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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 --- - SIGFPE generated for looping code at -O3"
href="http://llvm.org/bugs/show_bug.cgi?id=16041">16041</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>SIGFPE generated for looping code at -O3
</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 by current clang trunk on
x86_64-unknown-linux-gnu at -O3 optimization level, crashing with a floating
point exception.
$ clang-trunk -v
clang version 3.4 (trunk 181995)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ mv try2.c crash.c
$ clang-trunk -v
clang version 3.4 (trunk 181995)
Target: x86_64-pc-linux-gnu
Thread model: posix
$ clang-trunk -O2 crash.c
$ ./a.out
$ clang-trunk -O3 crash.c
$ ./a.out
Floating point exception (core dumped)
-------------------------------------------
short s;
int a;
int b, c;
volatile int v;
static int u[] = { 0, 0, 0, 0, 0, 1 };
void foo() {
int i, j;
for (; b <= 0; ++b) {
int k, d = 0;
for (; d <= 5; d++) {
int *l = &c;
int e = 0;
for (; e <= 0; e++) {
int *m = &k;
unsigned int n = u[d];
i = !a ? n : n / a;
j = s ? 0 : (1 >> v);
*m = j;
}
*l = k < i;
}
}
}
int main() {
foo();
return 0;
}</pre>
</div>
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