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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 - inconsistent behaviors at -O3"
href="https://bugs.llvm.org/show_bug.cgi?id=46047">46047</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>inconsistent behaviors at -O3
</td>
</tr>
<tr>
<th>Product</th>
<td>lldb
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>lldb-dev@lists.llvm.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>yangyibiao@hust.edu.cn
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - inconsistent behaviors at -O3"
href="https://bugs.llvm.org/show_bug.cgi?id=46047#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - inconsistent behaviors at -O3"
href="https://bugs.llvm.org/show_bug.cgi?id=46047">bug 46047</a>
from <span class="vcard"><a class="email" href="mailto:yangyibiao@hust.edu.cn" title="Yibiao Yang (杨已彪) <yangyibiao@hust.edu.cn>"> <span class="fn">Yibiao Yang (杨已彪)</span></a>
</span></b>
<pre>Created <span class=""><a href="attachment.cgi?id=23535" name="attach_23535" title="the binary">attachment 23535</a> <a href="attachment.cgi?id=23535&action=edit" title="the binary">[details]</a></span>
the binary</pre>
</div>
<div>
<pre>$ clang --version
clang version 11.0.0 (/home/yibiao/.cache/yay/llvm-git/llvm-project
871beba234a83a2a02da9dedbd59b91a1bfbd7af)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ lldb --version
lldb version 11.0.0
clang revision 871beba234a83a2a02da9dedbd59b91a1bfbd7af
llvm revision 871beba234a83a2a02da9dedbd59b91a1bfbd7af
$ clang -O3 -g small.c
$ lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) b 11
Breakpoint 1: where = a.out`main + 79 at small.c:11:3, address =
0x000000000040117f
(lldb) r
Process 565482 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 565482 exited with status = 0 (0x00000000)
(lldb)
/****************************************
As showed above, Line 11 is not hit by LLDB when setting breakpoint at Line 11.
However, Line 11 is hit by LLDB when using step-i.
****************************************/
$ lldb a.out
(lldb) target create "a.out"
Current executable set to '/home/yibiao/Debugger/a.out' (x86_64).
(lldb) b main
Breakpoint 1: where = a.out`main + 1 at small.c:6:10, address =
0x0000000000401131
(lldb) r
Process 565440 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 565440 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000401131 a.out`main at small.c:6:10
3
4 int main() {
5 for (int e=0; e<10; e++)
-> 6 d[e] = 1;
7 if (d[0])
8 c = a = (b == 0 || 1 % b);
9 if (a != 1)
(lldb) si -c 10
Process 565440 stopped
* thread #1, name = 'a.out', stop reason = instruction step into
frame #0: 0x0000000000401197 a.out`main at small.c:11:3
8 c = a = (b == 0 || 1 % b);
9 if (a != 1)
10 abort();
-> 11 return 0;
12 }
(lldb)
$ cat small.c
#include <stdlib.h>
int a, b, c, d[10];
int main() {
for (int e=0; e<10; e++)
d[e] = 1;
if (d[0])
c = a = (b == 0 || 1 % b);
if (a != 1)
abort();
return 0;
}</pre>
</div>
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