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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [SCEV] Violation of proposed definitional flag rules"
href="https://bugs.llvm.org/show_bug.cgi?id=51817">51817</a>
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<th>Summary</th>
<td>[SCEV] Violation of proposed definitional flag rules
</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>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>listmail@philipreames.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>This bug exists to track known violations of the proposed nowrap flag semantics
for SCEV in <a href="https://reviews.llvm.org/D109553">https://reviews.llvm.org/D109553</a>. If that proposal is accepted,
this becomes a punch list. If it isn't, it will be closed as invalid.
Issues known at time of filing
* When folding loop invariant terms into an AddRec's start (in getAddExpr), we
propagate flag valid in the defining scope of the AddRec outside of it. This
is D106852.
* In applyLoopGuards, we apply contextual flags when reasoning about the
replacement given a urem expression. Removing this causes no test diffs.
* In getGEPExpr, we blindly copy flags from the IR gep (if inbounds) to the
corresponding MulExprs and AddExpr. This creates a set of SCEVs with
non-definitional flags. As noted in the fixme, we should be using similar
logic to AddRecNeverPoison here.</pre>
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