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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - jump-threading makes the program suspend"
href="https://bugs.llvm.org/show_bug.cgi?id=41510">41510</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>jump-threading makes the program suspend
</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=21781" name="attach_21781" title=".bc file of the source code">attachment 21781</a> <a href="attachment.cgi?id=21781&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 355281)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm/build4/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/7.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.3.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
For the following code small.c, after running jump-threading pass, it will
suspend.
-----------------------------------------------------------
#include <stdio.h>
int a, b;
int main() {
c:
for (; a <= 1; a++) {
int d;
if (d)
goto c;
}
printf("%d\n",a);
}
-----------------------------------------------------------
$clang small.c -o small1.out && ./small1.out
2
$gcc small.c -o small2.out && ./small2.out
2
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c -o small.bc
$opt -mem2reg small.bc -o small-opt1.bc
$clang small-opt1.bc -o small3.out && timeout -s 9 120 ./small3.out
2
$opt -jump-threading small-opt1.bc -o small-opt2.bc
$clang small-opt2.bc -o small4.out && time -s 9 120 ./small4.out
Killed
The program cannot terminate even for a long time.</pre>
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