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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 segfault at -O2 in C mode, reduced test case included"
href="https://bugs.llvm.org/show_bug.cgi?id=49716">49716</a>
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<th>Summary</th>
<td>clang segfault at -O2 in C mode, reduced test case included
</td>
</tr>
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<th>Product</th>
<td>new-bugs
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>clang@evan.coeusgroup.com
</td>
</tr>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24690" name="attach_24690" title="Non-reduced, un-preprocessed source">attachment 24690</a> <a href="attachment.cgi?id=24690&action=edit" title="Non-reduced, un-preprocessed source">[details]</a></span>
Non-reduced, un-preprocessed source
Here is a reduced test case:
#include <stdlib.h>
typedef union {
int16_t i16 __attribute__((__vector_size__(32)));
int32_t i32 __attribute__((__vector_size__(32)));
} simde__m256i_private;
simde__m256i_private simde__m256i_to_private();
int simde_mm256_madd_epi16() {
simde__m256i_private r_, a_ = simde__m256i_to_private(),
b_ = simde__m256i_to_private();
for (size_t i = 0; i < sizeof sizeof(r_); i += 2)
r_.i32[i] = a_.i16[i] * b_.i16[i] + a_.i16[i + 1] * b_.i16[i + 1];
simde__m256i_from_private(r_);
}
Compile with -O2 using clang (clang++ works) on x86_64. Godbolt link:
<a href="https://godbolt.org/z/71o5hdY4h">https://godbolt.org/z/71o5hdY4h</a>
The problem only manifests in my codebase with clang 12, but this test case
seems to reliably reproduce the issue in earlier versions as well (back to 7 on
godbolt).
I'm also attaching the original (non-reduced) source. Please let me know if
you need any additional information.</pre>
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