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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong debug info generated at -O2 (-O0 is correct)"
href="https://bugs.llvm.org/show_bug.cgi?id=40857">40857</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Wrong debug info generated at -O2 (-O0 is correct)
</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>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Keywords</th>
<td>wrong-debug
</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>davide@freebsd.org
</td>
</tr>
<tr>
<th>CC</th>
<td>aprantl@apple.com, cmtice@google.com, david.stenberg@ericsson.com, dblaikie@gmail.com, echristo@gmail.com, florian_hahn@apple.com, jeremy.morse.llvm@gmail.com, llvm-bugs@lists.llvm.org, vsk@apple.com
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<p>
<div>
<pre>$ cat outer.c
void optimize_me_not() {}
$ cat 7.c
int a[6];
int b;
int main() {
int i, c = 8;
for (; c; c--)
b = b >> 5;
i = 0;
for (; i < 7; i++)
for (; c < 2; c++)
b = b & 4095 ^ a[b & 255];
i = 0;
for (; i < 5; i++)
;
b = b >> 8 ^ 5;
optimize_me_not();
}
### -O2
(lldb) r
Process 16600 launched: '/home/davide/finished_reducing/a.out' (x86_64)
Process 16600 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004004be a.out`main at 7.c:15:3
12 for (; i < 5; i++)
13 ;
14 b = b >> 8 ^ 5;
-> 15 optimize_me_not();
16 }
(lldb) frame var
(int) c = 0
(int) i = 0
### -O0
Process 18140 launched: '/home/davide/finished_reducing/a.out' (x86_64)
Process 18140 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000400562 a.out`main at 7.c:15:3
12 for (; i < 5; i++)
13 ;
14 b = b >> 8 ^ 5;
-> 15 optimize_me_not();
16 }
(lldb) frame var
(int) i = 5
(int) c = 2</pre>
</div>
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