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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - opt cannot terminate with "opt -mem2reg -loop-unswitch -reg2mem -licm -structurizecfg -reg2mem -licm""
href="https://bugs.llvm.org/show_bug.cgi?id=40949">40949</a>
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<th>Summary</th>
<td>opt cannot terminate with "opt -mem2reg -loop-unswitch -reg2mem -licm -structurizecfg -reg2mem -licm"
</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>
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<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</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>
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=21558" name="attach_21558" title=".bc file of the source code">attachment 21558</a> <a href="attachment.cgi?id=21558&action=edit" title=".bc file of the source code">[details]</a></span>
.bc file of the source code
For this test case, opt cannot terminate. I have tested it using godbolt, and
the opt 6/7/truck versions all have this problem. The outputs of opt 6/7/truck
are as follows.
opt truck:
/compiler-explorer/c-preload/compiler-wrapper: line 21: 8512 Killed
"$@"
Compiler returned: 137
opt 7:
compiler-explorer/c-preload/compiler-wrapper: line 21: 13372 Killed
"$@"
Compiler returned: 137
opt 6:
/compiler-explorer/c-preload/compiler-wrapper: line 21: 18355 Killed
"$@"
Compiler returned: 137
The followings are my test environment and test steps.
$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
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c -o small.bc
$opt -mem2reg -loop-unswitch -reg2mem -licm -structurizecfg -reg2mem -licm
small.bc -o small-opt.bc
The following is the source code of small.c
#include "csmith.h"
a() {
int32_t b[8];
uint32_t c;
uint64_t d = 4073709551610;
for (;;) {
uint8_t e;
for (; 8;)
for (;; c++) {
if (b)
return 0;
if (d)
break;
}
}
}</pre>
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