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<base href="https://bugs.llvm.org/">
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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 at -Os on x86_64-linux-gnu"
href="https://bugs.llvm.org/show_bug.cgi?id=52485">52485</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>wrong code at -Os on x86_64-linux-gnu
</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>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>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>haoxintu@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
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<pre>Hi all.
This seems to be a recent regression issue on the current trunk version of
clang.
$cat small.c
#include <stdint.h>
#include <stdio.h>
int32_t a;
int32_t b[10][1][9];
uint8_t c(int32_t *, uint64_t, uint32_t, int32_t d, int32_t *) { return d; }
int main() {
int e = 0, f=0, g=0;
int32_t *h = &b[0][0][3];
for (a = -23; a != -15; a = a + 2) {
int32_t *i = &b[0][0][3];
*i =
c(h, a, 0, b[0][0][3], &b[3][0][2]) ^ (-9L+0);
}
for (e = f = g = 0; g < 9; g++){
if (g == 3)
printf("%d\n", b[e][f][g]);
}
}
$clang -w -O1 small.c ; ./a.out
-256
$clang -w -Os small.c ; ./a.out
0
$clang-13 -w -Os small.c ; ./a.out
-256
$clang -v
clang version 14.0.0 (<a href="https://github.com/llvm/llvm-project">https://github.com/llvm/llvm-project</a>
ed7b37155b48715dc5b2ec8c52571ce754cf7a80)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/haoxin/haoxin-data/compilers/llvm-project/build/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/9
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/9
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
On godbolt: <a href="https://godbolt.org/z/K5TvqTxj3">https://godbolt.org/z/K5TvqTxj3</a>
Thanks,
Haoxin</pre>
</div>
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