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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=43893">43893</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Wrong debug info generated at -O2 (-O0 is correct)
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>qrzhang@gatech.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
</td>
</tr></table>
<p>
<div>
<pre>The expected output from lldb should be -1. However, compiled with "-O2", lldb
outputs -8.
$ clang-trunk -v
clang version 10.0.0 (trunk 375507)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
$ clang-trunk -g abc.c -O2
$ lldb-trunk -s cmds -batch a.out
(lldb) b 5
Breakpoint 1: where = a.out`main + 7 at abc.c:6:1, address = 0x0000000000400487
(lldb) r
Process 12592 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000400487 a.out`main at abc.c:6:1
3 int b = --a, l_1240 = -8L;
4 l_1240 = b;
5 b > 0; // optimize_me_not
-> 6 }
Process 12592 launched: '/home/absozero/projects/LLDB-testing/reduce/a.out'
(x86_64)
(lldb) p l_1240
(int) $0 = -8
$ clang-trunk -g abc.c
$ lldb-trunk -s cmds -batch a.out
(lldb) b 5
Breakpoint 1: where = a.out`main + 42 at abc.c:6:1, address =
0x00000000004004aa
(lldb) r
Process 12562 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004004aa a.out`main at abc.c:6:1
3 int b = --a, l_1240 = -8L;
4 l_1240 = b;
5 b > 0; // optimize_me_not
-> 6 }
Process 12562 launched: '/home/absozero/projects/LLDB-testing/reduce/a.out'
(x86_64)
(lldb) p l_1240
(int) $0 = -1
$ cat abc.c
char a;
int main() {
int b = --a, l_1240 = -8;
l_1240 = b;
b > 0; // optimize_me_not
}
$ cat cmds
b 5
r
p l_1240
kill
q</pre>
</div>
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