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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 - Severe optimizer regression with LLVM 11.0.0-rc2"
href="https://bugs.llvm.org/show_bug.cgi?id=47322">47322</a>
</td>
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<th>Summary</th>
<td>Severe optimizer regression with LLVM 11.0.0-rc2
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>11.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>release blocker
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Interprocedural Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kinke@gmx.net
</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=23896" name="attach_23896" title="unoptimized input IR">attachment 23896</a> <a href="attachment.cgi?id=23896&action=edit" title="unoptimized input IR">[details]</a></span>
unoptimized input IR
Hi, not sure whether I've chosen the right bug component, but anyway: I've hit
an apparent severe regression while testing LLVM 11-rc2 with LDC, on both Linux
and macOS x86_64. I've attached the unoptimized .ll produced by LDC.
With LLVM 10, `opt -O3 -mtriple=x86_64-linux-gnu` yields the expected:
---
define i32 @main() local_unnamed_addr #0 {
forbody.preheader.i:
ret i32 0
}
---
while LLVM 11-rc2 comes up with an *undefined* branch:
---
define i32 @main() local_unnamed_addr #0 {
forbody.i:
br i1 undef, label %assertPassed, label %forbody.i.2
assertPassed: ; preds = %forbody.i
ret i32 0
forbody.i.2: ; preds = %forbody.i
tail call void @__assert(i8* getelementptr inbounds ([55 x i8], [55 x i8]*
@.str.4, i64 0, i64 0), i8* getelementptr inbounds ([55 x i8], [55 x i8]*
@.str.5, i64 0, i64 0), i32 2432) #2
unreachable
}
---</pre>
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