<html>
    <head>
      <base href="https://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 at -O1 and above on x86_64-linux-gnu"
   href="https://llvm.org/bugs/show_bug.cgi?id=26044">26044</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>clang crashes at -O1 and above 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 and 3.7.x crash when compiling the following test case
on x86_64-linux-gnu at -O1 and above in both 32-bit and 64-bit modes. 

This is a regression from 3.6.x. 


$ clang-trunk -v
clang version 3.8.0 (trunk 256854)
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/4.9.3
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.2.1
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/4.8.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.2.1
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 -O0 -c small.c
$ clang-3.6 -O1 -c small.c
$
$ clang-trunk -O1 -c small.c
clang: /tmp/llvm/lib/Transforms/Scalar/SCCP.cpp:121: bool (anonymous
namespace)::LatticeVal::markConstant(llvm::Constant *): Assertion
`getLatticeValue() == forcedconstant && "Cannot move from overdefined to
constant!"' failed.
#0 0x0000000003043258 llvm::sys::PrintStackTrace(llvm::raw_ostream&)
(/usr/local/clang-trunk/bin/clang+0x3043258)
#1 0x00000000030439c7 (/usr/local/clang-trunk/bin/clang+0x30439c7)
#2 0x00007fa4bfa51340 __restore_rt
(/lib/x86_64-linux-gnu/libpthread.so.0+0x10340)
#3 0x00007fa4bea5bcc9 gsignal
/build/buildd/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0
#4 0x00007fa4bea5f0d8 abort /build/buildd/eglibc-2.19/stdlib/abort.c:91:0
#5 0x00007fa4bea54b86 __assert_fail_base
/build/buildd/eglibc-2.19/assert/assert.c:92:0
#6 0x00007fa4bea54c32 (/lib/x86_64-linux-gnu/libc.so.6+0x2fc32)
#7 0x000000000294710d (/usr/local/clang-trunk/bin/clang+0x294710d)
#8 0x0000000002949f90 (/usr/local/clang-trunk/bin/clang+0x2949f90)
#9 0x0000000002949c83 (/usr/local/clang-trunk/bin/clang+0x2949c83)
#10 0x000000000294580c (/usr/local/clang-trunk/bin/clang+0x294580c)
#11 0x000000000294e5dd (/usr/local/clang-trunk/bin/clang+0x294e5dd)
#12 0x0000000002f89f35 llvm::legacy::PassManagerImpl::run(llvm::Module&)
(/usr/local/clang-trunk/bin/clang+0x2f89f35)
#13 0x0000000000a0ab13 clang::EmitBackendOutput(clang::DiagnosticsEngine&,
clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions
const&, llvm::StringRef, llvm::Module*, clang::BackendAction,
llvm::raw_pwrite_stream*, std::unique_ptr<llvm::FunctionInfoIndex,
std::default_delete<llvm::FunctionInfoIndex> >)
(/usr/local/clang-trunk/bin/clang+0xa0ab13)
#14 0x00000000009eb5db (/usr/local/clang-trunk/bin/clang+0x9eb5db)
#15 0x0000000000c9f1f6 clang::ParseAST(clang::Sema&, bool, bool)
(/usr/local/clang-trunk/bin/clang+0xc9f1f6)
#16 0x000000000077edb5 clang::FrontendAction::Execute()
(/usr/local/clang-trunk/bin/clang+0x77edb5)
#17 0x0000000000748d31
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
(/usr/local/clang-trunk/bin/clang+0x748d31)
#18 0x0000000000727a1c
clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
(/usr/local/clang-trunk/bin/clang+0x727a1c)
#19 0x000000000071d8e8 cc1_main(llvm::ArrayRef<char const*>, char const*,
void*) (/usr/local/clang-trunk/bin/clang+0x71d8e8)
#20 0x00000000007260d3 main (/usr/local/clang-trunk/bin/clang+0x7260d3)
#21 0x00007fa4bea46ec5 __libc_start_main
/build/buildd/eglibc-2.19/csu/libc-start.c:321:0
#22 0x000000000071d374 _start (/usr/local/clang-trunk/bin/clang+0x71d374)
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 -mthread-model posix -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64
-target-linker-version 2.24 -momit-leaf-frame-pointer -dwarf-column-info
-debugger-tuning=gdb -coverage-file /data2/small.c -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 -O1 -fdebug-compilation-dir /data2
-ferror-limit 19 -fmessage-length 160 -fobjc-runtime=gcc
-fdiagnostics-show-option -fcolor-diagnostics -o small.o -x c small.c
1.      <eof> parser at end of file
2.      Per-module optimization passes
3.      Running pass 'Interprocedural Sparse Conditional Constant Propagation'
on module 'small.c'.
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 3.8.0 (trunk 256854)
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-93ec74.c
clang: note: diagnostic msg: /tmp/small-93ec74.sh
clang: note: diagnostic msg:

********************
$


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


int a, b, c;

static int
fn1 (int p1)

  return p1 ? p1 : -p1;
}

void
fn2 ()

  char d;
  b = 0;
  for (; b < 1;)
    goto lbl;
  int *e = &c;
  for (;;)
    { 
      if (d)
      lbl:
        a = 0;
      fn1 (*e);
      e = 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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