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- <title>The LLVM Alias Analysis Infrastructure</title>
+ <title>LLVM Alias Analysis Infrastructure</title>
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- The LLVM Alias Analysis Infrastructure
+ LLVM Alias Analysis Infrastructure
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<ol>
<ul>
<li><a href="#impls">Available <tt>AliasAnalysis</tt> implementations</a></li>
<li><a href="#aliasanalysis-xforms">Alias analysis driven transformations</a></li>
- <li><a href="#aliasanalysis-debug">Clients for debugging and evaluation of implementations</a></li>
+ <li><a href="#aliasanalysis-debug">Clients for debugging and evaluation of
+ implementations</a></li>
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+<div class="doc_subsubsection">
+ <a name="globalsmodref">The <tt>-globalsmodref-aa</tt> pass</a>
+</div>
+
+<div class="doc_text">
+
+<p>This pass implements a simple context-sensitive mod/ref and alias analysis
+for internal global variables that don't "have their address taken". If a
+global does not have its address taken, the pass knows that no pointers alias
+the global.
+</p>
+
+<p>The real power of this pass is that it provides context-sensitive mod/ref
+information for call instructions. This allows the optimizer to know that
+calls to a function do not clobber or read the value of the global, allowing
+loads and stores to be eliminated.</p>
+
+<p>Note that this pass is somewhat limited in its scope (only support
+non-address taken globals), but is very quick analysis.</p>
+</div>
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