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<head>
<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang crashes at -O0 on valid code with inlined assembly on x86_64-linux-gnu"
href="https://llvm.org/bugs/show_bug.cgi?id=24884">24884</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang crashes at -O0 on valid code with inlined assembly on x86_64-linux-gnu
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>su@cs.ucdavis.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The current clang trunk crashes when compiling the following code at -O0 (but
not at -O1 and above) in both 32-bit and 64-bit modes on x86_64-linux-gnu.
It is a regression from 3.1.
$ clang-trunk -v
clang version 3.8.0 (trunk 248020)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/tools/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.2
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.1.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.7.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.2
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.1.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64
$
$ clang-trunk -O1 small.c
$ clang-3.1 -O0 small.c
$
$ clang-trunk -O0 small.c
Instruction uses an allocated register
UNREACHABLE executed at /tmp/llvm/lib/CodeGen/RegAllocFast.cpp:361!
#0 0x2de285d llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/usr/local/clang-trunk/bin/clang+0x2de285d)
#1 0x2de1ee6 llvm::sys::RunSignalHandlers()
(/usr/local/clang-trunk/bin/clang+0x2de1ee6)
#2 0x2de405e (/usr/local/clang-trunk/bin/clang+0x2de405e)
#3 0x7f1808a30340 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x10340)
#4 0x7f18079cbcc9 gsignal
/build/buildd/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0
#5 0x7f18079cf0d8 abort /build/buildd/eglibc-2.19/stdlib/abort.c:91:0
#6 0x2dca32d llvm::llvm_unreachable_internal(char const*, char const*, unsigned
int) (/usr/local/clang-trunk/bin/clang+0x2dca32d)
#7 0x25b5862 (/usr/local/clang-trunk/bin/clang+0x25b5862)
#8 0x25b280f (/usr/local/clang-trunk/bin/clang+0x25b280f)
#9 0x254496c llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
(/usr/local/clang-trunk/bin/clang+0x254496c)
#10 0x2d32404 llvm::FPPassManager::runOnFunction(llvm::Function&)
(/usr/local/clang-trunk/bin/clang+0x2d32404)
#11 0x2d3264b llvm::FPPassManager::runOnModule(llvm::Module&)
(/usr/local/clang-trunk/bin/clang+0x2d3264b)
#12 0x2d32b25 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/usr/local/clang-trunk/bin/clang+0x2d32b25)
#13 0x9db71d clang::EmitBackendOutput(clang::DiagnosticsEngine&,
clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions
const&, llvm::StringRef, llvm::Module*, clang::BackendAction,
llvm::raw_pwrite_stream*) (/usr/local/clang-trunk/bin/clang+0x9db71d)
#14 0x9bdf03 (/usr/local/clang-trunk/bin/clang+0x9bdf03)
#15 0xc44da6 clang::ParseAST(clang::Sema&, bool, bool)
(/usr/local/clang-trunk/bin/clang+0xc44da6)
#16 0x7764e5 clang::FrontendAction::Execute()
(/usr/local/clang-trunk/bin/clang+0x7764e5)
#17 0x74384c clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
(/usr/local/clang-trunk/bin/clang+0x74384c)
#18 0x723477 clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
(/usr/local/clang-trunk/bin/clang+0x723477)
#19 0x719355 cc1_main(llvm::ArrayRef<char const*>, char const*, void*)
(/usr/local/clang-trunk/bin/clang+0x719355)
#20 0x721b0f main (/usr/local/clang-trunk/bin/clang+0x721b0f)
#21 0x7f18079b6ec5 __libc_start_main
/build/buildd/eglibc-2.19/csu/libc-start.c:321:0
#22 0x718de9 _start (/usr/local/clang-trunk/bin/clang+0x718de9)
Stack dump:
0. Program arguments: /usr/local/clang-trunk/bin/clang -cc1 -triple
x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -main-file-name
small.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim
-fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables
-fuse-init-array -target-cpu x86-64 -target-linker-version 2.24
-dwarf-column-info -resource-dir /usr/local/clang-trunk/bin/../lib/clang/3.8.0
-internal-isystem /usr/local/include -internal-isystem
/usr/local/clang-trunk/bin/../lib/clang/3.8.0/include -internal-externc-isystem
/usr/include/x86_64-linux-gnu -internal-externc-isystem /include
-internal-externc-isystem /usr/include -O0 -fdebug-compilation-dir
/data2/c-hunter-results/C/tokenmutate-bugs/20150918-clang-build-test92-1
-ferror-limit 19 -fmessage-length 109 -fobjc-runtime=gcc
-fdiagnostics-show-option -fcolor-diagnostics -o /tmp/small-79a9dc.o -x c
small.c
1. <eof> parser at end of file
2. Code generation
3. Running pass 'Function Pass Manager' on module 'small.c'.
4. Running pass 'Fast Register Allocator' on function '@main'
clang: error: unable to execute command: Aborted
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 3.8.0 (trunk 248020)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/tools/bin
clang: note: diagnostic msg: PLEASE submit a bug report to
<a href="http://llvm.org/bugs/">http://llvm.org/bugs/</a> and include the crash backtrace, preprocessed source, and
associated run script.
clang: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/small-102ab9.c
clang: note: diagnostic msg: /tmp/small-102ab9.sh
clang: note: diagnostic msg:
********************
$
---------------------------------------------
int
main ()
{
register int x asm ("r8");
__asm ("mov %0, %1;" : "=r" (x) , "=r" (x));
return 0;
}</pre>
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