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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 - loop-reroll produces wrong code with "opt -jump-threading -prune-eh -loop-extract-single -prune-eh -instcombine -loop-rotate -inline -licm -loop-unroll -forceattrs -gvn -loop-reroll""
href="https://bugs.llvm.org/show_bug.cgi?id=42043">42043</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>loop-reroll produces wrong code with "opt -jump-threading -prune-eh -loop-extract-single -prune-eh -instcombine -loop-rotate -inline -licm -loop-unroll -forceattrs -gvn -loop-reroll"
</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=22026" name="attach_22026" title=".bc file of the source code">attachment 22026</a> <a href="attachment.cgi?id=22026&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
$gcc small.c -o small0.out && ./small0.out
9
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c
$clang small.bc -o small1.out && ./small1.out
9
$opt -jump-threading -prune-eh -loop-extract-single -prune-eh -instcombine
-loop-rotate -inline -licm -loop-unroll -forceattrs -gvn -loop-reroll small.bc
-o small-opt.bc
$clang small-opt.bc -o small2.out && ./small2.out
54
without loop-reroll pass, the output is correct.
$opt -jump-threading -prune-eh -loop-extract-single -prune-eh -instcombine
-loop-rotate -inline -licm -loop-unroll -forceattrs -gvn small.bc -o
small-opt1.bc
$clang small-opt1.bc -o small3.out && ./small3.out
9
------------------------------------------------
#include <stdio.h>
int a=0, b=0;
void c() {
unsigned short int d[9][6];
int e=0;
for (e = 0; e;)
;
for (a=0; a < 9; a++)
for (b = 0; b < 6; b++)
d[a][b] = 2;
}
void main() {
c();
printf("%d\n",a);
}</pre>
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