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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Assertion failure in AArch64 backend: "Detected cycle in SelectionDAG""
href="https://bugs.llvm.org/show_bug.cgi?id=43056">43056</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Assertion failure in AArch64 backend: "Detected cycle in SelectionDAG"
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Backend: AArch64
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>tstellar@redhat.com
</td>
</tr>
<tr>
<th>CC</th>
<td>arnaud.degrandmaison@arm.com, llvm-bugs@lists.llvm.org, peter.smith@linaro.org, Ties.Stuij@arm.com
</td>
</tr>
<tr>
<th>Blocks</th>
<td>42474
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22397" name="attach_22397" title="Original Test Case">attachment 22397</a> <a href="attachment.cgi?id=22397&action=edit" title="Original Test Case">[details]</a></span>
Original Test Case
Reproduce with:
llc -march=aarch64 -mcpu=thunderxt88 < aarch64-sdag-cycle-reduced.ll
Full error message:
Detected cycle in SelectionDAG
Offending node:
t659: v4f32,i64,ch = AArch64ISD::LD1DUPpost<(load 4 from %ir.96)> t489, t460,
t120
t460: i64,ch = load<(load 8 from %ir."&context.constants_ptr[]7")> t456, t2,
undef:i64
t2: i64,ch = CopyFromReg t0, Register:i64 %7
t1: i64 = Register %7
t11: i64 = undef
t120: i64 = shl t118, Constant:i64<2>
t118: i64 = sign_extend t117
t117: i32 = extract_vector_elt t589, Constant:i64<0>
t589: v4i32 = and t584, t587
t584: v4i32 = AArch64ISD::VSHL t407, Constant:i32<2>
t407: v4i32 = add t582, t655
t582: v4i32 = AArch64ISD::VSHL t96, Constant:i32<1>
t96: v4i32 = bitcast t659
t659: v4f32,i64,ch = AArch64ISD::LD1DUPpost<(load 4 from
%ir.96)> t489, t460, t120
t124: i32 = Constant<1>
t655: v4i32 = AArch64ISD::MOVIshift Constant:i32<3>,
Constant:i32<0>
t106: i32 = Constant<3>
t19: i32 = Constant<0>
t97: i32 = Constant<2>
t587: v4i32 = xor t583, t586
t583: v4i32 = AArch64ISD::CMHS t407, t647
t407: v4i32 = add t582, t655
t582: v4i32 = AArch64ISD::VSHL t96, Constant:i32<1>
t96: v4i32 = bitcast t659
t124: i32 = Constant<1>
t655: v4i32 = AArch64ISD::MOVIshift Constant:i32<3>,
Constant:i32<0>
t106: i32 = Constant<3>
t19: i32 = Constant<0>
t647: v4i32 = AArch64ISD::DUP t457
t457: i32,ch = load<(load 4 from %ir.95)> t456, t73, undef:i64
t73: i64 = add t2, Constant:i64<128>
t11: i64 = undef
t586: v4i32 = BUILD_VECTOR Constant:i32<-1>, Constant:i32<-1>,
Constant:i32<-1>, Constant:i32<-1>
t585: i32 = Constant<-1>
t585: i32 = Constant<-1>
t585: i32 = Constant<-1>
t585: i32 = Constant<-1>
t10: i64 = Constant<0>
t119: i64 = Constant<2></pre>
</div>
</p>
<div id="referenced">
<hr style="border: 1px dashed #969696">
<b>Referenced Bugs:</b>
<ul>
<li>
[<a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED - [meta] 9.0.0 Release Blockers"
href="https://bugs.llvm.org/show_bug.cgi?id=42474">Bug 42474</a>] [meta] 9.0.0 Release Blockers
</li>
</ul>
</div>
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