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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Stack coloring fails to re-use stack that the inliner's alloca merging can recover"
href="https://llvm.org/bugs/show_bug.cgi?id=28821">28821</a>
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<th>Summary</th>
<td>Stack coloring fails to re-use stack that the inliner's alloca merging can recover
</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>Common Code Generator Code
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>chandlerc@gmail.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>If I turn off the Inliner's alloca merging (flag to be committed as
-disable-inlined-alloca-merging) I've found at least one function which
regresses stack size by a surprisingly large ratio (almost 3x) despite having
*identical instructions* before and after.
My only conclusion is that the allocas could have shared space but the stack
coloring algorithm failed to recognize this for some reason.
The function is "NArchive::N7z::GetStringForSizeValue(unsigned int)" in
7zHandler.cpp in the test-suite.</pre>
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</p>
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