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Document llvm.prefetch, patch contributed by Justin Wick!

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20373 91177308-0d34-0410-b5e6-96231b3b80d8
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Chris Lattner 2005-02-28 19:24:19 +00:00
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@ -125,6 +125,7 @@
<ol>
<li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
<li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
<li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
</ol>
</li>
<li><a href="#int_os">Operating System Intrinsics</a>
@ -2499,6 +2500,52 @@ source-language caller.
</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
<pre>
call void (sbyte *, uint, uint)* %llvm.prefetch(sbyte * &lt;address&gt;,
uint &lt;rw&gt;,
uint &lt;locality&gt;)
</pre>
<h5>Overview:</h5>
<p>
The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
a prefetch instruction if supported, otherwise it is a noop. Prefetches have no
behavior affect on the program, but can change the performance characteristics
of the code.
</p>
<h5>Arguments:</h5>
<p>
<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
determining if the fetch should be for a read (0) or write (1), and
<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
locality, to (3) - exteremely local keep in cache. The <tt>rw</tt> and
<tt>locality</tt> arguments must be constant integers.
</p>
<h5>Semantics:</h5>
<p>
This intrinsic does not modify the behavior of the program. In particular,
prefetches cannot trap and do not produce a value. On targets that support this
intrinsic, the prefetch can provide hints to the processor cache for better
performance.
</p>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="int_os">Operating System Intrinsics</a>