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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 - Variable's value not available after assignment at Oz after SROA"
href="https://bugs.llvm.org/show_bug.cgi?id=52237">52237</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Variable's value not available after assignment at Oz after SROA
</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>DebugInfo
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>cristianassaiante@outlook.com
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, keith.walker@arm.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
</td>
</tr></table>
<p>
<div>
<pre>Variable l_201 value is not available after the first loop iteration on lines 4
and 5. It is only available on line 6.
>From bisect, this behavior may be caused by SROA on function (b).
$ cat a.c
short a;
void b() {
char l_201 ;
for (;
a <= 8;
++a) l_201 = 0;
}
int main () {
{
b();
}
}
$ clang -v
clang version 13.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
$ lldb -v
lldb version 13.0.0
$ clang -g -Oz -o opt a.c
$ lldb opt
(lldb) target create "opt"
Current executable set to '/home/stepping/7/reduce/opt' (x86_64).
(lldb) b 4
Breakpoint 1: where = opt`b + 11 at a.c:4:9, address = 0x0000000000400483
(lldb) run
Process 112 launched: '/home/stepping/7/reduce/opt' (x86_64)
Process 112 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000400483 opt`b at a.c:4:9
1 short a;
2 void b() {
3 char l_201 ;
-> 4 for (;
5 a <= 8;
6 ++a) l_201 = 0;
7 }
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x0000000000400485 opt`b at a.c:6:3
3 char l_201 ;
4 for (;
5 a <= 8;
-> 6 ++a) l_201 = 0;
7 }
8 int main () {
9 {
(lldb) frame var
(char) l_201 = '\0'
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x000000000040047f opt`b at a.c:5:5
2 void b() {
3 char l_201 ;
4 for (;
-> 5 a <= 8;
6 ++a) l_201 = 0;
7 }
8 int main () {
(lldb) frame var
(char) l_201 = <variable not available>
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = breakpoint 1.1
frame #0: 0x0000000000400483 opt`b at a.c:4:9
1 short a;
2 void b() {
3 char l_201 ;
-> 4 for (;
5 a <= 8;
6 ++a) l_201 = 0;
7 }
(lldb) n
Process 112 stopped
* thread #1, name = 'opt', stop reason = step over
frame #0: 0x0000000000400485 opt`b at a.c:6:3
3 char l_201 ;
4 for (;
5 a <= 8;
-> 6 ++a) l_201 = 0;
7 }
8 int main () {
9 {
(lldb) frame var
(char) l_201 = '\0'</pre>
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