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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [JSC] It should be possible to always safely move GetByVal"
href="https://bugs.webkit.org/show_bug.cgi?id=157534">157534</a>
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<th>Summary</th>
<td>[JSC] It should be possible to always safely move GetByVal
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<th>Classification</th>
<td>Unclassified
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<th>Product</th>
<td>WebKit
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<th>Version</th>
<td>WebKit Nightly Build
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<th>Hardware</th>
<td>Unspecified
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<th>OS</th>
<td>Unspecified
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>JavaScriptCore
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>benjamin@webkit.org
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<pre>FTL had a but where GetByVal would be moved by Loop Invariant Code Motion invalidating assumption used to remove bounds checking (see <a class="bz_bug_link
bz_status_NEW "
title="NEW - [JSC] FTL can produce GetByVal nodes without proper bounds checking"
href="show_bug.cgi?id=157502">https://bugs.webkit.org/show_bug.cgi?id=157502</a>).
The fix was to move IntegerRange optimization after LICM to make sure the code is not moved after CheckInBounds is eliminated.
It would be better to have a deterministic way of knowing if a GetByVal can be moved and where it is safe to move it. For example, it should be explicitly illegal to hoist a GetByVal above its CheckInBounds.</pre>
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