<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <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 on valid code at -Os and -O2 on x86_64-linux-gnu"
   href="http://llvm.org/bugs/show_bug.cgi?id=18042">18042</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>clang crashes on valid code at -Os and -O2 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>llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>The current clang trunk crashes when compiling the following testcase at -Os
and -O2 on x86_64-linux-gnu in both 32-bit and 64-bit modes. 

This is a regression from clang 3.3.

$ clang-trunk -v
clang version 3.5 (trunk 195545)
Target: x86_64-unknown-linux-gnu
Thread model: posix
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.6
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/4.6.3
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6

$ clang-trunk -O1 small.c; a.out
$ clang-3.3 -Os small.c; a.out

$ gcc-trunk -Os small.c; a.out
$ icc -Os small.c; a.out

$ clang-trunk -Os small.c; a.out
clang: /tmp/llvm/lib/Transforms/Utils/LCSSA.cpp:159: virtual bool <anonymous
namespace>::LCSSA::runOnLoop(llvm::Loop *, llvm::LPPassManager &): Assertion
`L->isLCSSAForm(*DT)' failed.
0  clang           0x00000000021c1215 llvm::sys::PrintStackTrace(_IO_FILE*) +
37
1  clang           0x00000000021c1653
2  libpthread.so.0 0x00007f83d0ab4cb0
3  libc.so.6       0x00007f83cf8d6425 gsignal + 53
4  libc.so.6       0x00007f83cf8d9b8b abort + 379
5  libc.so.6       0x00007f83cf8cf0ee
6  libc.so.6       0x00007f83cf8cf192
7  clang           0x0000000001ed4716
8  clang           0x0000000001fa29a0
llvm::LPPassManager::runOnFunction(llvm::Function&) + 944
9  clang           0x000000000215656a
llvm::FPPassManager::runOnFunction(llvm::Function&) + 362
10 clang           0x0000000001f1f4aa
11 clang           0x0000000002156d97
llvm::legacy::PassManagerImpl::run(llvm::Module&) + 999
12 clang           0x000000000084eb03
clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions
const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::Module*,
clang::BackendAction, llvm::raw_ostream*) + 5955
13 clang           0x000000000084c7c6
14 clang           0x00000000009bd6e3 clang::ParseAST(clang::Sema&, bool, bool)
+ 515
15 clang           0x000000000084ba42 clang::CodeGenAction::ExecuteAction() +
514
16 clang           0x00000000006c1740 clang::FrontendAction::Execute() + 112
17 clang           0x000000000069eaad
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 925
18 clang           0x0000000000685fc0
clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 2880
19 clang           0x000000000067e23f cc1_main(char const**, char const**, char
const*, void*) + 687
20 clang           0x0000000000684220 main + 9184
21 libc.so.6       0x00007f83cf8c176d __libc_start_main + 237
22 clang           0x000000000067dec9
Stack dump:
0.    Program arguments: /usr/local/clang-trunk/bin/clang -cc1 -triple
x86_64-unknown-linux-gnu -emit-obj -disable-free -main-file-name small.c
-mrelocation-model static -fmath-errno -masm-verbose -mconstructor-aliases
-munwind-tables -target-cpu x86-64 -target-linker-version 2.22
-momit-leaf-frame-pointer -resource-dir
/usr/local/clang-trunk/bin/../lib/clang/3.5 -internal-isystem
/usr/local/include -internal-isystem
/usr/local/clang-trunk/bin/../lib/clang/3.5/include -internal-externc-isystem
/usr/include/x86_64-linux-gnu -internal-externc-isystem /include
-internal-externc-isystem /usr/include -Os -fdebug-compilation-dir
/data2/c-hunter-results/C/trans-bugs/20131123-clang-m32-m64-O2-Os-build-test258680
-ferror-limit 19 -fmessage-length 103 -mstackrealign -fobjc-runtime=gcc
-fdiagnostics-show-option -fcolor-diagnostics -vectorize-loops -vectorize-slp
-o /tmp/small-c06d46.o -x c small.c 
1.    <eof> parser at end of file
2.    Per-module optimization passes
3.    Running pass 'CallGraph Pass Manager' on module 'small.c'.
4.    Running pass 'Loop Pass Manager' on function '@bar'
5.    Running pass 'Loop-Closed SSA Form Pass' on basic block
'%for.condthread-pre-split'
clang: error: unable to execute command: Aborted (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
clang version 3.5 (trunk 195545)
Target: x86_64-unknown-linux-gnu
Thread model: posix
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-87fe25.c
clang: note: diagnostic msg: /tmp/small-87fe25.sh
clang: note: diagnostic msg: 

********************



------------------------------------------------


int a, b, c, d, e, f, g, h;

int 
foo (int p) 

  return p; 
}

void 
bar ()
{
  int *i = &h, *j = 0;
 l1:
  for (; d;)
    ;
 l2:
  e = 0;
  if (foo (1))
    a = 0;
  for (; a >= 0; a--)
    {
      for (f = 1; f; f--)
    {
      *i = 0;
      j = &d;
    }
      for (g = 0; g < 1; g++)
    {
      *i ^= 1;
      *j = 0;
      if (b)
        goto l2;
    }
      if (c)
    goto l1;
    }
}

int 
main ()
{
  bar ();
  return 0;
}</pre>
        </div>
      </p>
      <hr>
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      <ul>
          <li>You are on the CC list for the bug.</li>
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