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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - loop-idiom miscompile with restrict and unwinding"
href="https://llvm.org/bugs/show_bug.cgi?id=27859">27859</a>
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<tr>
<th>Summary</th>
<td>loop-idiom miscompile with restrict and unwinding
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Windows NT
</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>Loop Optimizer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>eli.friedman@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Testcase:
#include <cstdlib>
void f() { throw 1; }
void (*ff)() = f;
void g(char* __restrict base, unsigned size) {
for (unsigned i = 0; i < size; ++i) {
ff();
base[i] = 0;
}
}
void (*gg)(char*__restrict,unsigned) = g;
int main() {
char a[8] = {1};
try {
gg(a, 8);
} catch (...) {
if (a[0] != 1) abort();
}
}
Works with gcc and clang -O0, aborts with clang -O2.
There's a missing safety check in LoopIdiomRecognize.
(Artificial testcase.)</pre>
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