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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Instcombine hangs with "opt -functionattrs -disable-basicaa -O1""
href="https://bugs.llvm.org/show_bug.cgi?id=44541">44541</a>
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<th>Summary</th>
<td>Instcombine hangs with "opt -functionattrs -disable-basicaa -O1"
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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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
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<th>Component</th>
<td>new bugs
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>mikael.holmen@ericsson.com
</td>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<pre>Created <span class=""><a href="attachment.cgi?id=23015" name="attach_23015" title="bbi-37458_x86.ll reproducer">attachment 23015</a> <a href="attachment.cgi?id=23015&action=edit" title="bbi-37458_x86.ll reproducer">[details]</a></span>
bbi-37458_x86.ll reproducer
Running
opt -functionattrs -disable-basicaa -O1 -S -o - ./bbi-37458_x86.ll
seems to hang forever.
Adding -debug-pass=Executions shows
[2020-01-14 15:08:50.872376271] 0x611e690 Executing Pass 'Combine
redundant instructions' on Function 'test_sub3_4'...
and adding -debug gives repeated occurences of
IC: Visiting: %_tmp2687 = select i1 %1808, i16 0, i16 %_tmp2685
IC: Visiting: %1808 = icmp sgt i16 0, %_tmp2685
IC: Mod = %1808 = icmp sgt i16 0, %_tmp2685
New = %1808 = icmp slt i16 %_tmp2682, 0
IC: ADD: %_tmp2687 = select i1 %1808, i16 0, i16 %_tmp2685
IC: ADD: %1808 = icmp slt i16 %_tmp2682, 0
IC: Visiting: %1808 = icmp slt i16 %_tmp2682, 0
IC: Visiting: %_tmp2687 = select i1 %1808, i16 0, i16 %_tmp2685
I've tried to reduce the command line to some minor variation of just
opt -instcombine
but I can't seem to manage that. :/
The problem seems to be fairly old, I've seen it in builds from around late
March 2019.</pre>
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