Added the ability to xfail based on llvmgcc version
[oota-llvm.git] / docs / Lexicon.html
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
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3 <head>
4   <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
5   <title>The LLVM Lexicon</title>
6   <link rel="stylesheet" href="llvm.css" type="text/css">
7   <meta name="author" content="Various">
8   <meta name="description" 
9   content="A glossary of terms used with the LLVM project.">
10 </head>
11 <body>
12 <div class="doc_title">The LLVM Lexicon</div>
13 <p class="doc_warning">NOTE: This document is a work in progress!</p>
14 <!-- *********************************************************************** -->
15 <div class="doc_section">Table Of Contents</div>
16 <!-- *********************************************************************** -->
17 <div class="doc_text">
18   <table>
19     <tr><th colspan="8"><b>- <a href="#A">A</a> -</b></th></tr>
20     <tr>
21       <td><a href="#ADCE">ADCE</a></td>
22     </tr>
23     <tr><th colspan="8"><b>- <a href="#B">B</a> -</b></th></tr>
24     <tr>
25       <td><a href="#BURS">BURS</a></td>
26     </tr>
27     <tr><th colspan="8"><b>- <a href="#C">C</a> -</b></th></tr>
28     <tr>
29       <td><a href="#CSE">CSE</a></td>
30     </tr>
31     <tr><th colspan="8"><b>- <a href="#D">D</a> -</b></th></tr>
32     <tr>
33       <td><a href="#DSA">DSA</a></td>
34       <td><a href="#DSE">DSE</a></td>
35     </tr>
36     <tr><th colspan="8"><b>- <a href="#I">I</a> -</b></th></tr>
37     <tr>
38       <td><a href="#IPA">IPA</a></td>
39       <td><a href="#IPO">IPO</a></td>
40     </tr>
41     <tr><th colspan="8"><b>- <a href="#L">L</a> -</b></th></tr>
42     <tr>
43       <td><a href="#LICM">LICM</a></td>
44       <td><a href="#Load-VN">Load-VN</a></td>
45     </tr>
46     <tr><th colspan="8"><b>- <a href="#P">P</a> -</b></th></tr>
47     <tr>
48       <td><a href="#PRE">PRE</a></td>
49     </tr>
50     <tr><th colspan="8"><b>- <a href="#R">R</a> -</b></th></tr>
51     <tr>
52       <td><a href="#Reassociation">Reassociation</a></td>
53     </tr>
54     <tr><th colspan="8"><b>- <a href="#S">S</a> -</b></th></tr>
55     <tr>
56       <td><a href="#SCC">SCC</a></td>
57       <td><a href="#SCCP">SCCP</a></td>
58       <td><a href="#SRoA">SRoA</a></td>
59       <td><a href="#SSA">SSA</a></td>
60     </tr>
61   </table>
62 </div>
63
64 <!-- *********************************************************************** -->
65 <div class="doc_section">Definitions</div>
66 <!-- *********************************************************************** -->
67 <!-- _______________________________________________________________________ -->
68 <div class="doc_subsection"><a name="A">- A -</a></div>
69 <div class="doc_text">
70   <dl>
71     <dt><a name="ADCE"><b>ADCE</b></a></dt>
72     <dd>Aggressive Dead Code Elimination</dd>
73   </dl>
74 </div>
75 <!-- _______________________________________________________________________ -->
76 <div class="doc_subsection"><a name="B">- B -</a></div>
77 <div class="doc_text">
78   <dl>
79     <dt><a name="BURS"><b>BURS</b></a></dt>
80     <dd>Bottom Up Rewriting System - A method of instruction selection for
81         code generation.  An example is the <a 
82 href="http://www.program-transformation.org/Transform/BURG">BURG</a> tool.</dd>
83   </dl>
84 </div>
85 <!-- _______________________________________________________________________ -->
86 <div class="doc_subsection"><a name="C">- C -</a></div>
87 <div class="doc_text">
88   <dl>
89     <dt><a name="CSE"><b>CSE</b></a></dt>
90     <dd>Common Subexpression Elimination. An optimization that removes common
91     subexpression compuation. For example <tt>(a+b)*(a+b)</tt> has two
92     subexpressions that are the same: <tt>(a+b)</tt>. This optimization would
93     perform the addition only once and then perform the multiply (but only if
94     its compulationally correct/safe).
95   </dl>
96 </div>
97 <!-- _______________________________________________________________________ -->
98 <div class="doc_subsection"><a name="D">- D -</a></div>
99 <div class="doc_text">
100   <dl>
101     <dt><a name="DSA"><b>DSA</b></a></dt>
102     <dd>Data Structure Analysis</dd>
103     <dt><a name="DSE"><b>DSE</b></a></dt>
104     <dd>Dead Store Elimination</dd>
105   </dl>
106 </div>
107 <!-- _______________________________________________________________________ -->
108 <div class="doc_subsection"><a name="I">- I -</a></div>
109 <div class="doc_text">
110   <dl>
111     <dt><a name="IPA"><b>IPA</b></a></dt>
112     <dd>Inter-Procedural Analysis. Refers to any variety of code analysis that
113     occurs between procedures, functions or compilation units (modules).</dd>
114     <dt><a name="IPO"><b>IPO</b></a></dt>
115     <dd>Inter-Procedural Optimization. Refers to any variety of code
116     optimization that occurs between procedures, functions or compilation units
117     (modules).</dd>
118   </dl>
119 </div>
120 <!-- _______________________________________________________________________ -->
121 <div class="doc_subsection"><a name="L">- L -</a></div>
122 <div class="doc_text">
123   <dl>
124     <dt><a name="LICM"><b>LICM</b></a></dt>
125     <dd>Loop Invariant Code Motion</dd>
126     <dt><a name="Load-VN"><b>Load-VN</b></a></dt>
127     <dd>Load Value Numbering</dd>
128   </dl>
129 </div>
130
131 <!-- _______________________________________________________________________ -->
132 <div class="doc_subsection"><a name="P">- P -</a></div>
133 <div class="doc_text">
134   <dl>
135     <dt><a name="PRE"><b>PRE</b></a></dt>
136     <dd>Partial Redundancy Elimination</dd>
137   </dl>
138 </div>
139
140 <!-- _______________________________________________________________________ -->
141 <div class="doc_subsection"><a name="R">- R -</a></div>
142 <div class="doc_text">
143   <dl>
144     <dt><a name="Reassociation"><b>Reassociation</b></a></dt> <dd>Rearranging
145     associative expressions to promote better redundancy elimination and other
146     optimization.  For example, changing (A+B-A) into (B+A-A), permitting it to
147     be optimized into (B+0) then (B).
148   </dl>
149 </div>
150
151 <!-- _______________________________________________________________________ -->
152 <div class="doc_subsection"><a name="S">- S -</a></div>
153 <div class="doc_text">
154   <dl>
155     <dt><a name="SCC"><b>SCC</b></a></dt>
156     <dd>Strongly Connected Component</dd>
157     <dt><a name="SCCP"><b>SCCP</b></a></dt>
158     <dd>Sparse Conditional Constant Propagation</dd>
159     <dt><a name="SRoA"><b>SRoA</b></a></dt>
160     <dd>Scalar Replacement of Aggregates</dd>
161     <dt><a name="SSA"><b>SSA</b></a></dt>
162     <dd>Static Single Assignment</dd>
163   </dl>
164 </div>
165 <!-- *********************************************************************** -->
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