Add a preview of two new conversion operators: ptrtoint and inttoptr. Update

the defintion of bitconvert correspondingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31688 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Spencer 2006-11-11 21:00:47 +00:00
parent 0288d18bb6
commit 72679258ff

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@ -124,6 +124,8 @@
<li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
<li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
<li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
<li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
<li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
<li><a href="#i_bitconvert">'<tt>bitconvert .. to</tt>' Instruction</a></li>
</ol>
<li><a href="#otherops">Other Operations</a>
@ -2953,6 +2955,77 @@ the value cannot fit in the floating point value, the results are undefined.</p>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
<pre>
&lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
the integer type <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
<h5>Semantics:</h5>
<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
<tt>ty2</tt> by interpreting the pointer value as an integer and either
truncating or zero extending that value to the size of the integer type. If
<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
are the same size, then nothing is done (<i>no-op cast</i>).</p>
<h5>Example:</h5>
<pre>
%X = ptrtoint int* %X to sbyte <i>; yields truncation on 32-bit</i>
%Y = ptrtoint int* %x to ulong <i>; yields zero extend on 32-bit</i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
<pre>
&lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
a pointer type, <tt>ty2</tt>.</p>
<h5>Arguments:</h5>
<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
value to cast, and a type to cast it to, which must be a
<a href="#t_pointer">pointer</a> type. </tt>
<h5>Semantics:</h5>
<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
<tt>ty2</tt> by applying either a zero extension or a truncation depending on
the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
the size of a pointer then a zero extension is done. If they are the same size,
nothing is done (<i>no-op cast</i>).</p>
<h5>Example:</h5>
<pre>
%X = inttoptr int 255 to int* <i>; yields zero extend on 64-bit</i>
%X = inttoptr int 255 to int* <i>; yields no-op on 32-bit </i>
%Y = inttoptr short 0 to int* <i>; yields zero extend on 32-bit</i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="i_bitconvert">'<tt>bitconvert .. to</tt>' Instruction</a>
@ -2976,10 +3049,12 @@ and the destination type, <tt>ty2</tt>, must be identical.</p>
<h5>Semantics:</h5>
<p>The '<tt>bitconvert</tt>' instruction converts <tt>value</tt> to type
<tt>ty2</tt> as if the value had been stored to memory and read back as type
<tt>ty2</tt>. That is, no bits are changed during the conversion. The
<tt>bitconvert</tt> instruction is the only conversion instruction that permits
<i>no-op casts</i> to be constructed.</p>
<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
this conversion. The conversion is done as if the <tt>value</tt> had been
stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
converted to other pointer types with this instruction. To convert pointers to
other types, use the <a href="#i_inttoptr">inttoptr</a> or
<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
<h5>Example:</h5>
<pre>