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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wasm32: Regression with trivial bitcasts"
href="https://bugs.llvm.org/show_bug.cgi?id=38711">38711</a>
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<th>Summary</th>
<td>wasm32: Regression with trivial bitcasts
</td>
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<th>Product</th>
<td>libraries
</td>
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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>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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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
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<th>CC</th>
<td>dan433584@gmail.com, llvm-bugs@lists.llvm.org, sbc@chromium.org
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<p>
<div>
<pre>I'm a bit late to this diff but we're attempting to update LLVM in the Rust
repo [1] but the update is causing some of our wasm tests to fail. A bisection
of the failure points to this revision in LLVM -
<a href="https://reviews.llvm.org/D49517">https://reviews.llvm.org/D49517</a>.
I haven't put the time in yet to reduce this down to a standalone IR file as
I'm hoping those CC'd can help to see what's going on here. Taking one of our
failing test cases in rust-lang/rust I created a wasm file before and after the
change, yielding a diff that looks like --
<a href="https://gist.github.com/alexcrichton/9b8c71afa892cb89234a6b5ef2113028">https://gist.github.com/alexcrichton/9b8c71afa892cb89234a6b5ef2113028</a>.
It looks like a few shims were inserted (perhaps erroneously?) and the shim
inserted for the Vec/Deref looking symbol is the one which is causing the trap
(the `unreachable` instruction at the end)
Would y'all be able to help take a look to see what's going on here?
[1]: <a href="https://github.com/rust-lang/rust/pull/53611">https://github.com/rust-lang/rust/pull/53611</a></pre>
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