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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [Coroutines] mem2reg causes "cannot move instruction since its users are not dominated by CoroBegin""
href="https://bugs.llvm.org/show_bug.cgi?id=36578">36578</a>
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<th>Summary</th>
<td>[Coroutines] mem2reg causes "cannot move instruction since its users are not dominated by CoroBegin"
</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>All
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Transformation Utilities
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>superjoe30@gmail.com
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</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=19988" name="attach_19988" title="repro.ll">attachment 19988</a> <a href="attachment.cgi?id=19988&action=edit" title="repro.ll">[details]</a></span>
repro.ll
In my frontend, I'm careful to store args that are referenced in the Cleanup
block into the coro frame, to avoid tripping "cannot move instruction since its
users are not dominated by CoroBegin":
define internal fastcc i8* @amain(%Allocator*, i16*) unnamed_addr #0 !dbg !234
{
store %Allocator* %0, %Allocator** %_anon3, align 8, !dbg !248
then later in the cleanup block:
%28 = load %Allocator*, %Allocator** %_anon3, align 8, !dbg !248
%29 = getelementptr inbounds %Allocator, %Allocator* %28, i32 0, i32 2, !dbg
!248
%30 = load void (%Allocator*, %"[]u8"*)*, void (%Allocator*, %"[]u8"*)** %29,
align 8, !dbg !248
%31 = call i8* @llvm.coro.free(token %6, i8* %12), !dbg !248
This works at -O0. But when mem2reg runs it replaces the load from _anon3 to %0
directly:
call fastcc void %31(%Allocator* nonnull %0, %"[]u8"* byval nonnull %2) #6,
!dbg !191
This trips the corosplit assertion.</pre>
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