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Added description of invariant.load metadata to LangRef. It was added to the compiler in r144100

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150257 91177308-0d34-0410-b5e6-96231b3b80d8
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Pete Cooper 2012-02-10 18:13:54 +00:00
parent 1de886c1fa
commit f95acc6d02
1 changed files with 9 additions and 1 deletions
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docs/LangRef.html
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@ -4681,7 +4681,7 @@ IfUnequal:
<h5>Syntax:</h5>
<pre>
&lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
&lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;][, !invariant.load !&lt;index&gt;]
&lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
!&lt;index&gt; = !{ i32 1 }
</pre>
@ -4726,6 +4726,14 @@ IfUnequal:
The code generator may select special instructions to save cache bandwidth,
such as the <tt>MOVNT</tt> instruction on x86.</p>
<p>The optional <tt>!invariant.load</tt> metadata must reference a single
metatadata name &lt;index&gt; corresponding to a metadata node with no
entries. The existence of the <tt>!invariant.load</tt> metatadata on the
instruction tells the optimizer and code generator that this load address
points to memory which does not change value during program execution.
The optimizer may then move this load around, for example, by hoisting it
out of loops using loop invariant code motion.</p>
<h5>Semantics:</h5>
<p>The location of memory pointed to is loaded. If the value being loaded is of
scalar type then the number of bytes read does not exceed the minimum number