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<title>GNU Compiler Collection (GCC) Internals: Compound Lvalues</title>

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<a name="Compound-Lvalues-1"></a>
<h4 class="subsection">11.5.2 Compound Lvalues</h4>
<a name="index-Compound-Lvalues"></a>

<p>Currently compound lvalues involving array and structure field references
are not broken down; an expression like <code>a.b[2] = 42</code> is not reduced
any further (though complex array subscripts are).  This restriction is a
workaround for limitations in later optimizers; if we were to convert this
to
</p>
<div class="smallexample">
<pre class="smallexample">T1 = &amp;a.b;
T1[2] = 42;
</pre></div>

<p>alias analysis would not remember that the reference to <code>T1[2]</code> came
by way of <code>a.b</code>, so it would think that the assignment could alias
another member of <code>a</code>; this broke <code>struct-alias-1.c</code>.  Future
optimizer improvements may make this limitation unnecessary.
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