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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Broken function found with "opt -lowerswitch -loop-instsimplify -jump-threading -loop-versioning-licm""
href="https://bugs.llvm.org/show_bug.cgi?id=41542">41542</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Broken function found with "opt -lowerswitch -loop-instsimplify -jump-threading -loop-versioning-licm"
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>cszide@163.com
</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=21802" name="attach_21802" title=".bc file of the source code">attachment 21802</a> <a href="attachment.cgi?id=21802&action=edit" title=".bc file of the source code">[details]</a></span>
.bc file of the source code
$clang -v
clang version 9.0.0 (trunk 355281)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/jack-zhou/Documents/llvm/llvm_truck/llvm/build4/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.3.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$clang -O3 -c -emit-llvm -mllvm -disable-llvm-optzns small.c -o small.bc
$opt -lowerswitch -loop-instsimplify -jump-threading -loop-versioning-licm
small.bc -o small-opt.bc
PHI nodes must have at least one entry. If the block is dead, the PHI should
be removed!
%.lcssa = phi i32
in function f
LLVM ERROR: Broken function found, compilation aborted!
By using godbolt, it shows that llvm 7/trunk version have this problem, but
llvm 6 is fine.
--------------------------------------------------------
struct a {};
struct {
int b;
} c, d;
int e;
int f() {
int g;
for (; 7;)
h:;
{
struct a *i[1];
struct a j;
int k[1];
for (; e;)
for (; g; g++)
i[g] = &c;
k[e] = 6;
if (d.b)
goto h;
for (; 0;)
return 0;
}
}</pre>
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