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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 from loop with FP"
href="http://llvm.org/bugs/show_bug.cgi?id=21409">21409</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code from loop with FP
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</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>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>regehr@cs.utah.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 program counts the number of floats between 0.56 and 0.57. I
believe it is conforming.
johnregehrs-MacBook-Air:~ regehr$ clang -v
clang version 3.6.0 (trunk 220780)
Target: x86_64-apple-darwin14.0.0
Thread model: posix
johnregehrs-MacBook-Air:~ regehr$ clang fp.c ; ./a.out
167773
johnregehrs-MacBook-Air:~ regehr$ clang -O fp.c ; ./a.out
0
johnregehrs-MacBook-Air:~ regehr$ cat fp.c
#include <assert.h>
#include <string.h>
#include <stdio.h>
int main (void) {
unsigned d=0;
int c=0;
while (1) {
float f;
memcpy(&f, &d, 4);
if (f>=0.56 && f<=0.57)
c++;
d++;
if (d==0)
break;
}
printf ("%d\n", c);
return 0;
}
johnregehrs-MacBook-Air:~ regehr$</pre>
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