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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang miscompiles with "-newgvn" at -O2 on valid code"
href="https://bugs.llvm.org/show_bug.cgi?id=39057">39057</a>
</td>
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<th>Summary</th>
<td>clang miscompiles with "-newgvn" at -O2 on valid code
</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>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</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>helloqirun@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
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<pre>It's maybe a dup of <a class="bz_bug_link
bz_status_NEW "
title="NEW - clang miscompiles with "-newgvn" at -O2 on valid code"
href="show_bug.cgi?id=39056">bug 39056</a>. Bisect points to different revisions though.
clang-r342369: first working build
clang-r342387: next failing build
$ clang-trunk -v
clang version 8.0.0 (trunk 342833)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
$ clang-trunk abc.c ; ./a.out
0
0
2
0
0
0
$ clang-trunk -mllvm -enable-newgvn -O2 abc.c ; ./a.out
0
0
0
0
0
0
$ cat abc.c
int printf(const char *, ...);
volatile int a, d, f;
short b;
char c[6][1];
char e;
void h() {
int g = 67;
for (; d <= 1; d++) {
b ^= 2;
e = g >= 32 || b > 5 >> g ? b : g;
c[2][0] = e;
a;
g = 0;
for (; g <= 1; g++)
;
}
}
int main() {
h();
for (; f < 6; f++)
printf("%d\n", c[f][0]);
}</pre>
</div>
</p>
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