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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 - gvn-hoist produces wrong code with "opt -sroa -loop-unswitch -loop-rotate -sccp -jump-threading -gvn-hoist""
href="https://bugs.llvm.org/show_bug.cgi?id=42283">42283</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>gvn-hoist produces wrong code with "opt -sroa -loop-unswitch -loop-rotate -sccp -jump-threading -gvn-hoist"
</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=22103" name="attach_22103" title=".bc file of the source code">attachment 22103</a> <a href="attachment.cgi?id=22103&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 362492)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm2/build/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 small.c -o small1.out && ./small1.out
28
$ gcc small.c -o small2.out && ./small2.out
28
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c
$opt -sroa -loop-unswitch -loop-rotate -sccp -jump-threading -gvn-hoist
small.bc -o small-opt.bc
$clang small-opt.bc -o small3.out && ./small3.out
0
------------------------------------------
#include<stdio.h>
unsigned a;
char b;
int c, d;
int main(int argc, char *argv[]) {
int e, f = 0;
if (argc == 0)
f = 1;
for (e = 0; e < 2; e++)
for (; c; c++) {
for (d; d; d++) {
printf("%d%d\n", b, a ^ 5);
if (f)
;
}
}
for (e = 0; e < 1; e++) {
a = a ^ a ^ 40;
a;
if (f)
;
printf("%X\n", a);
}
return 0;
}</pre>
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