accesskey="4">LCSSA</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Loop-closed SSA form.
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<tr><td align="left" valign="top">&bull; <a href="Scalar-evolutions.html#Scalar-evolutions" accesskey="5">Scalar evolutions</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Induction variables on GIMPLE.
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<tr><td align="left" valign="top">&bull; <a href="loop_002div.html#loop_002div" accesskey="6">loop-iv</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Induction variables on RTL.
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<tr><td align="left" valign="top">&bull; <a href="Number-of-iterations.html#Number-of-iterations" accesskey="7">Number of iterations</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Number of iterations analysis.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Dependency-analysis.html#Dependency-analysis" accesskey="8">Dependency analysis</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Data dependency analysis.
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