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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [OssFuzz Issue 26832] "No point in having a non-constant max backedge taken count!""
href="https://bugs.llvm.org/show_bug.cgi?id=48051">48051</a>
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<th>Summary</th>
<td>[OssFuzz Issue 26832] "No point in having a non-constant max backedge taken count!"
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<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
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>lebedev.ri@gmail.com, llvm-bugs@lists.llvm.org, nikita.ppv@gmail.com, spatel+llvm@rotateright.com
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<pre>Reduced from <a href="https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26832">https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=26832</a>
opt -irce
opt: /home/simon/LLVM/llvm-project/llvm/lib/Analysis/ScalarEvolution.cpp:7000:
llvm::ScalarEvolution::ExitLimit::ExitLimit(const llvm::SCEV*, const
llvm::SCEV*, bool, llvm::ArrayRef<const llvm::SmallPtrSetImpl<const
llvm::SCEVPredicate*>*>): Assertion `(isa<SCEVCouldNotCompute>(MaxNotTaken) ||
isa<SCEVConstant>(MaxNotTaken)) && "No point in having a non-constant max
backedge taken count!"' failed.
define void @scalar_after_vectorization_0() {
outer.ph:
br label %outer.body
outer.body: ; preds = %inner.end,
%outer.ph
%i = phi i64 [ 1, %outer.ph ], [ %i.next, %inner.end ]
%tmp0 = mul nuw nsw i64 %i, undef
br label %inner.body
inner.body: ; preds = %inner.body,
%outer.body
%j = phi i64 [ 1, %outer.body ], [ %tmp1, %inner.body ]
%tmp1 = add nuw nsw i64 %j, %tmp0
%B3 = mul i64 %tmp1, undef
%B13 = mul i64 %B3, 4294967296
%C2 = icmp slt i64 undef, %B13
br i1 %C2, label %inner.body, label %inner.end
inner.end: ; preds = %inner.body
%B4 = sub i64 9223372036854775807, -9223372036854775808
%B21 = and i64 %B4, %B4
%B9 = lshr i64 9223372036854775807, -1
%B16 = urem i64 %B4, %B9
%i.next = add i64 %i, %B16
%C = icmp ult i64 %B21, %i.next
br i1 %C, label %outer.body, label %outer.end
outer.end: ; preds = %inner.end
ret void
}</pre>
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