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Description for the new shufflevector instruction I'm adding. 

llvm-svn: 27502
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Chris Lattner 2006-04-08 00:13:41 +00:00
parent ac847268c5
commit 016a0e50a5
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llvm/docs/LangRef.html
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@ -111,6 +111,7 @@
<li><a href="#i_vselect">'<tt>vselect</tt>' Instruction</a></li>
<li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
<li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
<li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
<li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
<li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
</ol>
@ -1135,6 +1136,12 @@ following is the syntax for constant expressions:</p>
<dd>Perform the <a href="#i_insertelement">insertelement
operation</a> on constants.
<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
<dd>Perform the <a href="#i_shufflevector">shufflevector
operation</a> on constants.
<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
@ -2608,6 +2615,58 @@ exceeds the length of <tt>val</tt>, the results are undefined.
</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
<pre>
&lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x uint&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
</pre>
<h5>Overview:</h5>
<p>
The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
from two input vectors, returning a vector of the same type.
</p>
<h5>Arguments:</h5>
<p>
The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
with types that match each other and types that match the result of the
instruction. The third argument is a shuffle mask, which has the same number
of elements as the other vector type, but whose element type is always 'uint'.
</p>
<p>
The shuffle mask operand is required to be a constant vector with either
constant integer or undef values.
</p>
<h5>Semantics:</h5>
<p>
The elements of the two input vectors are numbered from left to right across
both of the vectors. The shuffle mask operand specifies, for each element of
the result vector, which element of the two input registers the result element
gets. The element selector may be undef (meaning "don't care") and the second
operand may be undef if performing a shuffle from only one vector.
</p>
<h5>Example:</h5>
<pre>
%result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; %v2, <4 x uint> <uint 0, uint 4, uint 1, uint 5> <i>; yields &lt;4 x int&gt;</i>
%result = shufflevector &lt;4 x int&gt; %v1, &lt;4 x int&gt; undef, <4 x uint> <uint 0, uint 1, uint 2, uint 3> <i>; yields &lt;4 x int&gt;</i> - Identity shuffle.
</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">