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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - LibCallSimplifier::optimizeSinCosPi walks through all users of a ConstantFP"
href="https://llvm.org/bugs/show_bug.cgi?id=30557">30557</a>
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<th>Summary</th>
<td>LibCallSimplifier::optimizeSinCosPi walks through all users of a ConstantFP
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Transformation Utilities
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>dexonsmith@apple.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=17375" name="attach_17375" title="Patch to stop optimizing sinpi/cospi of a ConstantFP into sincospi.">attachment 17375</a> <a href="attachment.cgi?id=17375&action=edit" title="Patch to stop optimizing sinpi/cospi of a ConstantFP into sincospi.">[details]</a></span>
Patch to stop optimizing sinpi/cospi of a ConstantFP into sincospi.
LibCallSimplifier::optimizeSinCosPi walks through all users of the arguments in
calls to @llvm.cospi and @llvm.sinpi. Since these arguments might be
ConstantFP, which is owned by the context, this could take an arbitrarily long
time.
Moreover, this is blocking the removal of use-lists from ConstantData in <a class="bz_bug_link
bz_status_NEW "
title="NEW --- - ConstantData should not have use-lists"
href="show_bug.cgi?id=30513">bug
30513</a>.
There are a few possible solutions:
- Stop performing this optimization on ConstantData (i.e., ConstantFP). I've
attached a patch that does this, but I doubt it's really what we want.
- Move this optimization to its own pass that walks through the instructions in
a function and keeps a map of the cospi/sinpi calls it has found so far, lazily
replacing them with sincospi when it gets to a matching pair.
- Move this optimization to a similar pass and add this functionality.</pre>
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