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List: llvm-bugs
Subject: [LLVMbugs] [Bug 16184] New: incorrect code for loop at -O3 in 32-bit mode
From: bugzilla-daemon () llvm ! org
Date: 2013-05-30 18:13:18
Message-ID: bug-16184-206 () http ! llvm ! org/bugs/
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--1369937598.eB2DFe411.10979
Date: Thu, 30 May 2013 13:13:18 -0500
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http://llvm.org/bugs/show_bug.cgi?id=16184
Bug ID: 16184
Summary: incorrect code for loop at -O3 in 32-bit mode
Product: clang
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: LLVM Codegen
Assignee: unassignedclangbugs@nondot.org
Reporter: dhazeghi@yahoo.com
CC: llvmbugs@cs.uiuc.edu
Classification: Unclassified
The following testcase is miscompiled on x86_64-linux when built at -O3 in
32-bit mode with current clang trunk. This is a regression from clang 3.2
which handled this code correctly.
$ clang-trunk -v
clang version 3.4 (trunk 182920)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang-trunk -O2 -m32 wrong.c
$ ./a.out
0
$ clang-3.2 -O3 -m32 wrong.c
$ ./a.out
0
$ clang-trunk -O3 -m32 wrong.c
$ ./a.out
4
$
-------------------------
int printf(const char *, ...);
int a, b, c, e, f;
static int *d = &c;
static void f1 ( int *p ) {
int i;
for ( ; b <= 3; b++ ) {
*p = 8;
i = a || 1 < -a ? 1 : 0;
*d = i | e && *p;
}
}
int main ( ) {
f1 ( &f );
printf ( "%d\n", c );
return 0;
}
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--1369937598.eB2DFe411.10979
Date: Thu, 30 May 2013 13:13:18 -0500
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<html>
<head>
<base href="http://llvm.org/bugs/" />
</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 --- - incorrect code for loop at -O3 in 32-bit mode"
href="http://llvm.org/bugs/show_bug.cgi?id=16184">16184</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>incorrect code for loop at -O3 in 32-bit mode
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</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>normal
</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>dhazeghi@yahoo.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following testcase is miscompiled on x86_64-linux when built at -O3 in
32-bit mode with current clang trunk. This is a regression from clang 3.2
which handled this code correctly.
$ clang-trunk -v
clang version 3.4 (trunk 182920)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang-trunk -O2 -m32 wrong.c
$ ./a.out
0
$ clang-3.2 -O3 -m32 wrong.c
$ ./a.out
0
$ clang-trunk -O3 -m32 wrong.c
$ ./a.out
4
$
-------------------------
int printf(const char *, ...);
int a, b, c, e, f;
static int *d = &c;
static void f1 ( int *p ) {
int i;
for ( ; b <= 3; b++ ) {
*p = 8;
i = a || 1 < -a ? 1 : 0;
*d = i | e && *p;
}
}
int main ( ) {
f1 ( &f );
printf ( "%d\n", c );
return 0;
}</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>
--1369937598.eB2DFe411.10979--
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