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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wasm32: Failure to select what looks like a simd instruction?"
href="https://bugs.llvm.org/show_bug.cgi?id=39275">39275</a>
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<th>Summary</th>
<td>wasm32: Failure to select what looks like a simd instruction?
</td>
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<th>Product</th>
<td>libraries
</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>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: WebAssembly
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>alex@crichton.co
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, tlively@google.com
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<p>
<div>
<pre>I unfortunately haven't been able to reduce this much but compiling crates in
Rust with the `simd128` feature enabled causes a few to fail to compile. This
is presumably because with access to SIMD vectors LLVM will either
auto-vectorize or attempt to optimize loads/stores, but none of these crates
started with explicit SIMD (and the failures to codegen are limited to
optimized mode in Rust)
The first failure is this --
<a href="https://gist.github.com/alexcrichton/e902f1bd3ca5acc8a4b7c0902d5cb15c">https://gist.github.com/alexcrichton/e902f1bd3ca5acc8a4b7c0902d5cb15c</a> --
bytecode file. While `bugpoint` was able to reduce it the `bugpoint` reduction
looked a bit different than the original failure. I can try to reduce it more
though if that's helpful! (running `llc` over the file in that gist should
crash)
The second is this file --
<a href="https://gist.github.com/alexcrichton/d6d8556e11210ad02bc7348566c93826">https://gist.github.com/alexcrichton/d6d8556e11210ad02bc7348566c93826</a> -- which
looks similar to the first. This time `llc` requires the `-thread-model=single`
and `-wasm-enable-unimplemented-simd` flags to reproduce</pre>
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