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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - wasm64: Crash with register use before def"
href="https://bugs.llvm.org/show_bug.cgi?id=52352">52352</a>
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<th>Summary</th>
<td>wasm64: Crash with register use before def
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: WebAssembly
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>alex@crichton.co
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=25399" name="attach_25399" title="bugpoint-reduced IR">attachment 25399</a> <a href="attachment.cgi?id=25399&action=edit" title="bugpoint-reduced IR">[details]</a></span>
bugpoint-reduced IR
I apologize in advance for the bad title here. In an effort to test out Rust on
the wasm64 backend I was curious to test out the performance of a
wasm32-vs-wasm64 program and the first thing I was going to test was a wasm
program that itself implements a wasm text parser. In compiling this program
though (Rust source code) I got a crash in LLVM:
llc:
/home/acrichto/code/rust/src/llvm-project/llvm/lib/CodeGen/MachineLoopInfo.cpp:199:
bool llvm::MachineLoop::isLoopInvariant(llvm::MachineInstr&) const: Assertion
`MRI->getVRegDef(Reg) && "Machine instr not mapped for this vreg?!"' failed.
Using bugpoint on the suspect LLVM module I was able to reduce the original
test case but it unfortunately gives a different crash now:
llc:
/home/acrichto/code/rust/src/llvm-project/llvm/lib/CodeGen/LiveVariables.cpp:129:
void llvm::LiveVariables::HandleVirtRegUse(llvm::Register,
llvm::MachineBasicBlock*, llvm::MachineInstr&): Assertion `MRI->getVRegDef(Reg)
&& "Register use before def!"' failed.
In any case this seemed like a good point to open up a bug. I've attached both
the un-minimized module as well as the bugpoint-reduced module here in case
fixing the bugpoint issue is distinct from the original issue.</pre>
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