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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 - opt crash with "-mem2reg -lcssa -loop-rotate" Assertion `L->isRecursivelyLCSSAForm(*DT, *LI) && "Requested to preserve LCSSA, but it's already broken."' failed."
href="https://bugs.llvm.org/show_bug.cgi?id=48871">48871</a>
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</tr>
<tr>
<th>Summary</th>
<td>opt crash with "-mem2reg -lcssa -loop-rotate" Assertion `L->isRecursivelyLCSSAForm(*DT, *LI) && "Requested to preserve LCSSA, but it's already broken."' failed.
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</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>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>suochenyao@163.com
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24416" name="attach_24416" title="IR that is passed to opt">attachment 24416</a> <a href="attachment.cgi?id=24416&action=edit" title="IR that is passed to opt">[details]</a></span>
IR that is passed to opt
*******************************************************************************
OS and Platform:
CentOS Linux release 7.8.2003 (Core), x86_64 GNU/Linux
*******************************************************************************
Program:
char c=0;
char a=0;
short b=0;
int d=0;
char e() {
long f;
for (; 1;)
for (;;) {
char g;
if (b)
break;
f = c;
}
for (; 0;) {
int h;
f & 0;
for (; 0; 1)
return d;
}
if (a)
for (; 0;)
for (; 0; 0)
return 0;
}
int main() {}
*******************************************************************************
clang version:
$ clang -v
clang version 10.0.0 (/home/suocy/src/llvm-dev/llvm/tools/clang
65acf43270ea2894dffa0d0b292b92402f80c8cb) (/home/suocy/src/llvm-dev/llvm
2c4ca6832fa6b306ee6a7010bfb80a3f2596f824)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/suocy/bin/llvm-dev/bin
Found candidate GCC installation:
/opt/rh/devtoolset-7/root/usr/lib/gcc/x86_64-redhat-linux/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.8.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/4.8.5
Selected GCC installation:
/opt/rh/devtoolset-7/root/usr/lib/gcc/x86_64-redhat-linux/7
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
*******************************************************************************
Command Lines:
$ clang -O3 -mllvm -disable-llvm-optzns -c -emit-llvm a.c -o a.bc
a.c:16:7: warning: expression result unused [-Wunused-value]
f & 0;
~ ^ ~
a.c:17:15: warning: expression result unused [-Wunused-value]
for (; 0; 1)
^
a.c:22:17: warning: expression result unused [-Wunused-value]
for (; 0; 0)
^
3 warnings generated.
$ opt -mem2reg -lcssa -loop-rotate a.bc -o a.opt.bc
opt: /home/suocy/src/llvm-dev/llvm/lib/Transforms/Utils/LoopSimplify.cpp:721:
bool llvm::simplifyLoop(llvm::Loop*, llvm::DominatorTree*, llvm::LoopInfo*,
llvm::ScalarEvolution*, llvm::AssumptionCache*, llvm::MemorySSAUpdater*, bool):
Assertion `L->isRecursivelyLCSSAForm(*DT, *LI) && "Requested to preserve LCSSA,
but it's already broken."' failed.
Stack dump:
0. Program arguments: /home/suocy/bin/llvm-dev/bin/opt -mem2reg -lcssa
-loop-rotate a.bc -o a.opt.bc
1. Running pass 'Function Pass Manager' on module 'a.bc'.
2. Running pass 'Canonicalize natural loops' on function '@e'
#0 0x0000000002686b9a llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/home/suocy/bin/llvm-dev/bin/opt+0x2686b9a)
#1 0x0000000002684ae4 llvm::sys::RunSignalHandlers()
(/home/suocy/bin/llvm-dev/bin/opt+0x2684ae4)
#2 0x0000000002684c12 SignalHandler(int)
(/home/suocy/bin/llvm-dev/bin/opt+0x2684c12)
#3 0x00007fe665b32630 __restore_rt (/lib64/libpthread.so.0+0xf630)
#4 0x00007fe664720387 raise (/lib64/libc.so.6+0x36387)
#5 0x00007fe664721a78 abort (/lib64/libc.so.6+0x37a78)
#6 0x00007fe6647191a6 __assert_fail_base (/lib64/libc.so.6+0x2f1a6)
#7 0x00007fe664719252 (/lib64/libc.so.6+0x2f252)
#8 0x000000000271d2dd llvm::simplifyLoop(llvm::Loop*, llvm::DominatorTree*,
llvm::LoopInfo*, llvm::ScalarEvolution*, llvm::AssumptionCache*,
llvm::MemorySSAUpdater*, bool) (/home/suocy/bin/llvm-dev/bin/opt+0x271d2dd)
#9 0x000000000271d55d (anonymous
namespace)::LoopSimplify::runOnFunction(llvm::Function&)
(/home/suocy/bin/llvm-dev/bin/opt+0x271d55d)
#10 0x0000000001fd0011 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/home/suocy/bin/llvm-dev/bin/opt+0x1fd0011)
#11 0x0000000001fd0979 llvm::FPPassManager::runOnModule(llvm::Module&)
(/home/suocy/bin/llvm-dev/bin/opt+0x1fd0979)
#12 0x0000000001fcf2ee llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/home/suocy/bin/llvm-dev/bin/opt+0x1fcf2ee)
#13 0x00000000007dca14 main (/home/suocy/bin/llvm-dev/bin/opt+0x7dca14)
#14 0x00007fe66470c555 __libc_start_main (/lib64/libc.so.6+0x22555)
#15 0x0000000000860d15 _start (/home/suocy/bin/llvm-dev/bin/opt+0x860d15)
Aborted</pre>
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