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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 (-O0 is correct)"
href="https://bugs.llvm.org/show_bug.cgi?id=46029">46029</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>inconsistent behaviors at -O3 (-O0 is correct)
</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>
<pre>Created <span class=""><a href="attachment.cgi?id=23515" name="attach_23515" title="the binary">attachment 23515</a> <a href="attachment.cgi?id=23515&action=edit" title="the binary">[details]</a></span>
the binary
$ 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 -g -O3 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`foo + 214 at small.c:11:7, address =
0x0000000000401206
(lldb) r
Process 295458 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 295458 exited with status = 0 (0x00000000)
(lldb) q
/************************************
As showed, when setting breakpoint on Line 11, lldb exit directly.
However, when step-i, Line 11 is hit by lldb as follow:
************************************/
$ 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:15:3, address =
0x00000000004013b1
(lldb) r
Process 295500 launched: '/home/yibiao/Debugger/a.out' (x86_64)
Process 295500 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004013b1 a.out`main at small.c:15:3
12 }
13
14 int main() {
-> 15 foo(2, 0);
16 return 0;
17 }
18
(lldb) si -c 19
Process 295500 stopped
* thread #1, name = 'a.out', stop reason = instruction step into
frame #0: 0x000000000040135e a.out`foo(r=4210760, n=0) at small.c:11:14
8
9 while(i-->0)
10 if(n==0 || c[r+i]==0)
-> 11 g[r+i] = 0;
12 }
13
14 int main() {
(lldb)
$ cat small.c
int g[10], c[10];
__attribute__ ((noinline))
void foo(int r, int n) {
int i=0;
if(r>g[r])
i=r;
while(i-->0)
if(n==0 || c[r+i]==0)
g[r+i] = 0;
}
int main() {
foo(2, 0);
return 0;
}</pre>
</div>
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