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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - LTO crashes with linker error on valid code at -O1 (also -Os and -O2) on x86_64-linux-gnu"
href="http://llvm.org/bugs/show_bug.cgi?id=19798">19798</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>LTO crashes with linker error on valid code at -O1 (also -Os and -O2) on x86_64-linux-gnu
</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 causes a linker error when it is compiled on
x86_64-linux-gnu by the current clang trunk using LTO at -O1 (also -Os and -O2)
in both 32-bit and 64-bit modes.
This is a regression from clang 3.4.
$ clang-trunk -v
clang version 3.5.0 (trunk 209103)
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 -O1 small.c; a.out
$ clang-trunk -flto -O0 small.c; a.out
$ clang-3.4 -flto -O1 small.c; a.out
$
$ clang-trunk -flto -O1 small.c
ld: /tmp/llvm/include/llvm/Support/Casting.h:237: typename llvm::cast_retty<X,
Y*>::ret_type llvm::cast(Y*) [with X = llvm::PHINode; Y = llvm::Instruction;
typename llvm::cast_retty<X, Y*>::ret_type = llvm::PHINode*]: Assertion
`isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
clang: error: unable to execute command: Aborted (core dumped)
clang: error: linker command failed due to signal (use -v to see invocation)
$
------------------------------
int a, c, d[2] = { 0, 1 }, e;
volatile int b;
int
main ()
{
for (; a < 1; a++)
for (; c < 1; c++)
{
if (d[1])
continue;
for (; e < 1; e++)
a && b;
}
return 0;
}</pre>
</div>
</p>
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