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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - loop-unswitch makes function broken with "opt -instcombine -lowerswitch -loop-rotate -jump-threading -lcssa -loop-unswitch""
href="https://bugs.llvm.org/show_bug.cgi?id=42448">42448</a>
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<th>Summary</th>
<td>loop-unswitch makes function broken with "opt -instcombine -lowerswitch -loop-rotate -jump-threading -lcssa -loop-unswitch"
</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>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>cszide@163.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22165" name="attach_22165" title=".bc file of the source code">attachment 22165</a> <a href="attachment.cgi?id=22165&action=edit" title=".bc file of the source code">[details]</a></span>
.bc file of the source code
$clang -v
clang version 9.0.0 (trunk 363125)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build1/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$clang -O3 -c -emit-llvm -femit-all-decls -mllvm -disable-llvm-optzns small.c
$opt -instcombine -lowerswitch -loop-rotate -jump-threading -lcssa
-loop-unswitch small.bc -o small-opt.bc
PHI nodes must have at least one entry. If the block is dead, the PHI should
be removed!
%storemerge = phi i32
in function e
LLVM ERROR: Broken function found, compilation aborted!
--------------------------------------------------
long a, b, d;
int c;
void e() {
f:
for (;;) {
int g;
b = 0;
for (; b <= 4;) {
c = 1;
for (; c;)
goto f;
for (; a;)
for (; d;)
;
}
}
}</pre>
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