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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [Polly] Construction of Boundary Context is very expensive"
href="https://llvm.org/bugs/show_bug.cgi?id=25471">25471</a>
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<th>Summary</th>
<td>[Polly] Construction of Boundary Context is very expensive
</td>
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<th>Product</th>
<td>Projects
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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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
</td>
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<th>Component</th>
<td>Polly
</td>
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<th>Assignee</th>
<td>polly-dev@googlegroups.com
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<th>Reporter</th>
<td>tobias@grosser.es
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</tr>
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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=15255" name="attach_15255" title="Test case">attachment 15255</a> <a href="attachment.cgi?id=15255&action=edit" title="Test case">[details]</a></span>
Test case
With <a href="https://llvm.org/svn/llvm-project/polly/trunk@252540">https://llvm.org/svn/llvm-project/polly/trunk@252540</a> 'polly-opt
-polly-scops -analyze expensive-boundary-context.ll' takes a very long time or
even aborts compilation. My current understanding is the assumptions we derive
are stored very efficiently as disjuncts, but when isl_set_complement is called
in Scop::buildBoundaryContext the set that is constructed becomes extremely
large. It might make sense to keep the boundary constraints as disjuncts and
directly generate a run-time check from these disjuncts.
This test case took about a day to be automatically reduced from one of the LNT
benchmarks currently failing. It is the result from me setting up bugpoint to
minimize a miscompile. During this reduction bugpoint run at some point in this
compile time problem and reduced this test case instead of the original
miscompile.</pre>
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