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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=18884">18884</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 at -Os and above
in 32-bit mode (but not 64-bit) on x86_64-linux-gnu.
This is a regression from 3.4.
$ clang-trunk -v
clang version 3.5 (trunk 201540)
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 multiilb: .;@m64
Candidate multiilb: 32;@m32
Selected multilib: .;@m64
$
$ clang-trunk -m32 -O1 small.c; a.out
0
$ clang-trunk -m64 -Os small.c; a.out
0
$ clang-3.4 -m32 -Os small.c; a.out
0
$
$ clang-trunk -m32 -Os small.c; a.out
1
$
-----------------------------------
int printf (const char *, ...);
int a, b, c, h, i, j;
#pragma pack(1)
struct
{
int:4;
int f2:23;
int f3:6;
int f4:31;
int f6:11;
} d[5] = {{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 0},
{0, 0, 0, 1}},
e, f, g;
static int
fn1 (int p)
{
int k;
for (;;)
{
k = e.f2 + d[4].f2;
f.f3 = k;
for (; h >= 0; h--)
for (;;)
{
for (; i; i++)
d[0] = d[4];
if (c)
{
j = a || 1 >> a ? 0 : b;
g.f3 = j ^ p;
break;
}
return 0;
}
}
}
int
main ()
{
fn1 (0);
fn1 (1);
printf ("%d\n", f.f3);
return 0;
}</pre>
</div>
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