129 lines
6.4 KiB
HTML
129 lines
6.4 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<!-- Copyright (C) 1988-2016 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "Funding Free Software", the Front-Cover
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Texts being (a) (see below), and with the Back-Cover Texts being (b)
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(see below). A copy of the license is included in the section entitled
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"GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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funds for GNU development. -->
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<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>GNU Compiler Collection (GCC) Internals: Tree SSA</title>
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<meta name="description" content="GNU Compiler Collection (GCC) Internals: Tree SSA">
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<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Tree SSA">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="index.html#Top" rel="up" title="Top">
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<link href="Annotations.html#Annotations" rel="next" title="Annotations">
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<link href="Statement-and-operand-traversals.html#Statement-and-operand-traversals" rel="prev" title="Statement and operand traversals">
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</head>
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<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
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<a name="Tree-SSA"></a>
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<div class="header">
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<p>
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Next: <a href="RTL.html#RTL" accesskey="n" rel="next">RTL</a>, Previous: <a href="GIMPLE.html#GIMPLE" accesskey="p" rel="prev">GIMPLE</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<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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</div>
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<hr>
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<a name="Analysis-and-Optimization-of-GIMPLE-tuples"></a>
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<h2 class="chapter">12 Analysis and Optimization of GIMPLE tuples</h2>
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<a name="index-Tree-SSA"></a>
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<a name="index-Optimization-infrastructure-for-GIMPLE"></a>
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<p>GCC uses three main intermediate languages to represent the program
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during compilation: GENERIC, GIMPLE and RTL. GENERIC is a
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language-independent representation generated by each front end. It
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is used to serve as an interface between the parser and optimizer.
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GENERIC is a common representation that is able to represent programs
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written in all the languages supported by GCC.
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</p>
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<p>GIMPLE and RTL are used to optimize the program. GIMPLE is used for
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target and language independent optimizations (e.g., inlining,
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constant propagation, tail call elimination, redundancy elimination,
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etc). Much like GENERIC, GIMPLE is a language independent, tree based
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representation. However, it differs from GENERIC in that the GIMPLE
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grammar is more restrictive: expressions contain no more than 3
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operands (except function calls), it has no control flow structures
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and expressions with side-effects are only allowed on the right hand
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side of assignments. See the chapter describing GENERIC and GIMPLE
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for more details.
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</p>
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<p>This chapter describes the data structures and functions used in the
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GIMPLE optimizers (also known as “tree optimizers” or “middle
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end”). In particular, it focuses on all the macros, data structures,
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functions and programming constructs needed to implement optimization
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passes for GIMPLE.
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</p>
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<table class="menu" border="0" cellspacing="0">
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<tr><td align="left" valign="top">• <a href="Annotations.html#Annotations" accesskey="1">Annotations</a>:</td><td> </td><td align="left" valign="top">Attributes for variables.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="SSA-Operands.html#SSA-Operands" accesskey="2">SSA Operands</a>:</td><td> </td><td align="left" valign="top">SSA names referenced by GIMPLE statements.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="SSA.html#SSA" accesskey="3">SSA</a>:</td><td> </td><td align="left" valign="top">Static Single Assignment representation.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Alias-analysis.html#Alias-analysis" accesskey="4">Alias analysis</a>:</td><td> </td><td align="left" valign="top">Representing aliased loads and stores.
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</td></tr>
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<tr><td align="left" valign="top">• <a href="Memory-model.html#Memory-model" accesskey="5">Memory model</a>:</td><td> </td><td align="left" valign="top">Memory model used by the middle-end.
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</td></tr>
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</table>
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<hr>
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<div class="header">
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<p>
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Next: <a href="RTL.html#RTL" accesskey="n" rel="next">RTL</a>, Previous: <a href="GIMPLE.html#GIMPLE" accesskey="p" rel="prev">GIMPLE</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<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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</div>
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</body>
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</html>
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