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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Long live ranges of constants don't get rematerialized"
href="https://bugs.llvm.org/show_bug.cgi?id=43247">43247</a>
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<th>Summary</th>
<td>Long live ranges of constants don't get rematerialized
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<th>Product</th>
<td>libraries
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Register Allocator
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>aemerson@apple.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, quentin.colombet@gmail.com
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<p>
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<pre>We're enabling the localizer pass for optimizations in AArch64 GlobalISel,
which is a pass that tries to duplicate and move defs of constant-like
instructions close to their uses, so as to reduce the live ranges and register
pressure.
It would be good if the greedy register allocator could handle this problem for
us, but it seems to have been written with only SelectionDAG in mind which is
always block-local and doesn't have any notion of live range in its graph
representation.</pre>
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