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MLton
20241230
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<h1>CommonSubexp</h1>
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<p><a href="#">CommonSubexp</a> is an optimization pass for the <a href="SSA">SSA</a>
<a href="IntermediateLanguage">IntermediateLanguage</a>, invoked from <a href="SSASimplify">SSASimplify</a>.</p>
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<h2 id="_description">Description</h2>
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<p>It eliminates instances of common subexpressions.</p>
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<h2 id="_implementation">Implementation</h2>
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<p><a href="https://github.com/MLton/mlton/blob/master/mlton/ssa/common-subexp.fun"><code>common-subexp.fun</code></a></p>
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<h2 id="_details_and_notes">Details and Notes</h2>
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<p>In addition to getting the usual sorts of things like</p>
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<p></p>
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<pre>(w + 0wx1) + (w + 0wx1)</pre>
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<p>rewritten to</p>
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<pre>let val w' = w + 0wx1 in w' + w' end</pre>
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<p>it also gets things like</p>
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<pre>val a = Array_uninit n
val b = Array_length a</pre>
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<p>rewritten to</p>
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<pre>val a = Array_uninit n
val b = n</pre>
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Last updated Thu Oct 21 15:53:06 2021 -0400 by Matthew Fluet.
<a href="https://github.com/MLton/mlton/commits/master/doc/guide/src/CommonSubexp.adoc">Log</a>
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