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<base href="http://llvm.org/bugs/" />
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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 --- - wrong code at -Os and above on x86_64-linux-gnu in 32-bit mode"
href="http://llvm.org/bugs/show_bug.cgi?id=21295">21295</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -Os and above on x86_64-linux-gnu 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>All
</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>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>su@cs.ucdavis.edu
</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 code is miscompiled by the current clang trunk (as well as 3.3
and later) on x86_64-linux-gnu at -Os and above in 32-bit mode (but not in
64-bit mode).
This is a regression from 3.2.
$ clang-trunk -v
clang version 3.6.0 (trunk 219779)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.8.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.1
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
$
$ clang-trunk -m32 -O1 small.c; a.out
-1
$ clang-trunk -m64 -Os small.c; a.out
-1
$ clang-3.2 -m32 -Os small.c; a.out
-1
$
$ clang-trunk -m32 -Os small.c; a.out
-12
$ clang-3.5.0 -m32 -Os small.c; a.out
-12
$ clang-3.4.2 -m32 -Os small.c; a.out
1
$ clang-3.4.1 -m32 -Os small.c; a.out
1
$ clang-3.4 -m32 -Os small.c; a.out
1
$ clang-3.3 -m32 -Os small.c; a.out
1
$
---------------------------------
int printf (const char *, ...);
struct S0
{
char f2;
int f3;
char f4;
char f5;
int f7;
int f8;
};
struct S1
{
struct S0 f1;
struct S0 f4;
};
struct S3
{
struct S1 f4;
struct S0 f5;
} a, b;
struct S3
fn1 (struct S3 p)
{
struct S1 c = { {0, 0, 0, 0, 0, 0}, {-1, 0, 0, 0, 0, 0} };
if (a.f5.f4)
p.f4 = a.f4;
else
p.f4.f1 = c.f4;
return p;
}
int
main ()
{
struct S3 d = { {{0, 0, 0, 0, 0, 0}, {0, 0, -1, 1, 0, 0}}, {0, 0, 0, 0, 0, 0}
};
b = fn1 (d);
printf ("%d\n", b.f4.f1.f2);
return 0;
}</pre>
</div>
</p>
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