<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Clang produces wrong code with -O1 (Combine redundant instructions on function)"
href="https://bugs.llvm.org/show_bug.cgi?id=46561">46561</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Clang produces wrong code with -O1 (Combine redundant instructions on function)
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</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>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>Vsevolod.Livinskij@frtk.ru
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>opt-bisect limit points to Combine redundant instructions on function
<span class="quote">>$ clang++ -w -O1 driver.cpp func.cpp && ./a.out </span >
42
<span class="quote">>$ clang++ -w -O0 driver.cpp func.cpp && ./a.out </span >
0
Reproducer:
Func.cpp
extern const bool tf_4_var_4;
extern const int tf_4_var_72;
extern unsigned long long int tf_4_var_124;
extern bool tf_4_array_3;
extern const bool tf_4_ptr_1;
void tf_4_foo() {
if (~(tf_4_var_72 ? tf_4_ptr_1 * tf_4_array_3 ^ ~tf_4_var_4 : 0))
tf_4_var_124 = 0;
}
Driver.cpp
#include <stdio.h>
#include "init.h"
const bool tf_4_var_4 = true;
const int tf_4_var_72 = 2085646722;
unsigned long long int tf_4_var_124 = 42;
bool tf_4_array_3 = false;
const bool tf_4_ptr_1 = true;
extern void tf_4_foo();
int main() {
tf_4_foo();
printf("%llu\n", tf_4_var_124);
return 0;
}
Init.h
extern const bool tf_4_var_4;
extern const int tf_4_var_72;
extern unsigned long long int tf_4_var_124;
extern bool tf_4_array_3;
extern const bool tf_4_ptr_1;
Clang version:
clang version 11.0.0 (<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
565e37c7702d181804c12d36b6010c513c9b3417)</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>