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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 --- - may wrong code bug at -O0 level"
href="http://llvm.org/bugs/show_bug.cgi?id=17990">17990</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>may wrong code bug at -O0 level
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.3
</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>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>justmao945@gmail.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>Created <span class=""><a href="attachment.cgi?id=11567" name="attach_11567" title="source">attachment 11567</a> <a href="attachment.cgi?id=11567&action=edit" title="source">[details]</a></span>
source
Sorry for I don't know where to post this bug, so I put it here as the "NEW".
Thanks.
Source code:
------------------------------------------
#include <ctype.h>
#include <stdio.h>
int main() {
const char* str = "abcd1234abcd12333";
for(size_t i = 0; i < 10; ++i) {
char c = str[i];
bool d = isdigit(c); // Clang store str[0] to d, volatile doesn't help
if(i < 10 && d == isdigit(str[i]) ) {
printf("%zu %c\n", i, str[i]);
}
}
return 0;
}
------------------------------------------
Compilation and run
------------------------------------------
ohio:tmp$clang -O0 bug.cc
ohio:tmp$./a.out
0 a
1 b
2 c
3 d
8 a
9 b
ohio:tmp$clang -O1 bug.cc
ohio:tmp$./a.out
0 a
1 b
2 c
3 d
4 1
5 2
6 3
7 4
8 a
9 b</pre>
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